Science.gov

Sample records for aircraft based measurements

  1. Aircraft-based measurements of the carbon footprint of Indianapolis.

    PubMed

    Mays, Kelly L; Shepson, Paul B; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Gurney, Kevin R

    2009-10-15

    The quantification of greenhouse gas emissions requires high precision measurements made with high spatial resolution. Here we describe measurements of carbon dioxide (CO2) and methane (CH4) conducted using Purdue University's Airborne Laboratory for Atmospheric Research (ALAR), aimed at the quantification of the "footprints" for these greenhouse gases for Indianapolis, IN. A cavity ring-down spectrometer measured atmospheric concentrations, and flask samples were obtained at various points for comparison. Coupled with pressure, temperature, and model-derived horizontal winds, these measurements allow for flux estimation. Long horizontal transects were flown perpendicular to the wind downwind of the city. Emissions were calculated using the wind speed and the difference between the concentration in the plume and the background concentration. A kriging method is applied to interpolate the measured values to a vertical plane traced out by the flight pattern within the mixed layer. Results show the urban plume is clearly distinguishable in the downwind concentrations for most flights. Additionally, there is large variability in the measured day-to-day emissions fluxes as well as in the relative CH4 and CO2 fluxes. Uncertainties in the method are discussed, and its potential utilityin determining sector-based emission factors is shown.

  2. Validation of Aura OMI by Aircraft and Ground-Based Measurements

    NASA Astrophysics Data System (ADS)

    McPeters, R. D.; Petropavlovskikh, I.; Kroon, M.

    2006-12-01

    Both aircraft-based and ground-based measurements have been used to validate ozone measurements by the OMI instrument on Aura. Three Aura Validation Experiment (AVE) flights have been conducted, in November 2004 and June 2005 with the NASA WB57, and in January/February 2005 with the NASA DC-8. On these flights, validation of OMI was primarily done using data from the CAFS (CCD Actinic Flux Spectroradiometer) instrument, which is used to measure total column ozone above the aircraft. These measurements are used to differentiate changes in stratospheric ozone from changes in total column ozone. Also, changes in ozone over high clouds measured by OMI were checked in a flight over tropical storm Arlene on a flight on June 11th. Ground-based measurements were made during the SAUNA campaign in Sodankyla, Finland, in March and April 2006. Both total column ozone and the ozone vertical distribution were validated.

  3. Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin.

    PubMed

    Lavoie, Tegan N; Shepson, Paul B; Cambaliza, Maria O L; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Yacovitch, Tara I; Herndon, Scott C; Lan, Xin; Lyon, David

    2015-07-01

    We report measurements of methane (CH4) emission rates observed at eight different high-emitting point sources in the Barnett Shale, Texas, using aircraft-based methods performed as part of the Barnett Coordinated Campaign. We quantified CH4 emission rates from four gas processing plants, one compressor station, and three landfills during five flights conducted in October 2013. Results are compared to other aircraft- and surface-based measurements of the same facilities, and to estimates based on a national study of gathering and processing facilities emissions and 2013 annual average emissions reported to the U.S. EPA Greenhouse Gas Reporting Program (GHGRP). For the eight sources, CH4 emission measurements from the aircraft-based mass balance approach were a factor of 3.2-5.8 greater than the GHGRP-based estimates. Summed emissions totaled 7022 ± 2000 kg hr(-1), roughly 9% of the entire basin-wide CH4 emissions estimated from regional mass balance flights during the campaign. Emission measurements from five natural gas management facilities were 1.2-4.6 times larger than emissions based on the national study. Results from this study were used to represent "super-emitters" in a newly formulated Barnett Shale Inventory, demonstrating the importance of targeted sampling of "super-emitters" that may be missed by random sampling of a subset of the total.

  4. Assimilating aircraft-based measurements to improve forecast accuracy of volcanic ash transport

    NASA Astrophysics Data System (ADS)

    Fu, G.; Lin, H. X.; Heemink, A. W.; Segers, A. J.; Lu, S.; Palsson, T.

    2015-08-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash transport forecast in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be run with Eruption Source Parameters (ESP) such as plume height and mass eruption rate as input, and with data assimilation techniques to continuously improve the initial conditions of the forecast. Reliable and accurate ash measurements are crucial for providing a successful ash clouds advice. In this paper, simulated aircraft-based measurements, as one type of volcanic ash measurements, will be assimilated into a transport model to identify the potential benefit of this kind of observations in an assimilation system. The results show assimilating aircraft-based measurements can significantly improve the state of ash clouds, and further providing an improved forecast as aviation advice. We also show that for advice of aeroplane flying level, aircraft-based measurements should be preferably taken from this level to obtain the best performance on it. Furthermore it is shown that in order to make an acceptable advice for aviation decision makers, accurate knowledge about uncertainties of ESPs and measurements is of great importance.

  5. Characterization of a Photoacoustic Aerosol Absorption Spectrometer for Aircraft-based Measurements

    NASA Astrophysics Data System (ADS)

    Mason, B. J.; Wagner, N. L.; Richardson, M.; Brock, C. A.; Murphy, D. M.; Adler, G.

    2015-12-01

    Atmospheric aerosol directly impacts the Earth's climate through extinction of incoming and outgoing radiation. The optical extinction is due to both scattering and absorption. In situ measurements of aerosol extinction and scattering are well established and have uncertainties less than 5%. However measurements of aerosol absorption typically have uncertainties of 20-30%. Development and characterization of more accurate and precise instrumentation for measurement of aerosol absorption will enable a deeper understand of significance and spatial distribution of black and brown carbon aerosol, the effect of atmospheric processes on aerosol optical properties, and influence of aerosol optical properties on direct radiative forcing. Here, we present a detailed characterization of a photoacoustic aerosol absorption spectrometer designed for deployment aboard research aircraft. The spectrometer operates at three colors across the visible spectrum and is calibrated in the field using ozone. The field calibration is validated in the laboratory using synthetic aerosol and simultaneous measurements of extinction and scattering. In addition, the sensitivity of the instrument is characterized under conditions typically encountered during aircraft sampling e.g. as a function of changing pressure. We will apply this instrument characterization to ambient aerosol absorption data collected during the SENEX and SEAC4RS aircraft based field campaigns.

  6. Application of an acoustic noise removal method to aircraft-based atmospheric temperature measurements

    NASA Astrophysics Data System (ADS)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Eaton, Frank D.; McCrae, Kim A.

    2003-01-01

    An acoustic noise removal method is used to reject engine acoustical disturbances from aircraft-based atmospheric temperature measurements. Removal of engine noise from atmospheric temperature measurements allows a larger wave number range to be fit while quantifying the magnitude of atmospheric temperature turbulence. The larger wave number range was found to result in a more statistically certain spectral slope estimate, with up to a 50% reduction in the standard deviation of measured spectral slopes. The noise removal technique was found to break down under conditions of weak atmospheric temperature turbulence where the engine acoustical disturbance can be several orders of magnitude larger than atmospheric temperature turbulence.

  7. Comparison of ozone measurement techniques using aircraft, balloon, and ground-based measurements

    NASA Technical Reports Server (NTRS)

    Briehl, D.; Reck, G. M.

    1977-01-01

    In order to verify the ultraviolet absorption technique used in the Global Atmospheric Sampling Program, two flight experiments were conducted employing several techniques, both in situ and remote, for measuring atmospheric ozone. The first experiment used the NASA CV-990 equipped with an ultraviolet absorption ozone monitor and an ultraviolet spectrophotometer, a balloon ozonesonde, and a Dobson station for determining and comparing the ozone concentration data. A second experiment compared ozone data from an automated sampling system aboard a B-747 with data from a manned system installed on the NASA CV-990 during a cross-country flight with both aircraft following the same flight path separated by 32 kilometers.

  8. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang

    2016-07-01

    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  9. Loss rate of NO y from a power plant plume based on aircraft measurements

    NASA Astrophysics Data System (ADS)

    Gillani, N. V.; Luria, M.; Valente, R. J.; Tanner, R. L.; Imhoff, R. E.; Meagher, J. F.

    1998-09-01

    This study was motivated by the recent work of Buhr et al. [1996] which reported losses of NOy from large power plant plumes as high as 0.25 hour-1, much higher than generally accepted values. If true, conclusions pertaining to the efficiency of ozone and nitrate production in the lower troposphere would need major revisions. The results of Buhr et al. were based on aircraft measurements in four TVA (Tennessee Valley Authority) power plant plumes on July 7, 1995, as part of the Nashville/Middle Tennessee Ozone Study, a measurement program of the Southern Oxidants Study (SOS), whereas the results reported in this paper are also based on measurements made in the same SOS study aboard another instrumented aircraft (the TVA helicopter), in plumes of one of these power plants (the Cumberland Steam Plant in northwestern Tennessee) during five different days in 1994 and 1995. Between the 1994 and 1995 sampling periods, emissions of SO2 at the Cumberland plant were reduced by nearly 95% by installation of scrubbers. Our data from the one 1994 day show that the ratio of excess SO2 to NOy, in the plume core increased significantly with plume age, indicating a potentially high differential loss rate of NOy (excess loss of NOy relative to SO2) of about 0.12 hour-1. However, results based on the larger 1995 data set indicate a low differential NOy loss rate of only 0.00±0.03 hour-1, consistent with accepted low loss rates. Because the SOS-Nashville/Middle Tennessee Ozone Study was not specifically designed to explore the NOy loss issue, the question of NOy loss rates in plumes is not currently resolved and additional focused field studies are needed.

  10. Vertical distribution of aerosol optical properties based on aircraft measurements over the Loess Plateau in China.

    PubMed

    Li, Junxia; Liu, Xingang; Yuan, Liang; Yin, Yan; Li, Zhanqing; Li, Peiren; Ren, Gang; Jin, Lijun; Li, Runjun; Dong, Zipeng; Li, Yiyu; Yang, Junmei

    2015-08-01

    Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (σsc), absorption coefficients (σab), Angström exponent (α), single scattering albedo (ω), backscattering ratio (βsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc(')) were obtained. The mean statistical values of σsc were 77.45 Mm(-1) (at 450 nm), 50.72 Mm(-1) (at 550n m), and 32.02 Mm(-1) (at 700 nm). The mean value of σab was 7.62 Mm(-1) (at 550 nm). The mean values of α, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Qsc and Qsc(') showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Qsc, Qsc('), σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.

  11. A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Rinehart, Aidan Walker

    2015-01-01

    This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

  12. A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Rinehart, Aidan W.

    2014-01-01

    This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

  13. Far-infrared sensor for cirrus (FIRSC): an aircraft-based Fourier-transform spectrometer to measure cloud radiance.

    PubMed

    Vanek, M D; Nolt, I G; Tappan, N D; Ade, P A; Gannaway, F C; Hamilton, P A; Lee, C; Davis, J E; Predko, S

    2001-05-01

    We describe an aircraft-based Fourier-transform spectrometer (FTS) designed to measure the Earth outgoing radiance spectrum in the far-infrared-submillimeter spectral range. The instrument features include a rapid-scan FTS to obtain high spatial resolution from a moving aircraft platform, a sensitive two-channel detector, and a CCD camera for recording the nadir cloud scene with each scan record. Such measurements demonstrate the sensitivity of Earth radiance to high clouds and provide spectral data for improving techniques for remote sensing and retrieval of atmospheric and cloud properties.

  14. Aircraft measurements of wave cloud

    NASA Astrophysics Data System (ADS)

    Cui, Z.; Blyth, A. M.; Bower, K. N.; Crosier, J.; Choularton, T.

    2012-05-01

    In this paper, aircraft measurements are presented of liquid phase (ice-free) wave clouds made at temperatures greater than -5 °C that formed over Scotland, UK. The horizontal variations of the vertical velocity across wave clouds display a distinct pattern. The maximum updraughts occur at the upshear flanks of the clouds and the strong downdraughts at the downshear flanks. The cloud droplet concentrations were a couple of hundreds per cubic centimetres, and the drops generally had a mean diameter between 15-45 μm. A small proportion of the drops were drizzle. A new definition of a mountain-wave cloud is given, based on the measurements presented here and previous studies. The results in this paper provide a case for future numerical simulation of wave cloud and the interaction between wave and clouds.

  15. Aircraft Lightning Electromagnetic Environment Measurement

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

    2011-01-01

    This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

  16. Relationship between satellite-derived vegetation indices and aircraft-based CO2 measurements

    SciTech Connect

    Cihlar, J.; Caramori, P.H.; Schuepp, P.H.; Desjardins, R.L.; Macpherson, J.I. McGill Univ., Montreal Agriculture Canada, Centre for Land and Biological Resources Research, Ottawa National Research Council of Canada, Inst. for Aerospace Research, Ottawa )

    1992-11-01

    The objective of this study was to analyze the relationship between satellite-derived vegetation indices and CO2 uptake, as an initial step in exploring the possibility of using a satellite-derived vegetation index as a measure of net photosynthesis. The study area included the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) site located on the Konza prairie and adjacent area as well as a transect between Manhattan and Salina. One third of the transect exhibited vegetation and terrain characteristics similar to those on the FIFE site, whereas cultivated land predominated in the remaining portion of the 75-km-long flight line. In June, July, August, and October 1987, several CO2 data sets were obtained using the National Research Council of Canada's Twin Otter research aircraft. The normalized difference vegetation index (NDVI) and the simple ratio (SR) were computed from NOAA AVHRR data acquired as part of FIFE. Aircraft and satellite data were processed to obtain spatially coincident and locally representative flux values. Results show a linear relationship between NDVI and CO2 uptake during a single day; however, a nonlinear relationship emerged when all data sets were combined. The data from FIFE and the regional transect were consistent for one date but differed for other periods. Overall, about 60 percent of total variability in CO2 flux was accounted for by the NDVI and 74 percent by the SR. 14 refs.

  17. Recommendations for field measurements of aircraft noise

    NASA Technical Reports Server (NTRS)

    Marsh, A. H.

    1982-01-01

    Specific recommendations for environmental test criteria, data acquisition procedures, and instrument performance requirements for measurement of noise levels produced by aircraft in flight are provided. Recommendations are also given for measurement of associated airplane and engine parameters and atmospheric conditions. Recommendations are based on capabilities which were available commercially in 1981; they are applicable to field tests of aircraft flying subsonically past microphones located near the surface of the ground either directly under or to the side of a flight path. Aircraft types covered by the recommendations include fixed-wing airplanes powered by turbojet or turbofan engines or by propellers. The recommended field-measurement procedures are consistent with assumed requirements for data processing and analysis.

  18. Recommendations for field measurements of aircraft noise

    NASA Astrophysics Data System (ADS)

    Marsh, A. H.

    1982-04-01

    Specific recommendations for environmental test criteria, data acquisition procedures, and instrument performance requirements for measurement of noise levels produced by aircraft in flight are provided. Recommendations are also given for measurement of associated airplane and engine parameters and atmospheric conditions. Recommendations are based on capabilities which were available commercially in 1981; they are applicable to field tests of aircraft flying subsonically past microphones located near the surface of the ground either directly under or to the side of a flight path. Aircraft types covered by the recommendations include fixed-wing airplanes powered by turbojet or turbofan engines or by propellers. The recommended field-measurement procedures are consistent with assumed requirements for data processing and analysis.

  19. Comparing modeled isoprene with aircraft-based measurements in the atmospheric boundary layer.

    SciTech Connect

    Doskey, P.; Gao, W.

    1997-12-12

    Nonmethane hydrocarbons (NMHCs) are involved in a complex series of reactions that regulate the levels of oxidants in the troposphere. Isoprene (C{sub 5}H{sub 8}), the primary NMHC emitted from deciduous trees, is one of the most important reactive hydrocarbons in the troposphere. The amount of isoprene entering the free troposphere is regulated by the compound's rate of emission from leaves and by chemical and physical processes in the forest canopy and the atmospheric boundary layer (ABL). This study uses a coupled canopy-ABL model to simulate these complex processes and compares calculated isoprene concentration profiles with those measured during aircraft flights above a forested region in the northeastern US. Land use information is coupled with satellite remote sensing data to describe spatial changes in canopy density during the field measurements. The high-resolution transport-chemistry model of Gao et al. (1993) for the ABL and the forest canopy layer is used to simulate vertical changes in isoprene concentration due to turbulent mixing and chemical reactions. The one-dimensional (1-D) ABL model includes detailed radiation transfer, turbulent diffusion, biogenic emissions, dry deposition, and chemical processes within the forest canopy and the ABL. The measured profiles are compared with the model simulations to investigate the biological, physical, and chemical processes that regulate the levels of isoprene within the ABL.

  20. Aircraft measurements of wave clouds

    NASA Astrophysics Data System (ADS)

    Cui, Z.; Blyth, A. M.; Bower, K. N.; Crosier, J.; Choularton, T.

    2012-10-01

    In this paper, aircraft measurements are presented of liquid phase (ice-free) wave clouds made at temperatures greater than -5°C that formed over Scotland, UK. The horizontal variations of the vertical velocity across wave clouds display a distinct pattern. The maximum updraughts occur at the upshear flanks of the clouds and the strong downdraughts at the downshear flanks. The cloud droplet concentrations were a couple of hundreds per cubic centimetres, and the drops generally had a mean diameter between 15-45 μm. A small proportion of the drops were drizzle. The measurements presented here and in previous recent studies suggest a different interaction of dynamics and microphysics in wave clouds from the accepted model. The results in this paper provide a case for future numerical simulation of wave cloud and the interaction between wave and cloud.

  1. Measurement of In-Flight Aircraft Emissions

    NASA Technical Reports Server (NTRS)

    Sokoloski, M.; Arnold, C.; Rider, D.; Beer, R.; Worden, H.; Glavich, T.

    1995-01-01

    Aircraft engine emission and their chemical and physical evolution can be measured in flight using high resolution infrared spectroscopy. The Airborne Emission Spectrometer (AES), designed for remote measure- ments of atmosphere emissions from an airborne platform, is an ideal tool for the evaluation of aircraft emissions and their evolution. Capabilities of AES will be discussed. Ground data will be given.

  2. Radiation exposure measurement onboard civil aircraft.

    PubMed

    Beaujean, R; Burmeister, S; Petersen, F; Reitz, G

    2005-01-01

    The active dosemeter DOSTEL based on two silicon planar detectors was flown on civil aircraft flights to study the radiation exposure of air crew members. The altitude and latitude dependence of count and dose rates as well as long-term variations are measured. After calibration of the DOSTEL response against measurements of a TEPC instrument, total dose-equivalent values for various flights are compared with H*(10) calculations by EPCARD yielding a ratio of 1.02 +/- 0.09 (standard variation).

  3. Improving and Assessing Aircraft-based Greenhouse Gas Emission Rate Measurements at Indianapolis as part of the INFLUX project.

    NASA Astrophysics Data System (ADS)

    Heimburger, A. M. F.; Shepson, P. B.; Stirm, B. H.; Susdorf, C.; Cambaliza, M. O. L.

    2015-12-01

    Since the Copenhagen accord in 2009, several countries have affirmed their commitment to reduce their greenhouse gas emissions. The United States and Canada committed to reduce their emissions by 17% below 2005 levels, by 2020, Europe by 14% and China by ~40%. To achieve such targets, coherent and effective strategies in mitigating atmospheric carbon emissions must be implemented in the next decades. Whether such goals are actually achieved, they require that reductions are "measurable", "reportable", and "verifiable". Management of greenhouse gas emissions must focus on urban environments since ~74% of CO2 emissions worldwide will be from cities, while measurement approaches are highly uncertain (~50% to >100%). The Indianapolis Flux Experiment (INFLUX) was established to develop, assess and improve top-down and bottom-up quantifications of urban greenhouse gas emissions. Based on an aircraft mass balance approach, we performed a series of experiments focused on the improvement of CO2, CH4 and CO emission rates quantification from Indianapolis, our final objective being to drastically improve the method overall uncertainty from the previous estimate of 50%. In November-December 2014, we conducted nine methodologically identical mass balance experiments in a short period of time (24 days, one downwind distance) for assumed constant total emission rate conditions, as a means to obtain an improved standard deviation of the mean determination. By averaging the individual emission rate determinations, we were able to obtain a method precision of 17% and 16% for CO2 and CO, respectively, at the 95%C.L. CH4 emission rates are highly variable day to day, leading to precision of 60%. Our results show that repetitive sampling can enable improvement in precision of the aircraft top-down methods through averaging.

  4. Ground and aircraft-based methane measurements in Siberia: source attribution using tracers and models

    NASA Astrophysics Data System (ADS)

    Arzoumanian, E.; Paris, J. D.; Pruvost, A.; Peng, S.; Turquety, S.; Berchet, A.; Pison, I.; Helle, J.; Arshinov, M.; Belan, B. D.

    2015-12-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas. It is also naturally emitted by a number of processes, including microbial activity in wetlands, permafrost degradation and wildfires. Our current understanding of the extent and amplitude of its natural sources, as well as the large scale driving factors, remain highly uncertain (Kirschke et al., Nature Geosci., 2013). Furthermore, high latitude regions are large natural sources of CH4 in the atmosphere. Observing boreal/Arctic CH4 variability and understanding its main driving processes using atmospheric measurements and transport model is the task of this work. YAK-AEROSIB atmospheric airborne campaigns (flights in the tropospheric layer up to 9 km connecting the two cities of Novosibirsk and Yakutsk) and continuous measurements at Fonovaya Observatory (60 km west of Tomsk - 56° 25'07"N, 84° 04'27"E) have been performed in order to provide observational data on the composition of Siberian air. The study is focused on 2012, during which a strong heat wave impacted Siberia, leading to the highest mean daily temperature values on record since the beginning of the 20th century. This abnormal drought has led to numerous large forest fires. A chemistry-transport model (CHIMERE), combined with datasets for anthropogenic (EDGAR) emissions and models for wetlands (ORCHIDEE) and wildfires (APIFLAME), is used to determine contributions of CH4 sources in the region. Recent results concerning CH4 fluxes and its atmospheric variability in the Siberian territory derived from a modeled-based analysis will be shown and discussed. This work was funded by CNRS (France), the French Ministry of Foreign Affairs, CEA (France), Presidium of RAS (Program No. 4), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5), Interdisciplinary integration projects of Siberian Branch of RAS (No. 35, No. 70, No. 131), Russian Foundation for Basic Research (grants No 14-05-00526, 14-05-00590). Kirschke, S

  5. Small Aircraft RF Interference Path Loss Measurements

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Szatkowski, George N.; Mielnik, John J.; Salud, Maria Theresa P.

    2007-01-01

    Interference to aircraft radio receivers is an increasing concern as more portable electronic devices are allowed onboard. Interference signals are attenuated as they propagate from inside the cabin to aircraft radio antennas mounted on the outside of the aircraft. The attenuation level is referred to as the interference path loss (IPL) value. Significant published IPL data exists for transport and regional category airplanes. This report fills a void by providing data for small business/corporate and general aviation aircraft. In this effort, IPL measurements are performed on ten small aircraft of different designs and manufacturers. Multiple radio systems are addressed. Along with the typical worst-case coupling values, statistical distributions are also reported that could lead to more meaningful interference risk assessment.

  6. Instrument for Aircraft-Icing and Cloud-Physics Measurements

    NASA Technical Reports Server (NTRS)

    Lilie, Lyle; Bouley, Dan; Sivo, Chris

    2006-01-01

    The figure shows a compact, rugged, simple sensor head that is part of an instrumentation system for making measurements to characterize the severity of aircraft-icing conditions and/or to perform research on cloud physics. The quantities that are calculated from measurement data acquired by this system and that are used to quantify the severity of icing conditions include sizes of cloud water drops, cloud liquid water content (LWC), cloud ice water content (IWC), and cloud total water content (TWC). The sensor head is mounted on the outside of an aircraft, positioned and oriented to intercept the ambient airflow. The sensor head consists of an open housing that is heated in a controlled manner to keep it free of ice and that contains four hot-wire elements. The hot-wire sensing elements have different shapes and sizes and, therefore, exhibit different measurement efficiencies with respect to droplet size and water phase (liquid, frozen, or mixed). Three of the hot-wire sensing elements are oriented across the airflow so as to intercept incoming cloud water. For each of these elements, the LWC or TWC affects the power required to maintain a constant temperature in the presence of cloud water.

  7. Measurement of aircraft speed and altitude

    NASA Technical Reports Server (NTRS)

    Gracey, W.

    1980-01-01

    Problems involved in measuring speed and altitude with pressure-actuated instruments (altimeter, airspeed indicator, true-airspeed indicator, Machmeter, and vertical-speed indicator) are examined. Equations relating total pressure and static pressure to the five flight quantities are presented, and criteria for the design of total and static pressure tubes are given. Calibrations of typical static pressure installations (fuselage nose, wing tip, vertical fin, and fuselage vent) are presented, various methods for flight calibration of these installations are described, and the calibration of a particular installation by two of the methods is described in detail. Equations are given for estimating the effects of pressure lag and leaks. Test procedures for the laboratory calibration of the five instruments are described, and accuracies of mechanical and electrical instruments are presented. Operational use of the altimeter for terrain clearance and vertical separation of aircraft is discussed, along with flight technical errors and overall altitude errors of aircraft in cruise operations. Altitude-measuring techniques based on a variety of properties of the Earth and the atmosphere are included. Two appendixes present airspeed and altitude tables and sample calculations for determining the various flight parameters from measured total and static pressures.

  8. Recommended procedures for measuring aircraft noise and associated parameters

    NASA Technical Reports Server (NTRS)

    Marsh, A. H.

    1977-01-01

    Procedures are recommended for obtaining experimental values of aircraft flyover noise levels (and associated parameters). Specific recommendations are made for test criteria, instrumentation performance requirements, data-acquisition procedures, and test operations. The recommendations are based on state-of-the-art measurement capabilities available in 1976 and are consistent with the measurement objectives of the NASA Aircraft Noise Prediction Program. The recommendations are applicable to measurements of the noise produced by an airplane flying subsonically over (or past) microphones located near the surface of the ground. Aircraft types covered by the recommendations are fixed-wing airplanes powered by turbojet or turbofan engines and using conventional aerodynamic means for takeoff and landing. Various assumptions with respect to subsequent data processing and analysis were made (and are described) and the recommended measurement procedures are compatible with the assumptions. Some areas where additional research is needed relative to aircraft flyover noise measurement techniques are also discussed.

  9. Global Electric Circuit Implications of Combined Aircraft Storm Electric Current Measurements and Satellite-Based Diurnal Lightning Statistics

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2011-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of thunderstorms and electrified shower clouds (ESCs) spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, and with positive and negative fields above the storms. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean thunderstorms is 1.7 A while the mean current for land thunderstorms is 1.0 A. The mean current for ocean ESCs 0.41 A and the mean current for land ESCs is 0.13 A. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal flash rate statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie curve) to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Given our data and assumptions, mean contributions to the global electric circuit are 1.1 kA (land) and 0.7 kA (ocean) from thunderstorms, and 0.22 kA (ocean) and 0.04 (land) from ESCs, resulting in a mean total conduction current estimate for the global electric circuit of 2.0 kA. Mean storm counts are 1100 for land

  10. Simulation of the Impact of New Aircraft and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses

    NASA Technical Reports Server (NTRS)

    Miller, TImothy L.; Atlas, R. M.; Black, P. G.; Case, J. L.; Chen, S. S.; Hood, R. E.; Johnson, J. W.; Jones, L.; Ruf, C. S.; Uhlborn, E. W.

    2008-01-01

    Accurate observations of surface ocean vector winds (OVW) with high spatial and temporal resolution are required for understanding and predicting tropical cyclones. As NASA's QuikSCAT and Navy's WindSat operate beyond their design life, many members of the weather and climate science communities recognize the importance of developing new observational technologies and strategies to meet the essential need for OVW information to improve hurricane intensity and location forecasts. The Hurricane Imaging Radiometer (HIRAD) is an innovative technology development which offers new and unique remotely sensed satellite observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR), which is the only proven remote sensing technique for observing tropical cyclone (TC) ocean surface wind speeds and rain rates. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology. This sensor will operate over 4-7 GHz (C-band frequencies) where the required TC remote sensing physics has been validated by both SFMR and WindSat radiometers. The instrument is described in more detail in a paper by Jones et al. presented to the Tropical Meteorology Special Symposium at this AMS Annual Meeting. Simulated HIRAD passes through a simulation of hurricane Frances are being developed to demonstrate HIRAD estimation of surface wind speed over a wide swath in the presence of heavy rain. These are currently being used in "quick" OSSEs (Observing System Simulation Experiments) with H'Wind analyses as the discriminating tool. The H'Wind analysis, a product of the Hurricane Research Division of NOAA's Atlantic , Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind

  11. Measurement of hydrogen peroxide from aircraft

    SciTech Connect

    Kok, G.L.

    1980-01-01

    Hydrogen peroxide (H/sub 2/O/sub 2/) is an important species in both the homogeneous and the heterogeneous chemistry of the troposphere. Measurement of H/sub 2/O/sub 2/ from aircraft provides information on the distribution of H/sub 2/O/sub 2/ in the troposphere and provides a great deal of additional information which cannot be obtained from ground-based measurements. Three analytical techniques for atmospheric H/sub 2/O/sub 2/ are available. Two of these are colorimetric methods involving the formation of a colored complex with titanium salt. In 1978, a chemiluminescent method for the determination of atmospheric H/sub 2/O/sub 2/ was introduced. This method involves the reaction of H/sub 2/O/sub 2/ with luminol in the presence of a copper catalyst, with the chemiluminescence serving as the basis of the analytical reaction.

  12. Power Measurement Errors on a Utility Aircraft

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    2002-01-01

    Extensive flight test data obtained from two recent performance tests of a UH 60A aircraft are reviewed. A power difference is calculated from the power balance equation and is used to examine power measurement errors. It is shown that the baseline measurement errors are highly non-Gaussian in their frequency distribution and are therefore influenced by additional, unquantified variables. Linear regression is used to examine the influence of other variables and it is shown that a substantial portion of the variance depends upon measurements of atmospheric parameters. Correcting for temperature dependence, although reducing the variance in the measurement errors, still leaves unquantified effects. Examination of the power difference over individual test runs indicates significant errors from drift, although it is unclear how these may be corrected. In an idealized case, where the drift is correctable, it is shown that the power measurement errors are significantly reduced and the error distribution is Gaussian. A new flight test program is recommended that will quantify the thermal environment for all torque measurements on the UH 60. Subsequently, the torque measurement systems will be recalibrated based on the measured thermal environment and a new power measurement assessment performed.

  13. Measurement and analysis of aircraft far-field aerodynamic noise

    NASA Technical Reports Server (NTRS)

    Healy, G. J.

    1974-01-01

    A systematic investigation of aircraft far-field radiated, aerodynamically generated noise was conducted. The test phase of the original program involved the measurement of the noise produced by five gliding aircraft in an aerodynamically clean configuration during low altitude flyovers. These aircraft had gross weights that ranged from 5785 to 173 925N (1300 to 39,000 pounds), fly-by velocities from 30 to 98.5m/sec (58 to 191.5 knots or 98 to 323 ft/sec) and wing aspect ratios from 6.59 to 18.25. The results of these measurements were used to develop an equation relating aerodynamic noise to readily evaluated physical and operational parameters of the aircraft. A non-dimensional frequency spectrum, based on the mean wing thickness, was also developed.

  14. Aircraft measurements of bromine monoxide, iodine monoxide, and glyoxal profiles in the tropics: comparison with ship-based and in situ measurements

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Koenig, T. K.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-01-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO), and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4) were measured by the CU Airborne Multi AXis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument, in situ aerosol size distributions by an Ultra High Sensitivity Aerosol Spectrometer (UHSAS), and in situ H2O by Vertical-Cavity Surface-Emitting Laser hygrometer (VCSEL). Data are presented from two research flights (RF12, RF17) aboard the NSF/NCAR GV aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project. We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols, and find O4-inferred aerosol extinction profiles at 477 nm agree within 5% with Mie calculations of extinction profiles constrained by UHSAS. CU AMAX-DOAS provides a flexible choice of geometry which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise), and to test the robustness of BrO, IO, and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01), and provides independent validation data from ship-based in situ Cavity Enhanced- and MAX-DOAS. Inside the marine boundary layer (MBL) no BrO was detected (smaller than 0.5 pptv), and 0.2-0.55 pptv IO and 32-36 pptv glyoxal were observed. The near surface concentrations agree within 20% (IO) and 10% (glyoxal) between ship and aircraft. The BrO concentration strongly

  15. Aircraft measurements and analysis of severe storms: 1976 field experiment

    NASA Technical Reports Server (NTRS)

    Sinclair, P. C.

    1982-01-01

    Severe storm aircraft measurements are documented, as well as the instrumentation and operational features of aircraft mobility capabilities. The measurements and data analyses indicate that the concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, moisture, spherics, etc., near and within severe storm systems, forecast 48 hours in advance in a 1000 nm operating radius, is feasible, and was successfully demonstrated. The measurements and analyses reveal several severe storm features and insights with respect to storm air flow circulations and inflow-outflow orientation. Precipitation downdraft air is recirculated back into the updraft core below the scud cloud in both back and front feeder type storms. In a back feeder type storm, the downdraft outflow air ahead of the storm is also recirculated back into the updraft region near cloud base.

  16. Remote measurement of pollution from aircraft

    NASA Technical Reports Server (NTRS)

    Reichle, H. G., Jr.

    1976-01-01

    This paper discusses the problem of the remote measurement of tropospheric air pollution from aircraft platforms. Following a discussion of the energy sources available for passive remote sensing and the location of the absorption bands of the gases, it describes the spectral resolution that would be required and the relative merits of the shorter and longer infrared wavelengths. It then traces the evolution of one instrument concept (the gas filter correlation radiometer) to its present state, and describes flight results that show the technique to be capable of measuring carbon monoxide over water. A new instrument is described that will allow the measurements to be extended to areas over land.

  17. Simulation of the Impact of New Aircraft- and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses and Numerical Forecasts

    NASA Technical Reports Server (NTRS)

    Miller, Timothy; Atlas, Robert; Black, Peter; Chen, Shuyi; Hood, Robbie; Johnson, James; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric; Krishnamurti, T. N.; Albers, Cerese

    2009-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the realtime airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airborne Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath ( 3 x the aircraft altitude). The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a detailed numerical model, and those results are used to construct H*Wind analyses. The H*Wind analysis, a product of the Hurricane Research Division of NOAA s Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data_sub/wind.html. Evaluations will be presented on the impact of the HIRAD instrument on H*Wind analyses, both in terms of adding it to the full suite of current measurements, as well as using it to replace instrument(s) that may not be functioning at the future time the HIRAD instrument is implemented. Also shown will be preliminary results of numerical weather prediction OSSEs in which the impact of the addition of HIRAD observations to the initial state

  18. Simulation of the Impact of New Aircraft- and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses and Numerical Forecasts

    NASA Technical Reports Server (NTRS)

    Miller, Timothy; Atlas, Robert; Black, Peter; Buckley, Courtney; Chen, Shuyi; Hood, robbie; Johnson, James; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric; Krishnamurti, T. N.; Inglish, Cerese; Amarin, Ruba; Al-Nimri, Salem

    2008-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the realtime airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airborne Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath ( 3 x the aircraft altitude). The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a detailed numerical model, and those results are used to construct H*Wind analyses. The H*Wind analysis, a product of the Hurricane Research Division of NOAA s Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data_sub/wind.html. Evaluations will be presented on the impact of the HIRAD instrument on H*Wind analyses, both in terms of adding it to the full suite of current measurements, as well as using it to replace instrument(s) that may not be functioning at the future time the HIRAD instrument is deployed. Plans to demonstrate the potential for HIRAD to improve numerical weather prediction of hurricanes will also be presented.

  19. Aircraft measurements of BrO, IO, glyoxal, NO2, H2O, O2-O2 and aerosol extinction profiles in the tropics: comparison with aircraft-/ship-based in situ and lidar measurements

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-05-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4) were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

  20. Aircraft Measurements of BrO, IO, Glyoxal, NO2, H2O, O2-O2 and Aerosol Extinction Profiles in the Tropics: Comparison with Aircraft-/Ship-Based in Situ and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-01-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4/ were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAXDOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/ National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

  1. Clear Sky Column Closure Studies of Urban-Marine and Mineral-Dust Aerosols Using Aircraft, Ship, Satellite and Ground-Based Measurements in ACE-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Russell, Philip B.; Livingston, John M.; Gasso, Santiago; Hegg, Dean A.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Oestroem, Elisabeth; Noone, Kevin J.; Durkee, Philip A.; Jonsson, Haflidi H.; Welton, Ellsworth J.; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paola; Andreae, Meinrat O.; Kapustin, Vladimir N.; Bates, Timothy S.; Quinn, Patricia K.

    2000-01-01

    As part of the second Aerosol Characterization Experiment (ACE-2), European urban-marine and African mineral-dust aerosols were measured aboard the Pelican aircraft, the Research Vessel Vodyanitskiy from the ground and from satellites.

  2. Solar irradiance measurements from a research aircraft.

    PubMed

    Thekaekara, M P; Kruger, R; Duncan, C H

    1969-08-01

    Measurements of the solar constant and solar spectrum were made from a research aircraft flying at 11.58 km, above almost all of the highly variable and absorbing constituents of the atmosphere. A wide range of solar zenith angles was covered during six flights for over 14 h of observation. Results are presented from nine different instruments which complemented each other in measuring techniques and wavelength range and were calibrated and operated by different experimenters. A new value of the solar constant, 135.1 mW cm(-2), has been derived, as well as a revised solar spectral irradiance curve for zero air mass.

  3. Tissue equivalent proportional counter microdosimetry measurements utililzed aboard aircraft and in accelerator based space radiation shielding studies

    NASA Astrophysics Data System (ADS)

    Gersey, Brad; Wilkins, Richard

    The space radiation environment presents a potential hazard to the humans, electronics and materials that are exposed to it. Particle accelerator facilities such as the NASA Space Ra-diation Laboratory (NSRL) and Loma Linda University Medical Center (LLUMC) provide particle radiation of specie and energy within the range of that found in the space radiation environment. Experiments performed at these facilities determine various endpoints for bio-logical, electronic and materials exposures. A critical factor in the performance of rigorous scientific studies of this type is accurate dosimetric measurements of the exposures. A Tissue Equivalent Proportional Counter (TEPC) is a microdosimeter that may be used to measure absorbed dose, average quality factor (Q) and dose equivalent of the particle beam utilized in these experiments. In this work, results from a variety of space radiation shielding studies where a TEPC was used to perform dosimetry in the particle beam will be presented. These results compare the absorbed dose and dose equivalent measured downstream of equal density thicknesses of stan-dard and multifunctional shielding materials. The standard materials chosen for these shielding studies included High-Density Polyethylene (HDPE) and aluminum alloy, while the multifunc-tional materials included carbon composite infused with single walled carbon nanotubes. High energy particles including proton, silicon and iron nuclei were chosen as the incident radia-tion for these studies. Further, TEPC results from measurements taken during flights aboard ER-2 and KC-135 aircraft will also be discussed. Results from these flight studies include TEPC measurements for shielded and unshielded conditions as well as the effect of vibration and electromagnetic exposures on the TEPC operation. The data selected for presentation will highlight the utility of the TEPC in space radiation studies, and in shielding studies in particular. The lineal energy response function of the

  4. Continuous measurement of aircraft wing icing

    NASA Technical Reports Server (NTRS)

    Yao, Stephen S. C.

    1994-01-01

    Ice formation on the wings of aircraft is a problem that has plagued air travel since its inception. Several recent incidents have been attributed to ice formation on the lifting surfaces of wings. This paper describes a SBIR Phase 1 research effort on the use of small flat dielectric sensors in detecting a layer of ice above the sensor. The sensors are very small, lightweight, and inexpensive. The electronics package that controls the sensor is also small, and could be even smaller using commonly available miniaturization technologies. Thus, several sensors could be placed on a surface such that a representative ice thickness profile could be measured. The benefits offered by developing this technology go beyond the safety improvements realized by monitoring ice formation on the wings of an aircraft. Continuous monitoring of anti-icing fluid concentrations on the ground would warn the pilot of impending fluid failure as well as allowing the stations to use less de-icing solution per aircraft. This in turn would increase the safety of takeoffs and reduce the overall discharge of de-icing solution into the environment, thus reducing the biohazard of the de-icing procedure.

  5. Measurements of neutron radiation in aircraft.

    PubMed

    Vuković, B; Poje, M; Varga, M; Radolić, V; Miklavcić, I; Faj, D; Stanić, D; Planinić, J

    2010-12-01

    Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21° to 58°; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was Ḣ(n)=5.9 μSv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of Ḣ(f)=1.4 μSv/h.

  6. Knowledge-based scheduling of arrival aircraft

    NASA Technical Reports Server (NTRS)

    Krzeczowski, K.; Davis, T.; Erzberger, H.; Lev-Ram, I.; Bergh, C.

    1995-01-01

    A knowledge-based method for scheduling arrival aircraft in the terminal area has been implemented and tested in real-time simulation. The scheduling system automatically sequences, assigns landing times, and assigns runways to arrival aircraft by utilizing continuous updates of aircraft radar data and controller inputs. The scheduling algorithms is driven by a knowledge base which was obtained in over two thousand hours of controller-in-the-loop real-time simulation. The knowledge base contains a series of hierarchical 'rules' and decision logic that examines both performance criteria, such as delay reduction, as well as workload reduction criteria, such as conflict avoidance. The objective of the algorithms is to devise an efficient plan to land the aircraft in a manner acceptable to the air traffic controllers. This paper will describe the scheduling algorithms, give examples of their use, and present data regarding their potential benefits to the air traffic system.

  7. Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, M. J.; Bravo-Aranda, J. A.; Baumgardner, D.; Guerrero-Rascado, J. L.; Pérez-Ramírez, D.; Navas-Guzmán, F.; Veselovskii, I.; Lyamani, H.; Valenzuela, A.; Olmo, F. J.; Titos, G.; Andrey, J.; Chaikovsky, A.; Dubovik, O.; Gil-Ojeda, M.; Alados-Arboledas, L.

    2015-09-01

    In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the

  8. Accurate aircraft wind measurements using the global positioning system (GPS)

    SciTech Connect

    Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J.

    1996-11-01

    High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.

  9. Review of measurement and testing problems. [of aircraft emissions

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Good instrumentation was required to obtain reliable and repeatable baseline data. Problems that were encountered in developing such a total system were: (1) accurate airflow measurement, (2) precise fuel flow measurement, and (3) the instrumentation used for pollutant measurement was susceptible to frequent malfunctions. Span gas quality had a significant effect on emissions test results. The Spindt method was used in the piston aircraft emissions program. The Spindt method provided a comparative computational procedure for fuel/air ratio based on measured emissions concentrations.

  10. Aircraft crew radiation workplaces: comparison of measured and calculated ambient dose equivalent rate data using the EURADOS in-flight radiation data base.

    PubMed

    Beck, Peter; Bartlett, David; Lindborg, Lennart; McAulay, Ian; Schnuer, Klaus; Schraube, Hans; Spurny, Frantisek

    2006-01-01

    In May 2000, the chairman of the European Radiation Dosimetry Group (EURADOS) invited a number of experts with experience of cosmic radiation dosimetry to form a working group (WG 5) on aircraft crew dosimetry. Three observers from the Article 31 Group of Experts as well as one observer from the Joint Aviation Authorities (JAA) were also appointed. The European Commission funded the meetings. Full meetings were organised in January 2001 and in November 2001. An editorial group, who are the authors of this publication, started late in 2002 to finalise a draft report, which was submitted to the Article 31 Group of Experts in June 2003. The methods and data reported are the product of the work of 26 research institutes from the EU, USA and Canada. Some of the work was supported by contracts with the European Commission, Directorate General XII, Science, Research and Development. A first overview of the EC report was published late in 2004. In this publication we focus on a comparison of measured and calculated ambient dose rate data using the EURADOS In-Flight Data Base. The evaluation of results obtained by different methods and groups, and comparison of measurement results and the results of calculations were performed in terms of the operational quantity ambient dose equivalent, H*(10). Aspects of measurement uncertainty are reported also. The paper discusses the estimation of annual doses for given flight hours and gives an outline of further research needed in the field of aircraft crew dosimetry, such as the influence of solar particle events.

  11. Laser-based air data system for aircraft control using Raman and elastic backscatter for the measurement of temperature, density, pressure, moisture, and particle backscatter coefficient.

    PubMed

    Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

    2012-01-10

    Flight safety in all weather conditions demands exact and reliable determination of flight-critical air parameters. Air speed, temperature, density, and pressure are essential for aircraft control. Conventional air data systems can be impacted by probe failure caused by mechanical damage from hail, volcanic ash, and icing. While optical air speed measurement methods have been discussed elsewhere, in this paper, a new concept for optically measuring the air temperature, density, pressure, moisture, and particle backscatter is presented, being independent on assumptions on the atmospheric state and eliminating the drawbacks of conventional aircraft probes by providing a different measurement principle. The concept is based on a laser emitting laser pulses into the atmosphere through a window and detecting the signals backscattered from a fixed region just outside the disturbed area of the fuselage flows. With four receiver channels, different spectral portions of the backscattered light are extracted. The measurement principle of air temperature and density is based on extracting two signals out of the rotational Raman (RR) backscatter signal of air molecules. For measuring the water vapor mixing ratio-and thus the density of the moist air-a water vapor Raman channel is included. The fourth channel serves to detect the elastic backscatter signal, which is essential for extending the measurements into clouds. This channel contributes to the detection of aerosols, which is interesting for developing a future volcanic ash warning system for aircraft. Detailed and realistic optimization and performance calculations have been performed based on the parameters of a first prototype of such a measurement system. The impact and correction of systematic error sources, such as solar background at daytime and elastic signal cross talk appearing in optically dense clouds, have been investigated. The results of the simulations show the high potential of the proposed system for

  12. Laser-based air data system for aircraft control using Raman and elastic backscatter for the measurement of temperature, density, pressure, moisture, and particle backscatter coefficient.

    PubMed

    Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

    2012-01-10

    Flight safety in all weather conditions demands exact and reliable determination of flight-critical air parameters. Air speed, temperature, density, and pressure are essential for aircraft control. Conventional air data systems can be impacted by probe failure caused by mechanical damage from hail, volcanic ash, and icing. While optical air speed measurement methods have been discussed elsewhere, in this paper, a new concept for optically measuring the air temperature, density, pressure, moisture, and particle backscatter is presented, being independent on assumptions on the atmospheric state and eliminating the drawbacks of conventional aircraft probes by providing a different measurement principle. The concept is based on a laser emitting laser pulses into the atmosphere through a window and detecting the signals backscattered from a fixed region just outside the disturbed area of the fuselage flows. With four receiver channels, different spectral portions of the backscattered light are extracted. The measurement principle of air temperature and density is based on extracting two signals out of the rotational Raman (RR) backscatter signal of air molecules. For measuring the water vapor mixing ratio-and thus the density of the moist air-a water vapor Raman channel is included. The fourth channel serves to detect the elastic backscatter signal, which is essential for extending the measurements into clouds. This channel contributes to the detection of aerosols, which is interesting for developing a future volcanic ash warning system for aircraft. Detailed and realistic optimization and performance calculations have been performed based on the parameters of a first prototype of such a measurement system. The impact and correction of systematic error sources, such as solar background at daytime and elastic signal cross talk appearing in optically dense clouds, have been investigated. The results of the simulations show the high potential of the proposed system for

  13. Guide to measurement of winds with instrumented aircraft

    NASA Technical Reports Server (NTRS)

    Frost, Walter; Paige, Terry S.; Nelius, Andrew E.

    1991-01-01

    Aircraft measurement techniques are reviewed. Review of past and present applications of instrument aircraft to atmospheric observations is presented. Questions to be answered relative to measuring mean wind profiles as contrasted to turbulence measurements are then addressed. Requirements of instrumentation and accuracy, data reduction, data acquisition, and theoretical and certainty analysis are considered.

  14. Vision-based aircraft guidance

    NASA Technical Reports Server (NTRS)

    Menon, P. K.

    1993-01-01

    Early research on the development of machine vision algorithms to serve as pilot aids in aircraft flight operations is discussed. The research is useful for synthesizing new cockpit instrumentation that can enhance flight safety and efficiency. With the present work as the basis, future research will produce low-cost instrument by integrating a conventional TV camera together with off-the=shelf digitizing hardware for flight test verification. Initial focus of the research will be on developing pilot aids for clear-night operations. Latter part of the research will examine synthetic vision issues for poor visibility flight operations. Both research efforts will contribute towards the high-speed civil transport aircraft program. It is anticipated that the research reported here will also produce pilot aids for conducting helicopter flight operations during emergency search and rescue. The primary emphasis of the present research effort is on near-term, flight demonstrable technologies. This report discusses pilot aids for night landing and takeoff and synthetic vision as an aid to low visibility landing.

  15. Acoustic measurements of F-16 aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-16 aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that no sonic fatigue problems are anticipated with the F-16 aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-16 aircraft water cooled hush house at Hill AFB, but were increased over that measured during ground run up. It was recommended that the acoustic loads measured in this program should be specified in the structural design criteria for aircraft which will be subjected to hush house operation or defining requirements for associated equipment.

  16. A Comparison of Aircraft and Ground-Based Measurements at Mauna Loa Observatory, Hawaii, During GTE PEM-West and MLOPEX 2

    NASA Technical Reports Server (NTRS)

    Atlas, E.; Ridley, B.; Walega, J.; Greenberg, J.; Kok, G.; Staffelbach, T.; Schauffler, S.; Lind, J.; Huebler, G.; Norton, R.

    1996-01-01

    During October 19-20, 1991, one flight of the NASA Global Tropospheric Experiment (GTE) Pacific Exploratory Mission (PEM-West A) mission was conducted near Hawaii as an intercomparison with ground-based measurements of the Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2) and the NOAA Climate Modeling and Diagnostics Laboratory (CMDL). Ozone, reactive nitrogen species, peroxides, hydrocarbons, and halogenated hydrocarbons were measured by investigators aboard the DC-8 aircraft and at the ground site. Lidar cross sections of ozone revealed a complex air mass structure near the island of Hawaii which was evidenced by large variation in some trace gas mixing ratios. This variation limited the time and spatial scales for direct measurement intercomparisons. Where differences occurred between measurements in the same air masses, the intercomparison suggested that biases for some trace gases was due to different calibration scales or, in some cases, instrumental or sampling biases. Relatively large uncertainties were associated with those trace gases present in the low parts per trillion by volume range. Trace gas correlations were used to expand the scope of the intercomparison to identify consistent trends between the different data sets.

  17. European measurements of aircraft crew exposure to cosmic radiation.

    PubMed

    Menzel, H G; O'Sullivan, D; Beck, P; Bartlett, D

    2000-11-01

    For more than 5 y, the European Commission has supported research into scientific and technical aspects of cosmic-ray dosimetry at flight altitudes in civil radiation. This has been in response to legislation to regard exposure of aircraft crew as occupational, following the recommendations of the International Commission on Radiological Protection in Publication 60. The response to increased public interest and concern, and in anticipation of European and national current work, within a total of three multi-national, multi-partner research contracts, is based on a comprehensive approach including measurements with dosimetric and spectrometric instruments during flights, at high-mountain altitudes, and in a high-energy radiation reference field at CERN, as well as cosmic-ray transport calculations. The work involves scientists in the fields of neutron physics, cosmic-ray physics, and general dosimetry. A detailed set of measurements has been obtained by employing a wide range of detectors on several routes, both on subsonic and supersonic aircraft. Many of the measurements were made simultaneously by several instruments allowing the intercomparison of results. This paper presents a brief overview of results obtained. It demonstrates that the knowledge about radiation fields and on exposure data has been substantially consolidated and that the available data provide an adequate basis for dose assessments of aircraft crew, which will be legally required in the European Union after 13 May 2000.

  18. A comparative study of aerosol microphysical properties retrieved from ground-based remote sensing and aircraft in situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    José Granados-Muñoz, María; Bravo-Aranda, Juan Antonio; Baumgardner, Darrel; Guerrero-Rascado, Juan Luis; Pérez-Ramírez, Daniel; Navas-Guzmán, Francisco; Veselovskii, Igor; Lyamani, Hassan; Valenzuela, Antonio; José Olmo, Francisco; Titos, Gloria; Andrey, Javier; Chaikovsky, Anatoli; Dubovik, Oleg; Gil-Ojeda, Manuel; Alados-Arboledas, Lucas

    2016-03-01

    In this work we present an analysis of aerosol microphysical properties during a mineral dust event taking advantage of the combination of different state-of-the-art retrieval techniques applied to active and passive remote sensing measurements and the evaluation of some of those techniques using independent data acquired from in situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak at the Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on 27 June 2011. Column-integrated properties are provided by sun- and star-photometry, which allows for a continuous evaluation of the mineral dust optical properties during both day and nighttime. Both the linear estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during nighttime. LIRIC retrievals reveal the presence of dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 µm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in situ measurements. This study presents for the first time a comparison of the total volume concentration retrieved with LIRIC with independent in situ measurements, obtaining agreement within

  19. Preliminary measurements of aircraft airframe noise with the NASA CV-990 aircraft

    NASA Technical Reports Server (NTRS)

    White, K. C.; Lasagna, P. L.; Putnam, T. W.

    1976-01-01

    Flight tests were conducted in a CV-990 jet transport with engines at idle power to investigate aircraft airframe noise. Test results showed that airframe noise was measured for the aircraft in the landing configuration. The results agreed well with the expected variation with the fifth power of velocity. For the aircraft in the clean configuraton, it was concluded that airframe noise was measured only at higher airspeeds with engine idle noise present at lower speeds. The data show that landing gear and flaps make a significant contribution to airframe noise.

  20. A Fiber-Optic Aircraft Lightning Current Measurement Sensor

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2013-01-01

    A fiber-optic current sensor based on the Faraday Effect is developed for aircraft installations. It can measure total lightning current amplitudes and waveforms, including continuing current. Additional benefits include being small, lightweight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate in presence of magnetic field in the direction of light propagation. Measuring the total induced light polarization change yields the total current enclosed. The system operates at 1310nm laser wavelength and can measure approximately 300 A - 300 kA, a 60 dB range. A reflective polarimetric scheme is used, where the light polarization change is measured after a round-trip propagation through the fiber. A two-detector setup measures the two orthogonal polarizations for noise subtraction and improved dynamic range. The current response curve is non-linear and requires a simple spline-fit correction. Effects of high current were achieved in laboratory using combinations of multiple fiber and wire loops. Good result comparisons against reference sensors were achieved up to 300 kA. Accurate measurements on a simulated aircraft fuselage and an internal structure illustrate capabilities that maybe difficult with traditional sensors. Also tested at a commercial lightning test facility from 20 kA to 200 kA, accuracy within 3-10% was achieved even with non-optimum setups.

  1. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1973-01-01

    A hygrometer for water vapor measurements from an aircraft has been developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on NASA and USAF aircraft. Water vapor measurements were conducted up to 40,000 feet with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 feet.

  2. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1974-01-01

    A hygrometer for water vapor measurements from an aircraft was developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on the NASA Convair 990 and on a USAF B-57 aircraft. Water vapor measurements from the Convair 990 were conducted up to 40,000 ft with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 ft.

  3. Aircraft body-axis rotation measurement system

    NASA Technical Reports Server (NTRS)

    Cowdin, K. T. (Inventor)

    1983-01-01

    A two gyro four gimbal attitude sensing system having gimbal lock avoidance is provided with continuous azimuth information, rather than roll information, relative to the magnetic cardinal headings while in near vertical attitudes to allow recovery from vertical on a desired heading. The system is comprised of a means for stabilizing an outer roll gimbal that is common to a vertical gyro and a directional gyro with respect to the aircraft platform which is being angularly displaced about an axis substantially parallel to the outer roll gyro axis. A means is also provided for producing a signal indicative of the magnitude of such displacement as an indication of aircraft heading. Additional means are provided to cause stabilization of the outer roll gimbal whenever the pitch angle of the aircraft passes through a threshold prior to entering vertical flight and destabilization of the outer roll gimbal upon passing through the threshold when departing vertical flight.

  4. Instrumentation of sampling aircraft for measurement of launch vehicle effluents

    NASA Technical Reports Server (NTRS)

    Wornom, D. E.; Woods, D. C.; Thomas, M. E.; Tyson, R. W.

    1977-01-01

    An aircraft was selected and instrumented to measure effluents emitted from large solid propellant rockets during launch activities. The considerations involved in aircraft selection, sampling probes, and instrumentation are discussed with respect to obtaining valid airborne measurements. Discussions of the data acquisition system used, the instrument power system, and operational sampling procedures are included. Representative measurements obtained from an actual rocket launch monitoring activity are also presented.

  5. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  6. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata,Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor's accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  7. Measuring Wildfires From Aircraft And Satellites

    NASA Technical Reports Server (NTRS)

    Brass, J. A.; Arvesen, J. C.; Ambrosia, V. G.; Riggan, P. J.; Meyers, J. S.

    1991-01-01

    Aircraft and satellite systems yield wide-area views, providing total coverage of affected areas. System developed for use aboard aircraft includes digital scanner that records data in 12 channels. Transmits data to ground station for immediate use in fighting fires. Enables researchers to estimate gaseous and particulate emissions from fires. Provides information on temperatures of flame fronts and soils, intensities and rate of spread of fires, characteristics of fuels and smoke plumes, energy-release rates, and concentrations and movements of trace gases. Data relates to heating and cooling of soils, loss of nutrients, and effects on atmospheric, terrestrial, and aquatic systems.

  8. Dynamic Modeling Accuracy Dependence on Errors in Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    A nonlinear simulation of the NASA Generic Transport Model was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of dynamic models identified from flight data. Measurements from a typical system identification maneuver were systematically and progressively deteriorated and then used to estimate stability and control derivatives within a Monte Carlo analysis. Based on the results, recommendations were provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using other flight conditions, parameter estimation methods, and a full-scale F-16 nonlinear aircraft simulation were compared with these recommendations.

  9. Mother-of-pearl cloud particle size and composition from aircraft-based photography of coloration and lidar measurements.

    PubMed

    Reichardt, Jens; Reichardt, Susanne; Hostetler, Chris A; Lucker, Patricia L; McGee, Thomas J; Twigg, Laurence W; Dörnbrack, Andreas; Schoeberl, Mark R; Yang, Ping

    2015-02-01

    During a Stratospheric Aerosol and Gas (SAGE)-III Ozone Loss and Validation Experiment (SOLVE)-II science flight on 4 February 2003, a mother-of-pearl cloud over Iceland was underflown by the NASA DC-8 and measured with the lidars onboard. In addition, color photos were taken during the approach. Aided by extensive modeling of cloud coloration, the main results of the analysis of this unique data set are: (1) the polar stratospheric cloud was mountain wave-induced and of type II; (2) the spectacular color display was caused by ice particles with sizes around 2 μm. PMID:25967820

  10. Mother-of-pearl cloud particle size and composition from aircraft-based photography of coloration and lidar measurements.

    PubMed

    Reichardt, Jens; Reichardt, Susanne; Hostetler, Chris A; Lucker, Patricia L; McGee, Thomas J; Twigg, Laurence W; Dörnbrack, Andreas; Schoeberl, Mark R; Yang, Ping

    2015-02-01

    During a Stratospheric Aerosol and Gas (SAGE)-III Ozone Loss and Validation Experiment (SOLVE)-II science flight on 4 February 2003, a mother-of-pearl cloud over Iceland was underflown by the NASA DC-8 and measured with the lidars onboard. In addition, color photos were taken during the approach. Aided by extensive modeling of cloud coloration, the main results of the analysis of this unique data set are: (1) the polar stratospheric cloud was mountain wave-induced and of type II; (2) the spectacular color display was caused by ice particles with sizes around 2 μm.

  11. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment

    NASA Technical Reports Server (NTRS)

    Smith, William L., Jr.; Charlock, Thomas; Wielicki, Bruce; Kahn, Ralph; Martins, J. Vanderlei; Gatebe, Charles; Hobbs, Peter V.; Purgold, G. Carl; Redemann, Jens; Remer, Lorraine

    2004-01-01

    NASA has developed an Earth Observing System (EOS) consisting of a series of satellites designed to study global change from space. The EOS flagship is the EOS TERRA satellite, launched in December 1999, equipped with five unique sensors to monitor and study the Earth s heat budget and many of the key controlling variables governing the Earth's climate system. CLAMS, the Chesapeake Lighthouse and Aircraft Measurements for Satellites field campaign was conducted from NASA Wallops Flight Facility and successfully executed over the middle Atlantic eastern seaboard from July 10 August 2, 2001. CLAMS is primarily a shortwave closure experiment designed to validate and improve EOS TERRA satellite data products being derived from three sensors: CERES (Clouds and Earth's Radiant Energy System), MISR (Multi-angle Imaging Spectro-Radiometer) and MODIS (MODerate Resolution Imaging Spectroradiometer). CLAMS is jointly sponsored by the CERES, MISR and MODIS instrument teams and the NASA GEWEX Global Aerosol Climatology Project (GACP). CLAMS primary objectives are to validate satellite-based retrievals of aerosol properties and vertical profiles of radiative flux, temperature and water vapor. Central to CLAMS measurement strategy is the Chesapeake Lighthouse, a stable sea platform located in the Atlantic Ocean, 13 miles east of Virginia Beach near the mouth of the Chesapeake Bay and the site of an ongoing CERES Ocean Validation Experiment (COVE). Six research aircraft were deployed to make detailed measurements of the atmosphere and ocean surface in the vicinity of COVE, over the surrounding ocean, over nearby NOAA buoys and over a few land sites. The measurements are used to validate and provide ground truth for simultaneous products being derived from TERRA data, a key step toward an improved understanding and ability to predict changes in the Earth's climate. One of the two CERES instruments on-board TERRA was programmed for Rotating Azimuth Plane Scans (RAPS) during CLAMS

  12. Ultrasonic Measurement of Aircraft Strut Hydraulic Fluid Level

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.

    2002-01-01

    An ultrasonic method is presented for non-intrusively measuring hydraulic fluid level in aircraft struts in the field quickly and easily without modifying the strut or aircraft. The technique interrogates the strut with ultrasonic waves generated and received by a removable ultrasonic transducer hand-held on the outside of the strut in a fashion that is in the presence or absence of hydraulic fluid inside the strut. This technique was successfully demonstrated on an A-6 aircraft strut on the carriage at the Aircraft Landing Dynamics Research Facility at NASA Langley Research Center. Conventional practice upon detection of strut problem symptoms is to remove aircraft from service for extensive maintenance to determine fluid level. No practical technique like the method presented herein for locating strut hydraulic fluid level is currently known to be used.

  13. Using an A-10 Aircraft for Airborne measurements of TGFs

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.; Christian, Hugh, J.; Blakeslee, Richard J.; Grove, J. Eric; Chektman, Alexandre; Jonsson, Haflidi; Detwiler, Andrew G.

    2012-01-01

    Plans are underway to convert an A-10 combat attack aircraft into a research aircraft for thunderstorm research. This aircraft would be configured and instrumented for flights into large, convective thunderstorms. It would have the capabilities of higher altitude performance and protection for thunderstorm conditions that exceed those of aircraft now in use for this research. One area of investigation for this aircraft would be terrestrial gamma ]ray flashes (TGFs), building on the pioneering observations made by the Airborne Detector for Energetic Lightning Emissions (ADELE) project several years ago. A new and important component of the planned investigations are the continuous, detailed correlations of TGFs with the electric fields near the aircraft, as well as detailed measurements of nearby lightning discharges. Together, the x-and gamma-radiation environments, the electric field measurements, and the lightning observations (all measured on microsecond timescales) should provide new insights into this TGF production mechanism. The A -10 aircraft is currently being modified for thunderstorm research. It is anticipated that the initial test flights for this role will begin next year.

  14. Improved atmospheric trace gas measurements with an aircraft-based tandem mass spectrometer: Ion identification by mass-selected fragmentation studies

    NASA Astrophysics Data System (ADS)

    Reiner, Thomas; MöHler, Ottmar; Arnold, Frank

    1998-12-01

    We have built and employed an aircraft-borne triple quadrupole mass spectrometer (TQMS) for fragmentation studies of mass-selected ions in the upper troposphere and lower stratosphere. The fragmentation studies included both ambient and artificially produced ions relevant for the measurement of atmospheric trace gases by ion molecule reaction mass spectrometry (IMRMS) and led to an unambiguous identification of the chemical composition of important ions used for IMRMS measurements. Among these are the product ions of ion molecule reactions of CO3-(H2O)n and H3O+(H2O)n ions with HNO3, SO2, acetone, HCN, and methyl cyanide. These reactions have been studied in the laboratory, and ions having the same masses as the expected product ions have been previously observed in atmospheric IMRMS spectra. The present fragmentation studies are the first to actually identify the chemical composition of these ions during aircraft measurements in the upper troposphere and lower stratosphere and demonstrate that these ions can reliably be used for atmospheric trace gas measurements. Furthermore, the fragmentation studies gave indications for the existence and the possible identification of previously unknown ions. Among these the tentative identification of CO3-H2O2 offers the possibility for sensitive measurements of H2O2 by IMRMS. The fragmentation studies were accompanied by IMRMS measurements of atmospheric trace gases using the TQMS. Altitude profiles of HNO3, SO2, and lower limits for H2O2 are shown.

  15. Analysis of Aircraft Control Performance using a Fuzzy Rule Base Representation of the Cooper-Harper Aircraft Handling Quality Rating

    NASA Technical Reports Server (NTRS)

    Tseng, Chris; Gupta, Pramod; Schumann, Johann

    2006-01-01

    The Cooper-Harper rating of Aircraft Handling Qualities has been adopted as a standard for measuring the performance of aircraft since it was introduced in 1966. Aircraft performance, ability to control the aircraft, and the degree of pilot compensation needed are three major key factors used in deciding the aircraft handling qualities in the Cooper- Harper rating. We formulate the Cooper-Harper rating scheme as a fuzzy rule-based system and use it to analyze the effectiveness of the aircraft controller. The automatic estimate of the system-level handling quality provides valuable up-to-date information for diagnostics and vehicle health management. Analyzing the performance of a controller requires a set of concise design requirements and performance criteria. Ir, the case of control systems fm a piloted aircraft, generally applicable quantitative design criteria are difficult to obtain. The reason for this is that the ultimate evaluation of a human-operated control system is necessarily subjective and, with aircraft, the pilot evaluates the aircraft in different ways depending on the type of the aircraft and the phase of flight. In most aerospace applications (e.g., for flight control systems), performance assessment is carried out in terms of handling qualities. Handling qualities may be defined as those dynamic and static properties of a vehicle that permit the pilot to fully exploit its performance in a variety of missions and roles. Traditionally, handling quality is measured using the Cooper-Harper rating and done subjectively by the human pilot. In this work, we have formulated the rules of the Cooper-Harper rating scheme as fuzzy rules with performance, control, and compensation as the antecedents, and pilot rating as the consequent. Appropriate direct measurements on the controller are related to the fuzzy Cooper-Harper rating system: a stability measurement like the rate of change of the cost function can be used as an indicator if the aircraft is under

  16. Aircraft detection based on probability model of structural elements

    NASA Astrophysics Data System (ADS)

    Chen, Long; Jiang, Zhiguo

    2014-11-01

    Detecting aircrafts is important in the field of remote sensing. In past decades, researchers used various approaches to detect aircrafts based on classifiers for overall aircrafts. However, with the development of high-resolution images, the internal structures of aircrafts should also be taken into consideration now. To address this issue, a novel aircrafts detection method for satellite images based on probabilistic topic model is presented. We model aircrafts as the connected structural elements rather than features. The proposed method contains two major steps: 1) Use Cascade-Adaboost classier to identify the structural elements of aircraft firstly. 2) Connect these structural elements to aircrafts, where the relationships between elements are estimated by hierarchical topic model. The model places strict spatial constraints on structural elements which can identify differences between similar features. The experimental results demonstrate the effectiveness of the approach.

  17. Measurement of Phase Difference for Micromachined Gyros Driven by Rotating Aircraft

    PubMed Central

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-01-01

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%. PMID:23966195

  18. Measurement of phase difference for micromachined gyros driven by rotating aircraft.

    PubMed

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-08-21

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%.

  19. Aircraft Wake Vortex Measurement with Coherent Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Wu, Songhua; Liu, Bingyi; Liu, Jintao

    2016-06-01

    Aircraft vortices are generated by the lift-producing surfaces of the aircraft. The variability of near-surface conditions can change the drop rate and cause the cell of the wake vortex to twist and contort unpredictably. The pulsed Coherent Doppler Lidar Detection and Ranging is an indispensable access to real aircraft vortices behavior which transmitting a laser beam and detecting the radiation backscattered by atmospheric aerosol particles. Experiments for Coherent Doppler Lidar measurement of aircraft wake vortices has been successfully carried out at the Beijing Capital International Airport (BCIA). In this paper, the authors discuss the Lidar system, the observation modes carried out in the measurements at BCIA and the characteristics of vortices.

  20. Acoustic measurements of F-4E aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The primary purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-4E aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that sonic fatigue problems are anticipated with the F-4E aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-4E aircraft water cooled hush house at Hill AFB in the lower frequencies, but were increased over that measured during ground run up on some areas of the aircraft. It was recommended that the acoustic loads measured in this program should be specified in the structural design criteria for aircraft which will be subjected to hush house operation or defining requirements for associated equipment. Recommendations were also made to increase the fatigue life of the aft fuselage.

  1. Immunity-Based Aircraft Fault Detection System

    NASA Technical Reports Server (NTRS)

    Dasgupta, D.; KrishnaKumar, K.; Wong, D.; Berry, M.

    2004-01-01

    In the study reported in this paper, we have developed and applied an Artificial Immune System (AIS) algorithm for aircraft fault detection, as an extension to a previous work on intelligent flight control (IFC). Though the prior studies had established the benefits of IFC, one area of weakness that needed to be strengthened was the control dead band induced by commanding a failed surface. Since the IFC approach uses fault accommodation with no detection, the dead band, although it reduces over time due to learning, is present and causes degradation in handling qualities. If the failure can be identified, this dead band can be further A ed to ensure rapid fault accommodation and better handling qualities. The paper describes the application of an immunity-based approach that can detect a broad spectrum of known and unforeseen failures. The approach incorporates the knowledge of the normal operational behavior of the aircraft from sensory data, and probabilistically generates a set of pattern detectors that can detect any abnormalities (including faults) in the behavior pattern indicating unsafe in-flight operation. We developed a tool called MILD (Multi-level Immune Learning Detection) based on a real-valued negative selection algorithm that can generate a small number of specialized detectors (as signatures of known failure conditions) and a larger set of generalized detectors for unknown (or possible) fault conditions. Once the fault is detected and identified, an adaptive control system would use this detection information to stabilize the aircraft by utilizing available resources (control surfaces). We experimented with data sets collected under normal and various simulated failure conditions using a piloted motion-base simulation facility. The reported results are from a collection of test cases that reflect the performance of the proposed immunity-based fault detection algorithm.

  2. Ultraviolet spectrophotometer for measuring columnar atmospheric ozone from aircraft.

    PubMed

    Hanser, F A; Sellers, B; Briehl, D C

    1978-05-15

    An ultraviolet spectrophotometer (UVS) to measure downward solar fluxes from an aircraft or other high altitude platform is described. The UVS uses an ultraviolet diffuser to obtain large angular response with no aiming requirement, a twelve-position filter wheel with narrow (2-nm) and broad (20-nm) bandpass filters, and an ultraviolet photodiode. The columnar atmospheric ozone above the UVS (aircraft) is calculated from the ratios of the measured ultraviolet fluxes. Comparison with some Dobson station measurements gives agreement to 2%. Some UVS measured ozone profiles over the Pacific Ocean for November 1976 are shown to illustrate the instrument's performance.

  3. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  4. Aircraft measurements and analysis of severe storms: 1975 field experiment

    NASA Technical Reports Server (NTRS)

    Sinclair, P. C.

    1976-01-01

    Three aircraft and instrumentation systems were acquired in support of the severe storm surveillance program. The data results indicate that the original concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, dew point, etc., near and within specifically designated severe storms is entirely feasible and has been demonstrated for the first time by this program. This program is unique in that it is designed to be highly mobile in order to move to and/or with the developing storm systems to obtain the necessary measurements. Previous programs have all been fixed to a particular location and therefore have had to wait for the storms to come within their network. The present research is designed around a highly mobile aircraft measurements group in order to maximize the storm cases during the field measurements program.

  5. Water vapor in the lower stratosphere measured from aircraft flight

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.; Guenther, B.; Dunn, P.

    1977-01-01

    Water vapor in the lower stratosphere was measured in situ by two aluminum oxide hygrometers mounted on the nose of an RB57 aircraft. Data were taken nearly continuously from January to May 1974 from an altitude of approximately 11-19 km as the aircraft flew between 70 deg N and 50 deg S over the land areas in the Western Hemisphere. Pseudomeridional cross sections of water vapor and temperature were derived from the flight data and show mixing ratios predominantly between 2 and 4 microg/g with an extreme range of 1-8 microg/g. Measurement precision was estimated by comparing the simultaneously measured values from the two flight hygrometer systems. Accuracy was estimated to be about + or - 40% at 19 km. A height-averaged latitudinal cross section of water vapor indicates symmetry of wet and dry zones. This cross section is compared with other aircraft measurements and relates to meridional circulation models.

  6. IAGOS : operational start of atmospheric measurements on commercial Airbus aircraft

    NASA Astrophysics Data System (ADS)

    Nedelec, P.

    2011-12-01

    AUTHORS : Philippe Nedelec 1, Jean-Pierre Cammas 1, Gilles Athier 1, Damien Boulanger 1, Jean-Marc Cousin 1., Andreas Volz-Thomas 2. 1. Laboratoire d' Aerologie, CNRS and University of Toulouse, Toulouse, France. 2. FZ Jülich, Jülich, Germany The MOZAIC program (http://mozaic.aero.obs-mip.fr) measures atmospheric parameters since August 1994, on board 5 commercial Airbus A340 aircraft operated by European airlines, with about 33 000 flights up to present. Three aircraft are still in operation and a new project has been sponsored by the European Community, and French and German national budgets. This project is called IAGOS for "In-service Aircraft for a Global Observing system" and can be considered as an update of Mozaic systems, increasing the performances and the measuring capacity. Plans are to equip 10-20 aircraft in the coming years to ensure a global coverage of the observations. Instrumentation has been developed by the participating partners and has been certified for installation on commercial passenger aircraft. The basic instrumentation includes O3, CO, H2O and clouds sensors, as well as the position and meteorological parameters acquired by the aircraft. One of the optional equipment can also be installed: NOx or NOy or CO2/CH4 or Aerosols. Data measured during flight are automatically transmitted after aircraft landing to CNRS reception centre in Toulouse, France, and made available to scientist some days later. The installation on a Lufthansa Airbus A340 has been finalised and certified by EASA (European Aviation Safety Agency) on July 7th, 2011 and operations started the following day, with data transmitted every landing to the CNRS centre. We will present technical details of the IAGOS aeronautic installation, measuring instruments of the basic system and some results of the first months of IAGOS operation.

  7. Optical measurements of degradation in aircraft boundary layers

    NASA Technical Reports Server (NTRS)

    Kelsall, D.

    1980-01-01

    Visible wavelength measurements of the degradation of optical beams when transmitted through the thin aerodynamic boundary layers around an aircraft are reviewed. The measured results indicated degradation levels for the KC-135 airplanes between 0.10 to 0.13 lambda increasing to 0.18 lambda (rms wavefront distortion). For the Lear Jet, degradation with a 25 mm diameter optics was roughly 0.07 lambda. The corresponding infinite aperture degradation levels are also calculated. The corresponding measured correlation lengths of roughly 12 mm for the KC-135 aircraft and 6 mm for the Lear Jet scale to roughly 20 and 25 mm, respectively, for infinite apertures. These boundary layer correlation lengths do not appear to reflect the different boundary layer thicknesses on the two different aircraft.

  8. Pilot Workload Measurement and Experience on Supersonic Cruise Aircraft

    NASA Technical Reports Server (NTRS)

    Rezek, T. W.

    1978-01-01

    Aircraft parameters and physiological parameters most indicative of crew workload were investigated. Recommendations were used to form the basis for a continuing study in which variations of the interval between heart beats are used as a measure of nonphysical workload. Preliminary results are presented and current efforts in further defining this physiological measure are outlined.

  9. Comparison of wind and turbulence measurements from Doppler lidar and instrumented aircraft

    NASA Technical Reports Server (NTRS)

    Huang, K. H.; Frost, W.; Ringnes, E. A.

    1985-01-01

    Wind fields were measured with the ground based lidar, NOAA Wave Propagation Laboratory and with the NASA B-57B instrumented aircraft. The remotely sensed winds are compared with the in situ aircraft measurements. Three flight plans were carried out during the two different field programs. At NASA/MSFC the aircraft circled while the lidar scanned conically and the aircraft flew 6 deg approach path along the fixed lidar beam. The aircraft flew an approach along the lidar beam directed south-north (parallel to the mountain range) and a climbout along the lidar beam which alternately shifted east-west (perpendicular to the mountain range). Turbulence intensities and spectra were calculated from the temporal fluctuations in the lidar-measured radial wind speed component. These field tests provided unique sets of data to examine the mean wind and turbulence measurements made by remote sensing instruments. The comparison of aircraft measured turbulence intensities and spectra with lidar time histories of radial wind speed were in good agreement.

  10. Long-term greenhouse gas measurements from aircraft

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Newberger, T.; Chen, H.; Andrews, A.; Kofler, J.; Neff, D.; Tans, P.

    2013-03-01

    In March 2009 the NOAA/ESRL/GMD Carbon Cycle and Greenhouse Gases Group collaborated with the US Coast Guard (USCG) to establish the Alaska Coast Guard (ACG) sampling site, a unique addition to NOAA's atmospheric monitoring network. This collaboration takes advantage of USCG bi-weekly Arctic Domain Awareness (ADA) flights, conducted with Hercules C-130 aircraft from March to November each year. Flights typically last 8 h and cover a large area, traveling from Kodiak up to Barrow, Alaska, with altitude profiles near the coast and in the interior. NOAA instrumentation on each flight includes a flask sampling system, a continuous cavity ring-down spectroscopy (CRDS) carbon dioxide (CO2)/methane (CH4)/carbon monoxide (CO)/water vapor (H2O) analyzer, a continuous ozone analyzer, and an ambient temperature and humidity sensor. Air samples collected in flight are analyzed at NOAA/ESRL for the major greenhouse gases and a variety of halocarbons and hydrocarbons that influence climate, stratospheric ozone, and air quality. We describe the overall system for making accurate greenhouse gas measurements using a CRDS analyzer on an aircraft with minimal operator interaction and present an assessment of analyzer performance over a three-year period. Overall analytical uncertainty of CRDS measurements in 2011 is estimated to be 0.15 ppm, 1.4 ppb, and 5 ppb for CO2, CH4, and CO, respectively, considering short-term precision, calibration uncertainties, and water vapor correction uncertainty. The stability of the CRDS analyzer over a seven-month deployment period is better than 0.15 ppm, 2 ppb, and 4 ppb for CO2, CH4, and CO, respectively, based on differences of on-board reference tank measurements from a laboratory calibration performed prior to deployment. This stability is not affected by variation in pressure or temperature during flight. We conclude that the uncertainty reported for our measurements would not be significantly affected if the measurements were made without in

  11. Holistic aerosol evaluation using synthesized aerosol aircraft measurements

    NASA Astrophysics Data System (ADS)

    Watson-Parris, Duncan; Reddington, Carly; Schutgens, Nick; Stier, Philip; Carslaw, Ken; Liu, Dantong; Allan, James; Coe, Hugh

    2016-04-01

    Despite ongoing efforts there are still large uncertainties in aerosol concentrations and loadings across many commonly used GCMs. This in turn leads to large uncertainties in the contributions of the direct and indirect aerosol forcing on climate. However, constraining these fields using earth observation data, although providing global coverage, is problematic for many reasons, including the large uncertainties in retrieving aerosol loadings. Additionally, the inability to retrieve aerosols in or around cloudy scenes leads to further sampling biases (Gryspeerdt 2015). Many in-situ studies have used regional datasets to attempt to evaluate the model uncertainties, but these are unable to provide an assessment of the models ability to represent aerosols properties on a global scale. Within the Global Aerosol Synthesis and Science Project (GASSP) we have assembled the largest collection of quality controlled, in-situ aircraft observations ever synthesized to a consistent format. This provides a global set of in-situ measurements of Cloud Condensation Nuclei (CCN) and Black Carbon (BC), amongst others. In particular, the large number of vertical profiles provided by this aircraft data allows us to investigate the vertical structure of aerosols across a wide range of regions and environments. These vertical distributions are particularly valuable when investigating the dominant processes above or below clouds where remote sensing data is not available. Here we present initial process-based assessments of the BC lifetimes and vertical distributions of CCN in the HadGEM-UKCA and ECHAM-HAM models using this data. We use point-by-point based comparisons to avoid the sampling issues associated with comparing spatio-temporal aggregations.

  12. Wind shear detection using measurement of aircraft total energy change

    NASA Technical Reports Server (NTRS)

    Joppa, R. G.

    1976-01-01

    Encounters with wind shears are of concern and have caused major accidents, particularly during landing approaches. Changes in the longitudinal component of the wind affect the aircraft by changing its kinetic energy with respect to the air. It is shown that an instrument which will measure and display the rate of change of total energy of the aircraft with respect to the air will give a leading indication of wind shear problems. The concept is outlined and some instrumentation and display considerations are discussed.

  13. Real-time measurements of jet aircraft engine exhaust.

    PubMed

    Rogers, Fred; Arnott, Pat; Zielinska, Barbara; Sagebiel, John; Kelly, Kerry E; Wagner, David; Lighty, JoAnn S; Sarofim, Adel F

    2005-05-01

    Particulate-phase exhaust properties from two different types of ground-based jet aircraft engines--high-thrust and turboshaft--were studied with real-time instruments on a portable pallet and additional time-integrated sampling devices. The real-time instruments successfully characterized rapidly changing particulate mass, light absorption, and polycyclic aromatic hydrocarbon (PAH) content. The integrated measurements included particulate-size distributions, PAH, and carbon concentrations for an entire test run (i.e., "run-integrated" measurements). In all cases, the particle-size distributions showed single modes peaking at 20-40nm diameter. Measurements of exhaust from high-thrust F404 engines showed relatively low-light absorption compared with exhaust from a turboshaft engine. Particulate-phase PAH measurements generally varied in phase with both net particulate mass and with light-absorbing particulate concentrations. Unexplained response behavior sometimes occurred with the real-time PAH analyzer, although on average the real-time and integrated PAH methods agreed within the same order of magnitude found in earlier investigations.

  14. Real-time measurements of jet aircraft engine exhaust.

    PubMed

    Rogers, Fred; Arnott, Pat; Zielinska, Barbara; Sagebiel, John; Kelly, Kerry E; Wagner, David; Lighty, JoAnn S; Sarofim, Adel F

    2005-05-01

    Particulate-phase exhaust properties from two different types of ground-based jet aircraft engines--high-thrust and turboshaft--were studied with real-time instruments on a portable pallet and additional time-integrated sampling devices. The real-time instruments successfully characterized rapidly changing particulate mass, light absorption, and polycyclic aromatic hydrocarbon (PAH) content. The integrated measurements included particulate-size distributions, PAH, and carbon concentrations for an entire test run (i.e., "run-integrated" measurements). In all cases, the particle-size distributions showed single modes peaking at 20-40nm diameter. Measurements of exhaust from high-thrust F404 engines showed relatively low-light absorption compared with exhaust from a turboshaft engine. Particulate-phase PAH measurements generally varied in phase with both net particulate mass and with light-absorbing particulate concentrations. Unexplained response behavior sometimes occurred with the real-time PAH analyzer, although on average the real-time and integrated PAH methods agreed within the same order of magnitude found in earlier investigations. PMID:15991667

  15. Wavelet-based acoustic recognition of aircraft

    SciTech Connect

    Dress, W.B.; Kercel, S.W.

    1994-09-01

    We describe a wavelet-based technique for identifying aircraft from acoustic emissions during take-off and landing. Tests show that the sensor can be a single, inexpensive hearing-aid microphone placed close to the ground the paper describes data collection, analysis by various technique, methods of event classification, and extraction of certain physical parameters from wavelet subspace projections. The primary goal of this paper is to show that wavelet analysis can be used as a divide-and-conquer first step in signal processing, providing both simplification and noise filtering. The idea is to project the original signal onto the orthogonal wavelet subspaces, both details and approximations. Subsequent analysis, such as system identification, nonlinear systems analysis, and feature extraction, is then carried out on the various signal subspaces.

  16. Measurements from aircraft to characterize watersheds

    NASA Technical Reports Server (NTRS)

    Blanchard, B. J.

    1972-01-01

    Remote sensor measurements of the Southern Plains watershed, an 1130 sq mile segment of the Washita River basin in the Texas Panhandle, are discussed. Soil moisture measurements are emphasized, along with rainfall storage capacity of the soil. Indicators of pond water quality, geologic sources of sediment or salt, and rapid methods of mapping seepage are being searched for through remote sensing.

  17. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  18. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.

  19. Ultrasonic techniques for aircraft ice accretion measurement

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.; Lichtenfelts, Fred

    1990-01-01

    Results of tests to measure ice growth in natural (flight) and artificial (icing wind tunnel) icing conditions are presented. Ice thickness is measured using an ultrasonic pulse-echo technique. Two icing regimes, wet and dry ice growth, are identified and the unique ultrasonic signal characteristics associated with these different types of ice growth are described. Ultrasonic measurements of ice growth on cylinders and airfoils exposed to artificial and natural icing conditions are presented. An accuracy of plus or minus 0.5 mm is achieved for ice thickness measurement using the pulse-echo technique. The performance of two-probe type ice detectors is compared to the surface mounted ultrasonic system. The ultrasonically measured ice accretion rates and ice surface condition (wet or dry) are used to compare the heat transfer characteristics for flight and icing wind tunnel environments. In general the heat transfer coefficient is inferred to be higher in the wind tunnel environment, not likely due to higher freestream turbulence levels. Finally, preliminary results of tests to measure ice growth on airfoil using an array of ultrasonic transducers are described. Ice profiles obtained during flight in natural icing conditions are shown and compared with mechanical and stereo image measurements.

  20. Comparison of NOAA-9 ERBE measurements with Cirrus IFO satellite and aircraft measurements

    NASA Technical Reports Server (NTRS)

    Ackerman, Steven A.; Chung, Hyosang; Cox, Stephen K.; Herman, Leroy; Smith, William L.; Wylie, Donald P.

    1990-01-01

    Earth Radiation Budget Experiment (ERBE) measurements onboard the NOAA-9 are compared for consistency with satellite and aircraft measurements made during the Cirrus Intensive Field Observation (IFO) of October 1986. ERBE scene identification is compared with NOAA-9 TIROS Operational Vertical Sounder (TOVS) cloud retrievals; results from the ERBE spectral inversion algorithms are compared with High resolution Interferometer Sounder (HIS) measurements; and ERBE radiant existance measurements are compared with aircraft radiative flux measurements.

  1. Ultrasonic techniques for aircraft ice accretion measurement

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.; Lichtenfelts, Fred

    1988-01-01

    Ultrasonic pulse-echo measurements of ice growth on cylinders and airfoils exposed to both artificial (icing wind tunnel) and natural (flight) icing conditions are presented. An accuracy of + or - 0.5 mm is achieved with the present method. The ultrasonic signal characteristics associated with each of the two types of icing regimes identified, wet and dry ice growth, are discussed. Heat transfer coefficients are found to be higher in the wind tunnel environment than in flight. Results for ice growth on airfoils have also been obtained using an array of ultrasonic transducers. Icing profiles obtained during flight are compared with mechanical and stereo image measurements.

  2. Aircraft attitude measurement using a vector magnetometer

    NASA Technical Reports Server (NTRS)

    Peitila, R.; Dunn, W. R., Jr.

    1977-01-01

    The feasibility of a vector magnetometer system was investigated by developing a technique to determine attitude given magnetic field components. Sample calculations are then made using the earth's magnetic field data acquired during actual flight conditions. Results of these calculations are compared graphically with measured attitude data acquired simultaneously with the magnetic data. The role and possible implementation of various reference angles are discussed along with other pertinent considerations. Finally, it is concluded that the earth's magnetic field as measured by modern vector magnetometers can play a significant role in attitude control systems.

  3. Immunity-Based Accommodation of Aircraft Subsystem Failures

    NASA Astrophysics Data System (ADS)

    Togayev, Adil

    This thesis presents the design, development, and flight-simulation testing of an artificial immune system (AIS) based approach for accommodation of different aircraft subsystem failures. Failure accommodation is considered as part of a complex integrated AIS scheme that contains four major components: failure detection, identification, evaluation, and accommodation. The accommodation part consists of providing compensatory commands to the aircraft under specific abnormal conditions based on previous experience. In this research effort, the possibility of building an AIS allowing the extraction of pilot commands is investigated. The proposed approach is based on structuring the self (nominal conditions) and the non-self (abnormal conditions) within the AIS paradigm, as sets of artificial memory cells (mimicking behavior of T-cells, B-cells, and antibodies) consisting of measurement strings, over pre-defined time windows. Each string is a set of features values at each sample time of the flight including pilot inputs, system states, and other variables. The accommodation algorithm relies on identifying the memory cell that is the most similar to the in-coming measurements. Once the best match is found, control commands corresponding to this match will be extracted from the memory and used for control purposes. The proposed methodology is illustrated through simulation of simple maneuvers at nominal flight conditions, different actuators, and sensor failure conditions. Data for development and demonstration have been collected from West Virginia University 6-degrees-of-freedom motion-based flight simulator. The aircraft model used for this research represents a supersonic fighter which includes model following adaptive control laws based on non-linear dynamic inversion and artificial neural network augmentation. The simulation results demonstrate the possibility of extracting pilot compensatory commands from the self/non-self structure and the capability of the AIS

  4. Water vapor in the lower stratosphere measured from aircraft flight

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.; Guenther, B.; Dunn, P.

    1976-01-01

    Water vapor in the lower stratosphere was measured in situ by two aluminum oxide hygrometers mounted on the nose of an RB57 aircraft. Data were taken nearly continuously from January to May 1974 from an altitude of approximately 11 km to 19 km as the aircraft flew between 70 deg N and 50 deg S over the land areas in the Western Hemisphere. Pseudomeridional cross sections of water vapor and temperature are derived from the flight data and show mixing ratios predominantly between 2 and 4 micron gm/gm with an extreme range of 1 to 8 micron gm/gm. Measurement precision is estimated by comparing the simultaneously measured values from the two flight hygrometer systems. Accuracy is estimated to be about + or - 40 percent at 19 km. A height-averaged latitudinal cross section of water vapor shows symmetry of wet and dry zones.

  5. MISR Browse Images: Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS)

    Atmospheric Science Data Center

    2016-06-13

    ... MISR Browse Images: Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS)   These ... of the region observed during the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign. CLAMS focused on ...

  6. Acoustic measurements of F-15 aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-15 aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that no potential sonic fatigue problems are anticipated with the F-15 aircraft structure during operation in the hush house. However, since these acoustic levels were increased over those measuring during run up on a concrete pad, it is recommended that F-15 equipment qualification levels be checked. The data indicated that the noise field within the hush house is diffuse and that the acoustical energy in the hangar area is radiated from the region between the engine exhaust and the hush house muffler front edge toward the forward part of the hangar.

  7. Dependence of Dynamic Modeling Accuracy on Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations

  8. Measurement of static pressure on aircraft

    NASA Technical Reports Server (NTRS)

    Gracey, William

    1958-01-01

    Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented. Errors due to the position of a static-pressure tube in the flow field of the airplane are given for locations ahead of the fuselage nose, ahead of the wing tip, and ahead of the vertical tail fin. The errors of static-pressure vents on the fuselage of an airplane are also presented. Various methods of calibrating static-pressure installations in flight are briefly discussed.

  9. Long-term greenhouse gas measurements from aircraft

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Newberger, T.; Chen, H.; Andrews, A.; Kofler, J.; Neff, D.; Tans, P.

    2012-10-01

    In March 2009 the NOAA/ESRL/GMD Carbon Cycle and Greenhouse Gases Group collaborated with the US Coast Guard (USCG) to establish the Alaska Coast Guard (ACG) sampling site, a unique addition to NOAA's atmospheric monitoring network. This collaboration takes advantage of USCG bi-weekly Arctic Domain Awareness (ADA) flights, conducted with Hercules C-130 aircraft from March to November each year. NOAA has installed window-replacement inlet plates on two USCG C-130 aircraft and deploys a pallet with NOAA instrumentation on each ADA flight. Flights typically last 8 h and cover a very large area, traveling from Kodiak, AK in the south up to Barrow, AK in the north, and making altitude profiles near the coast as well as in the interior. NOAA instrumentation on each flight includes: a flask sampling system, a continuous CO2/CH4/CO/H2O analyzer, a continuous ozone analyzer, and an ambient temperature and humidity sensor. GPS time and location from the aircraft's navigation system are also collected. Air samples collected in flight are analyzed at NOAA/ESRL for the major greenhouse gases and a variety of halocarbons and hydrocarbons that influence climate, stratospheric ozone, and air quality. Instruments on this aircraft are designed and deployed to be able to collect air samples and data autonomously, so that NOAA personnel visit the site only for installation at the beginning of each season. We present an assessment of the cavity ring-down spectroscopy (CRDS) CO2/CH4/CO/H2O analyzer performance operating on an aircraft over a three-year period. We describe the overall system for making accurate greenhouse gas measurements using a CRDS analyzer on an aircraft with minimal operator interaction. Short and long-term stability of the CRDS analyzer over a seven-month deployment period is better than 0.15 ppm, 2 ppb, and 5 ppb for CO2, CH4, CO respectively, considering differences of on-board reference tank measurements from a laboratory calibration performed prior to

  10. Experimental measurement of structural power flow on an aircraft fuselage

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1989-01-01

    An experimental technique is used to measure the structural power flow through an aircraft fuselage with the excitation near the wing attachment location. Because of the large number of measurements required to analyze the whole of an aircraft fuselage, it is necessary that a balance be achieved between the number of measurement transducers, the mounting of these transducers, and the accuracy of the measurements. Using four transducers mounted on a bakelite platform, the structural intensity vectors at locations distributed throughout the fuselage are measured. To minimize the errors associated with using a four transducers technique the measurement positions are selected away from bulkheads and stiffeners. Because four separate transducers are used, with each transducer having its own drive and conditioning amplifiers, phase errors are introduced in the measurements that can be much greater than the phase differences associated with the measurements. To minimize these phase errors two sets of measurements are taken for each position with the orientation of the transducers rotated by 180 deg and an average taken between the two sets of measurements. Results are presented and discussed.

  11. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore we draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  12. Structureborne noise measurements on a small twin-engine aircraft

    NASA Technical Reports Server (NTRS)

    Cole, J. E., III; Martini, K. F.

    1988-01-01

    Structureborne noise measurements performed on a twin-engine aircraft (Beechcraft Baron) are reported. There are two overall objectives of the test program. The first is to obtain data to support the development of analytical models of the wing and fuselage, while the second is to evaluate effects of structural parameters on cabin noise. Measurements performed include structural and acoustic responses to impact excitation, structural and acoustic loss factors, and modal parameters of the wing. Path alterations include added mass to simulate fuel, variations in torque of bolts joining wing and fuselage, and increased acoustic absorption. Conclusions drawn regarding these measurements are presented.

  13. Probing Emissions of Military Cargo Aircraft: Description of a Joint Field Measurement Program

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.; DeWitt, M.; Spicer, C.; Holdren, M.; Cowen, K.; Harris, B.; Shores, R.; Hashmonay, R.; Kaganan, R.

    2008-01-01

    Direct emissions of NOx, volatile organic compounds, and particulate matter (PM) by aircraft contribute to the pollutant levels found in the atmosphere. Aircraft emissions can be injected at the ground level or directly at the high altitude in flight. Conversion of the precursor gases into secondary PM is one of the pathways for the increased atmospheric PM. Atmospheric PM interacts with solar radiation altering atmospheric radiation balance and potentially contributing to global and regional climate changes. Also, direct emissions of air toxics, ozone precursors and PM from aircraft in and around civilian airports and military air bases can worsen local air quality in non-attainment and/or maintenance areas. These emissions need to be quantified. However, the current EPA methods for particle emission measurements from such sources, modified Method 5 and Conditional Test Method 039, are gravimetric-based, and it is anticipated that these methods will not be suitable for current and future generations of aircraft turbine engines, whose particle mass emissions are low. To evaluate measurement approaches for military aircraft emissions, two complementary projects were initiated in 2005. A joint field campaign between these two programs was executed during the first week of October 2005 at the Kentucky Air National Guard (KYANG) base in Louisville, KY. This campaign represented the first in a series of field studies for each program funded by the DoD Strategic Environmental Research and Development Program (SERDP) and provided the basis for cross-comparison of the sampling approaches and measurement techniques employed by the respective program teams. This paper describes the overall programmatic of the multi-year SERDP aircraft emissions research and presents a summary of the results from the joint field campaign.

  14. TEPC reference measurements at aircraft altitudes during a solar storm

    NASA Astrophysics Data System (ADS)

    Beck, P.; Latocha, M.; Rollet, S.; Stehno, G.

    The Sun goes through cycles of high and low activity that repeats approximately every 11 years. The solar activity is correlated to the number of dark spots on the Sun which are sources of sudden, sporadic eruptions, releasing energetic particles into space. This can directly affect the ionosphere and radio communications around the Earth. A spectacular and unusually high sunspot activity occurred during October and November 2003, commonly referred to as the Halloween Storms. The increased radiation exposure at aircraft altitudes during such an event is of major concern to international aviation organizations, airlines, governmental authorities and aircraft crew as well as flight passengers. Here, we report radiation exposure measurements made by ARC Seibersdorf research (ARCS) onboard commercial aircraft using a tissue equivalent proportional counter (TEPC). A unique set of long-term measurements was collected before, during and after the storm at flight altitudes. The results of these investigations give an understanding of the combined effects of magnetic field disturbances and solar particle fluence due to a solar storm, showing a 70% variation in the radiation exposure at typical flight altitudes. Whilst several predictive codes exist the radiation exposure to aircrew during a solar storm is difficult to predict by calculation models. These calculation models are still struggling with the high uncertainty of spectral input data provided by satellites during a solar storm. A reliable dose assessment concept to assess the radiation exposure to aircrew caused by a solar storm using a network of dosimeter instruments on-board several aircraft can be achieved. Such a proposal has been already introduced by experts of the European Radiation Dosimetry Group (EURADOS).

  15. Application of laser velocimetry to aircraft wake-vortex measurements

    NASA Technical Reports Server (NTRS)

    Ciffone, D. L.; Orloff, K. L.

    1977-01-01

    The theory and use of a laser velocimeter that makes simultaneous measurements of vertical and longitudinal velocities while rapidly scanning a flow field laterally are described, and its direct application to trailing wake-vortex research is discussed. Pertinent measurements of aircraft wake-vortex velocity distributions obtained in a wind tunnel and water towing tank are presented. The utility of the velocimeter to quantitatively assess differences in wake velocity distributions due to wake dissipating devices and span loading changes on the wake-generating model is also demonstrated.

  16. First look at the NOAA Aircraft-based Tropospheric Ozone Climatology

    NASA Astrophysics Data System (ADS)

    Leonard, M.; Petropavlovskikh, I. V.; McClure-Begley, A.; Lin, M.; Tarasick, D.; Johnson, B. J.; Oltmans, S. J.

    2015-12-01

    The Global Greenhouse Gas Reference Network's aircraft program has operated since the 1990s as part of the NOAA Global Monitoring Division network to capture spatial and temporal variability in greenhouse tracers (i.e. CO2, CO, N2O, methane, SF6, halo- and hydro-carbons). Since 2005 the suite of airborne measurements also includes ozone, humidity and temperature profiling through the troposphere (up to 8 km). Light commercial aircraft are equipped with modified 2B Technology ozone monitors (Model 205DB), incorporate temperature and humidity probes, and include global positioning system instrumentation. The dataset was analyzed for tropospheric ozone variability at five continental US stations. As site locations within the Tropospheric Aircraft Ozone Measurement Program have flights only once (four times at one site) a month and begun a decade ago, this raises the question of whether this sampling frequency allows the derivation of an accurate vertical climatology of ozone values. We interpret the representativeness of the vertical and seasonal ozone distribution from aircraft measurements using multi-decadal hindcast simulations conducted with the GFDL AM3 chemistry-climate model. When available, climatology derived from co-located ozone-sonde data will be used for comparisons. The results of the comparisons are analyzed to establish altitude ranges in the troposphere where the aircraft climatology would be deemed to be the most representative. Aircraft-based climatologies are tested from two approaches: comparing the aircraft-based climatology to the daily sampled model and to the subset of model data with matching aircraft dates. Whenever the model and aircraft climatologies show significant seasonal differences, further information is gathered from a seasonal Gaussian distribution plot. We will report on the minimum frequency in flights that can provide adequate climatological representation of seasonal and vertical variability in tropospheric ozone.

  17. Solar Radiation Measurements Onboard the Research Aircraft HALO

    NASA Astrophysics Data System (ADS)

    Lohse, I.; Bohn, B.; Werner, F.; Ehrlich, A.; Wendisch, M.

    2014-12-01

    Airborne measurements of the separated upward and downward components of solar spectral actinic flux densities for the determination of photolysis frequencies and of upward nadir spectral radiance were performed with the HALO Solar Radiation (HALO-SR) instrument package onboard the High Altitude and Long Range Research Aircraft (HALO). The instrumentation of HALO-SR is characterized and first measurement data from the Next-generation Aircraft Remote-Sensing for Validation Studies (NARVAL) campaigns in 2013 and 2014 are presented. The measured data are analyzed in the context of the retrieved microphysical and optical properties of clouds which were observed underneath the aircraft. Detailed angular sensitivities of the two optical actinic flux receivers were determined in the laboratory. The effects of deviations from the ideal response are investigated using radiative transfer calculations of atmospheric radiance distributions under various atmospheric conditions and different ground albedos. Corresponding correction factors are derived. Example photolysis frequencies are presented, which were sampled in the free troposphere and lower stratosphere over the Atlantic Ocean during the 2013/14 HALO NARVAL campaigns. Dependencies of photolysis frequencies on cloud cover, flight altitude and wavelength range of the photolysis process are investigated. Calculated actinic flux densities in the presence of clouds benefit from the measured spectral radiances. Retrieved cloud optical thicknesses and effective droplet radii are used as model input for the radiative transfer calculations. By comparison with the concurrent measurements of actinic flux densities the retrieval approach is validated. Acknowledgements: Funding by the Deutsche Forschungsgemeinschaft within the priority program HALO (BO 1580/4-1, WE 1900/21-1) is gratefully acknowledged.

  18. Analysis of Aircraft Clusters to Measure Sector-Independent Airspace Congestion

    NASA Technical Reports Server (NTRS)

    Bilimoria, Karl D.; Lee, Hilda Q.

    2005-01-01

    The Distributed Air/Ground Traffic Management (DAG-TM) concept of operations* permits appropriately equipped aircraft to conduct Free Maneuvering operations. These independent aircraft have the freedom to optimize their trajectories in real time according to user preferences; however, they also take on the responsibility to separate themselves from other aircraft while conforming to any local Traffic Flow Management (TFM) constraints imposed by the air traffic service provider (ATSP). Examples of local-TFM constraints include temporal constraints such as a required time of arrival (RTA), as well as spatial constraints such as regions of convective weather, special use airspace, and congested airspace. Under current operations, congested airspace typically refers to a sector(s) that cannot accept additional aircraft due to controller workload limitations; hence Dynamic Density (a metric that is indicative of controller workload) can be used to quantify airspace congestion. However, for Free Maneuvering operations under DAG-TM, an additional metric is needed to quantify the airspace congestion problem from the perspective of independent aircraft. Such a metric would enable the ATSP to prevent independent aircraft from entering any local areas of congestion in which the flight deck based systems and procedures may not be able to ensure separation. This new metric, called Gaggle Density, offers the ATSP a mode of control to regulate normal operations and to ensure safety and stability during rare-normal or off-normal situations (e.g., system failures). It may be difficult to certify Free Maneuvering systems for unrestricted operations, but it may be easier to certify systems and procedures for specified levels of Gaggle Density that could be monitored by the ATSP, and maintained through relatively minor flow-rate (RTA type) restrictions. Since flight deck based separation assurance is airspace independent, the challenge is to measure congestion independent of sector

  19. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-02-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore we draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14%, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31%) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's aeroelastic wing (53%), as well as sudden changes in wing loading (16%) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95% confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square deviation) of ≈0.4 m s-1 for the horizontal and ≍0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable eddy-covariance flux measurements.

  20. Experimental measurement of structural power flow on an aircraft fuselage

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1991-01-01

    An experimental technique is used to measure structural intensity through an aircraft fuselage with an excitation load applied near one of the wing attachment locations. The fuselage is a relatively large structure, requiring a large number of measurement locations to analyze the whole of the structure. For the measurement of structural intensity, multiple point measurements are necessary at every location of interest. A tradeoff is therefore required between the number of measurement transducers, the mounting of these transducers, and the accuracy of the measurements. Using four transducers mounted on a bakelite platform, structural intensity vectors are measured at locations distributed throughout the fuselage. To minimize the errors associated with using the four transducer technique, the measurement locations are selected to be away from bulkheads and stiffeners. Furthermore, to eliminate phase errors between the four transducer measurements, two sets of data are collected for each position, with the orientation of the platform with the four transducers rotated by 180 degrees and an average taken between the two sets of data. The results of these measurements together with a discussion of the suitability of the approach for measuring structural intensity on a real structure are presented.

  1. A Comprehensive Program for Measurement of Military Aircraft Emissions

    SciTech Connect

    Cheng, Mengdawn

    2009-11-01

    Emissions of gases and particulate matter by military aircraft were characterized inplume by 'extractive' and 'optical remote-sensing (ORS)' technologies. Non-volatile particle size distribution, number and mass concentrations were measured with good precision and reproducibly. Time-integrated particulate filter samples were collected and analyzed for smoke number, elemental composition, carbon contents, and sulfate. Observed at EEP the geometric mean diameter (as measured by the mobility diameter) generally increased as the engine power setting increased, which is consistent with downstream observations. The modal diameters at the downstream locations are larger than that at EEP at the same engine power level. The results indicate that engine particles were processed by condensation, for example, leading to particle growth in-plume. Elemental analysis indicated little metals were present in the exhaust, while most of the exhaust materials in the particulate phase were carbon and sulfate (in the JP-8 fuel). CO, CO{sub 2}, NO, NO{sub 2}, SO{sub 2}, HCHO, ethylene, acetylene, propylene, and alkanes were measured. The last five species were most noticeable under engine idle condition. The levels of hydrocarbons emitted at high engine power level were generally below the detection limits. ORS techniques yielded real-time gaseous measurement, but the same techniques could not be extended directly to ultrafine particles found in all engine exhausts. The results validated sampling methodology and measurement techniques used for non-volatile particulate aircraft emissions, which also highlighted the needs for further research on sampling and measurement for volatile particulate matter and semi-volatile species in the engine exhaust especially at the low engine power setting.

  2. Benefits and limitations of composites in carrier-based aircraft

    NASA Technical Reports Server (NTRS)

    Mcerlean, Donald P.

    1992-01-01

    There are many unique aspects of Navy air missions that lead to the differentiation between the design and performance of ship and shore-based aircraft. The major aspects are discussed from which essentially all Navy aircraft design requirements derive. (1) Navy aircraft operate from carriers at sea imposes a broad spectrum of physical conditions, constraints, and requirements ranging from the harsh sea environment, the space limitations of a carrier, takeoff and landing requirements as well as for endurance at long distances from the carrier. (2) Because the carrier and its airwing are intended to be capable of responding to a broad range of contingencies, mission flexibility is essential (maximum weapon carriage, rapid reconfiguration, multiple mission capability). (3) The embarked aircraft provides the long range defense of the battle group against air, surface and subsurface launched antiship missiles. (4) The carrier and its aircraft must operate independently and outside of normal supply lines. Taking into account these aspects, the use of composite materials in the design and performance of naval aircraft is outlined, also listing advantages and disadvantages.

  3. Comparative Optical Measurements of Airspeed and Aerosols on a DC-8 Aircraft

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney; McGann, Rick; Wagener, Thomas; Abbiss, John; Smart, Anthony

    1997-01-01

    NASA Dryden supported a cooperative flight test program on the NASA DC-8 aircraft in November 1993. This program evaluated optical airspeed and aerosol measurement techniques. Three brassboard optical systems were tested. Two were laser Doppler systems designed to measure free-stream-referenced airspeed. The third system was designed to characterize the natural aerosol statistics and airspeed. These systems relied on optical backscatter from natural aerosols for operation. The DC-8 aircraft carried instrumentation that provided real-time flight situation information and reference data on the aerosol environment. This test is believed to be the first to include multiple optical airspeed systems on the same carrier aircraft, so performance could be directly compared. During 23 hr of flight, a broad range of atmospheric conditions was encountered, including aerosol-rich layers, visible clouds, and unusually clean (aerosol-poor) regions. Substantial amounts of data were obtained. Important insights regarding the use of laser-based systems of this type in an aircraft environment were gained. This paper describes the sensors used and flight operations conducted to support the experiments. The paper also briefly describes the general results of the experiments.

  4. Analysis of aircraft microwave measurements of the ocean surface

    NASA Technical Reports Server (NTRS)

    Willand, J. H.; Fowler, M. G.; Reifenstein, E. C., III; Chang, D. T.

    1973-01-01

    A data system was developed to process, from calibrated brightness temperature to computation of estimated parameters, the microwave measurements obtained by the NASA CV-990 aircraft during the 1972 Meteorological Expedition. A primary objective of the study was the implementation of an integrated software system at the computing facility of NASA/GSFC, and its application to the 1972 data. A single test case involving measurements away from and over a heavy rain cell was chosen to examine the effect of clouds upon the ability to infer ocean surface parameters. The results indicate substantial agreement with those of the theoretical study; namely, that the values obtained for the surface properties are consistent with available ground-truth information, and are reproducible except within the heaviest portions of the rain cell, at which nonlinear (or saturation) effects become apparent. Finally, it is seen that uncorrected instrumental effects introduce systematic errors which may limit the accuracy of the method.

  5. Inferring Small Scale Dynamics from Aircraft Measurements of Tracers

    NASA Technical Reports Server (NTRS)

    Sparling, L. C.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The millions of ER-2 and DC-8 aircraft measurements of long-lived tracers in the Upper Troposphere/Lower Stratosphere (UT/LS) hold enormous potential as a source of statistical information about subgrid scale dynamics. Extracting this information however can be extremely difficult because the measurements are made along a 1-D transect through fields that are highly anisotropic in all three dimensions. Some of the challenges and limitations posed by both the instrumentation and platform are illustrated within the context of the problem of using the data to obtain an estimate of the dissipation scale. This presentation will also include some tutorial remarks about the conditional and two-point statistics used in the analysis.

  6. Aircraft measurements of microwave emission from Arctic Sea ice

    USGS Publications Warehouse

    Wilheit, T.; Nordberg, W.; Blinn, J.; Campbell, W.; Edgerton, A.

    1971-01-01

    Measurements of the microwave emission from Arctic Sea ice were made with aircraft at 8 wavelengths ranging from 0.510 to 2.81 cm. The expected contrast in emissivities between ice and water was observed at all wavelengths. Distributions of sea ice and open water were mapped from altitudes up to 11 km in the presence of dense cloud cover. Different forms of ice also exhibited strong contrasts in emissivity. Emissivity differences of up to 0.2 were observed between two types of ice at the 0.811-cm wavelength. The higher emissivity ice type is tentatively identified as having been formed more recently than the lower emissivity ice. ?? 1971.

  7. Surface Roughness Measurement on a Wing Aircraft by Speckle Correlation

    PubMed Central

    Salazar, Félix; Barrientos, Alberto

    2013-01-01

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given. PMID:24013488

  8. Surface roughness measurement on a wing aircraft by speckle correlation.

    PubMed

    Salazar, Félix; Barrientos, Alberto

    2013-09-05

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  9. Evaluation of Space-Based Constraints on Global Nitrogen Oxide Emissions with Regional Aircraft Measurements over and Downwind of Eastern North America

    NASA Technical Reports Server (NTRS)

    Martin, Randall V.; Sioris, Christopher E.; Chance, Kelly; Ryerson, Thomas B.; Flocke, Frank M.; Bertram, Timothy H.; Wooldridge, Paul J.; Cohen, Ronald C.; Neuman, J. Andy; Swanson, Aaron

    2006-01-01

    We retrieve tropospheric nitrogen dioxide (NO 2) columns for May 2004 to April 2005 from the SCIAMACHY satellite instrument to derive top-down emissions of nitrogen oxides (NO(x) = NO + NO2) via inverse modeling with a global chemical transport model (GEOS-Chem). Simulated NO 2 vertical profiles used in the retrieval are evaluated with airborne measurements over and downwind of North America (ICARTT); a northern midlatitude lightning source of 1.6 Tg N/yr minimizes bias in the retrieval. Retrieved NO2 columns are validated (r2 = 0.60, slope = 0.82) with coincident airborne in situ measurements. The top-down emissions are combined with a priori information from a bottom-up emission inventory with error weighting to achieve an improved a posteriori estimate of the global distribution of surface NOx emissions. Our a posteriori NOx emission inventory for land surface NOx emissions (46.1 Tg N/yr) is 22% larger than the GEIA-based a priori bottom-up inventory for 1998, a difference that reflects rising anthropogenic emissions, especially from East Asia A posteriori NOx emissions for East Asia (9.8 Tg N/yr) exceed those from other continents. The a posteriori inventory improves the GEOS-Chem simulation of NOx, peroxyacetylnitrate, and nitric acid with respect to airborne in situ measurements over and downwind of New York City. The a posteriori is 7% larger than the EDGAR 3.2FT2000 global inventory, 3% larger than the NEI99 inventory for the United States, and 68% larger than a regional inventory for 2000 for eastern Asia. SCIAMACHY NO2 columns over the North Atlantic show a weak plume from lightning NO(x).

  10. Wide field of view laser beacon system for three dimensional aircraft range measurements

    NASA Technical Reports Server (NTRS)

    Wong, E. Y.

    1982-01-01

    A system that measures accurately the distance from an aircraft to a helicoper for rotor noise flight testing was developed. The system measures the range and angles between two aircraft using laser optics. This system can be applied in collision avoidance, robotics and other measurement critical tasks.

  11. Measurements of nitrous acid in commercial aircraft exhaust at the Alternative Aviation Fuel Experiment.

    PubMed

    Lee, Ben H; Santoni, Gregory W; Wood, Ezra C; Herndon, Scott C; Miake-Lye, Richard C; Zahniser, Mark S; Wofsy, Steven C; Munger, J William

    2011-09-15

    The Alternative Aviation Fuel Experiment (AAFEX), conducted in January of 2009 in Palmdale, California, quantified aerosol and gaseous emissions from a DC-8 aircraft equipped with CFM56-2C1 engines using both traditional and synthetic fuels. This study examines the emissions of nitrous acid (HONO) and nitrogen oxides (NO(x) = NO + NO(2)) measured 145 m behind the grounded aircraft. The fuel-based emission index (EI) for HONO increases approximately 6-fold from idle to takeoff conditions but plateaus between 65 and 100% of maximum rated engine thrust, while the EI for NO(x) increases continuously. At high engine power, NO(x) EI is greater when combusting traditional (JP-8) rather than Fischer-Tropsch fuels, while HONO exhibits the opposite trend. Additionally, hydrogen peroxide (H(2)O(2)) was identified in exhaust plumes emitted only during engine idle. Chemical reactions responsible for emissions and comparison to previous measurement studies are discussed.

  12. A Low LET Radiation Spectrometer for Measuring Particle Doses in Space and Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Brucker, G. J.; Dachev, T. P.; Day, John H. (Technical Monitor)

    2002-01-01

    This paper presents experimental data that demonstrates the feasibility of fabricating a miniature nuclear particle dosimeter for monitoring doses in aircraft and satellites. The basic instrument is a Low Linear-Energy-Transfer (LET) Radiation Spectrometer (LoLRS) that is designed to measure the energy deposited by particles with low LET values. The heart of the instrument is a Silicon-Lithium Drifted Diode (SLDD). Test results show that the LoLRS can be used to monitor the radiation threat to personnel in flights of space- and aircraft and also to generate a comprehensive data base from aviation and satellite measurements that can contribute to the formulation of more accurate environmental radiation models for dose predictions with reduced uncertainty factors.

  13. Evaluation of Contrail Reduction Strategies Based on Aircraft Flight Distances

    NASA Technical Reports Server (NTRS)

    Chen, Neil Y.; Sridhar, Banavar; Li, Jinhua; Ng, Hok Kwan

    2012-01-01

    This paper evaluates a set of contrail reduction strategies based on the flight range of aircraft as contrail reduction strategies have different impacts on aircraft depending on how they plan to fly. In general, aircraft with longer flight distances cruise at the altitudes where contrails are more likely to form. The concept of the contrail frequency index is used to quantify contrail impacts. The strategy for reducing the persistent contrail formation is to minimize the contrail frequency index by altering the aircraft's cruising altitude. A user-defined factor is used to trade off between contrail reduction and extra CO2 emissions. A higher value of tradeoff factor results in more contrail reduction and extra CO2 emissions. Results show that contrail reduction strategies using various tradeo factors behave differently from short-range flights to long-range ights. Analysis shows that short-distance flights (less than 500 miles) are the most frequent flights but contribute least to contrail reduction. Therefore these aircraft have the lowest priority when applying contrail reduction strategies. Medium-distance flights (500 to 1000 miles) have a higher priority if the goal is to achieve maximum contrail reduction in total; long-distance flights (1000 to 1500 miles) have a higher priority if the goal is to achieve maximum contrail reduction per flight. The characteristics of transcontinental flights (greater than 1500 miles) vary with different weather days so the priority of applying contrail reduction strategies to the group needs to be evaluated based on the locations of the contrail areas during any given day. For the days tested, medium-distance ights contribute up to 42.6% of the reduction among the groups during a day. The contrail frequency index per 1,000 miles for medium-distance, long-distance, and transcontinental flights can be reduced by an average of 75%. The results provide a starting point for developing operational policies to reduce the impact of

  14. Requirements for facilities and measurement techniques to support CFD development for hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Sellers, William L., III; Dwoyer, Douglas L.

    1992-01-01

    The design of a hypersonic aircraft poses unique challenges to the engineering community. Problems with duplicating flight conditions in ground based facilities have made performance predictions risky. Computational fluid dynamics (CFD) has been proposed as an additional means of providing design data. At the present time, CFD codes are being validated based on sparse experimental data and then used to predict performance at flight conditions with generally unknown levels of uncertainty. This paper will discuss the facility and measurement techniques that are required to support CFD development for the design of hypersonic aircraft. Illustrations are given of recent success in combining experimental and direct numerical simulation in CFD model development and validation for hypersonic perfect gas flows.

  15. Information fusion based optimal control for large civil aircraft system.

    PubMed

    Zhen, Ziyang; Jiang, Ju; Wang, Xinhua; Gao, Chen

    2015-03-01

    Wind disturbance has a great influence on landing security of Large Civil Aircraft. Through simulation research and engineering experience, it can be found that PID control is not good enough to solve the problem of restraining the wind disturbance. This paper focuses on anti-wind attitude control for Large Civil Aircraft in landing phase. In order to improve the riding comfort and the flight security, an information fusion based optimal control strategy is presented to restrain the wind in landing phase for maintaining attitudes and airspeed. Data of Boeing707 is used to establish a nonlinear mode with total variables of Large Civil Aircraft, and then two linear models are obtained which are divided into longitudinal and lateral equations. Based on engineering experience, the longitudinal channel adopts PID control and C inner control to keep longitudinal attitude constant, and applies autothrottle system for keeping airspeed constant, while an information fusion based optimal regulator in the lateral control channel is designed to achieve lateral attitude holding. According to information fusion estimation, by fusing hard constraint information of system dynamic equations and the soft constraint information of performance index function, optimal estimation of the control sequence is derived. Based on this, an information fusion state regulator is deduced for discrete time linear system with disturbance. The simulation results of nonlinear model of aircraft indicate that the information fusion optimal control is better than traditional PID control, LQR control and LQR control with integral action, in anti-wind disturbance performance in the landing phase.

  16. Aircraft measurements over Fennoscandia during the MAMM project - highlights from 2012-2014

    NASA Astrophysics Data System (ADS)

    Allen, Grant

    2015-04-01

    This paper will present highlights and conclusions from a 3-year campaign of summer airborne measurements across the Fennoscandian region and over the Barents Sea and Svalbard during the Methane in the Arctic Measurements and Modelling (MAMM) campaign. Beginning in July 2012, the UK Facility for Airborne Atmospheric Measurement (FAAM) Bae-146 Atmospheric Research Aircraft has conducted more than 150 hours of sampling over this Arctic domain in a series of tailored process-driven case studies in the period July to September in each year between 2012 and 2014. High precision, continuous measurements of methane concentration and its isotopologues were collected on the FAAM aircraft along with measurements of a wide range of other gases (such as CO2, N2O, O3, CO, HCOOH), aerosol, and thermodynamic parameters. Together, such measurements provide a dataset from which to assess physico-chemical airmass history and specific local and regional emission processes. The FAAM platform complemented a longer term ground-based measurement deployment to collect data for measurement-led case studies, and regional and global model evaluation. In this study we will present highlights from case studies of regionally-averaged snapshots of Arctic wetland methane and formic acid net surface flux and we will present conclusions from airborne methane measurements over potential gas seepage areas on the continental shelf off the coast of Svalbard. We will also present the first airborne remote sensing measurements of methane over the region from the FAAM aircraft and we will present a summer climatology of greenhouse measurements across the MAMM campaign. We will conclude by discussing the next steps in completing the Arctic methane picture and what this might mean for the global methane conundrum.

  17. The IAGOS Information System: From the aircraft measurements to the users.

    NASA Astrophysics Data System (ADS)

    Boulanger, Damien; Thouret, Valérie; Cammas, Jean-Pierre; Petzold, Andreas; Volz-Thomas, Andreas; Gerbig, Christoph; Brenninkmeijer, Carl A. M.

    2013-04-01

    IAGOS (In-service Aircraft for a Global Observing System, http://www.iagos.org) aims at the provision of long-term, frequent, regular, accurate, and spatially resolved in-situ observations of atmospheric chemical composition throughout the troposphere and in the UTLS. It builds on almost 20 years of scientific and technological expertise gained in the research projects MOZAIC (Measurement of Ozone and Water Vapour on Airbus In-service Aircraft) and CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container). The European consortium includes research centres, universities, national weather services, airline operators and aviation industry. IAGOS consists of two complementary building blocks proving a unique global observation system: IAGOS-CORE deploys newly developed instrumentation for regular in-situ measurements of atmospheric chemical species both reactive and greenhouse gases (O3, CO, NOx, NOy, H2O, CO2, CH4), aerosols and cloud particles. In IAGOS-CARIBIC a cargo container is deployed monthly as a flying laboratory aboard one aircraft. Involved airlines ensure global operation of the network. Today, 5 aircraft are flying with the MOZAIC (3) or IAGOS-CORE (2) instrumentation namely 3 aircraft from Lufthansa, 1 from Air Namibia, and 1 from China Airlines Taiwan. A main improvement and new aspect of the IAGOS-CORE instrumentation compared to MOZAIC is to deliver the raw data in near real time (i.e. as soon as the aircraft lands data are transmitted). After a first and quick validation of the O3 and CO measurements, preliminary data are made available in the central database for both the MACC project (Monitoring Atmospheric Composition and Climate) and scientific research groups. In addition to recorded measurements, the database also contains added-value products such as meteorological information (tropopause height, air mass backtrajectories) and lagrangian model outputs (FLEXPART). Data access is handled by open

  18. Knowledge-based processing for aircraft flight control

    NASA Technical Reports Server (NTRS)

    Painter, John H.

    1991-01-01

    The purpose is to develop algorithms and architectures for embedding artificial intelligence in aircraft guidance and control systems. With the approach adopted, AI-computing is used to create an outer guidance loop for driving the usual aircraft autopilot. That is, a symbolic processor monitors the operation and performance of the aircraft. Then, based on rules and other stored knowledge, commands are automatically formulated for driving the autopilot so as to accomplish desired flight operations. The focus is on developing a software system which can respond to linguistic instructions, input in a standard format, so as to formulate a sequence of simple commands to the autopilot. The instructions might be a fairly complex flight clearance, input either manually or by data-link. Emphasis is on a software system which responds much like a pilot would, employing not only precise computations, but, also, knowledge which is less precise, but more like common-sense. The approach is based on prior work to develop a generic 'shell' architecture for an AI-processor, which may be tailored to many applications by describing the application in appropriate processor data bases (libraries). Such descriptions include numerical models of the aircraft and flight control system, as well as symbolic (linguistic) descriptions of flight operations, rules, and tactics.

  19. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    NASA Astrophysics Data System (ADS)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

  20. Aerosol Formation In The Free Troposphere: Aircraft and Laboratory Measurements of Ionic and Gaseous Aerosol Precursors

    NASA Astrophysics Data System (ADS)

    Arnold, F.

    Aerosol formation seems to be very efficient in the upper troposphere (UT) as in- dicated by the frequent presence of numerous very small and therefore very young aerosol particles. Aersosol formation proceeds via nucleation of supersaturated low volatility trace gases (LVG) involving either a homogeneous (HONU) or an ion- induced (INU) mechanism. LVG experience rapid removal by condenstation on prefer- ably pre-existing aerosol particles and therefore LVG must be formed locally in the UT by photochemical conversion of precursor gases. A prominent example is gaseous sulfuric acid which is formed from SO2. This SO2 originates at least in the northern hemisphere mostly from fossil fuel combustion at ground-level and to some part origi- nates also from jet aircraft cruising in the UT. Other conceivable LVG's are low volatil- ity organic compounds. After formation by nucleation new particles may experience condensational growth involving LVG. Alternatively new particles may experience scavenging by attachment to pre-existing larger particles. The LVG-concentration has a strong influence on the growth-rate of new particles and thereby on the possibil- ity for growth to the size of a cloud condensation nucleus. Unfortunately present knowledge on free tropospheric LVG is rather poor. Here will be reported free tropo- spheric aircraft-based measurements of ionic and gaseous aerosol-precursors. These include both measurements in the "background" FT as well as measurements in ex- haust plumes of jet aircraft cruising in the UT. Furthermore accompanying new labo- ratory investigations of INU and measurements behind aircraft jet engines at ground- level will also be adressed.

  1. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    SciTech Connect

    Moore, D.G.; Jones, C.R.; Mihelic, J.E.; Barnes, J.D.

    1998-08-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft`s right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in-flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft`s right main wheel fairing. Inspection results and techniques developed to verify the aircraft`s structural integrity are discussed.

  2. In-flight and simulated aircraft fuel temperature measurements

    NASA Technical Reports Server (NTRS)

    Svehla, Roger A.

    1990-01-01

    Fuel tank measurements from ten flights of an L1011 commercial aircraft are reported for the first time. The flights were conducted from 1981 to 1983. A thermocouple rake was installed in an inboard wing tank and another in an outboard tank. During the test periods of either 2 or 5 hr, at altitudes of 10,700 m (35,000 ft) or higher, either the inboard or the outboard tank remained full. Fuel temperature profiles generally developed in the expected manner. The bulk fuel was mixed by natural convection to a nearly uniform temperature, especially in the outboard tank, and a gradient existed at the bottom conduction zone. The data indicated that when full, the upper surface of the inboard tank was wetted and the outboard tank was unwetted. Companion NASA Lewis Research Center tests were conducted in a 0.20 cubic meter (52 gal) tank simulator of the outboard tank, chilled on the top and bottom, and insulated on the sides. Even though the simulator tank had no internal components corresponding to the wing tank, temperatures agreed with the flight measurements for wetted upper surface conditions, but not for unwetted conditions. It was concluded that if boundary conditions are carefully controlled, simulators are a useful way of evaluating actual flight temperatures.

  3. Perspectives on African Ozone from Sondes, Dobson and Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Thompson, A. M.; Witte, J. C.; Chatfield, R. B.; Diab, R. D.; Thouret, V.; Sauvage, B.

    2004-01-01

    We have been studying variability in ozone over Africa using data from ozonesondes (vertical profiles from surface to stratosphere), aircraft (the MOZAIC dataset with cruise altitude and landing/takeoff profiles) and the ground (Dobson spectrophotometer total ozone column measurement). The following may give context for ozone investigations during AMMA: 1. Total ozone measurements since 1989 show considerable variability in mean value among the African stations in Algeria, Kenya, Egypt, South Africa, as well as in seasonal cycles and year-to-year. Trends are not evident. 2. The impacts of convection, stratospheric injection, biomass burning and lightning appear in ozone sounding profile data. Time-series analysis and case studies point to periodic influences of long-range interactions with the Atlantic ("ozone paradox," wave-one") and Indian Oceans. 3. Tropospheric ozone variations, observed in tropospheric profiles and integrated column amount, follow general seasonal patterns but short- term variability is so strong that simple averages are inadequate for describing "climatology" and statistical classification approaches may be required.

  4. NASA Boeing 737 Aircraft Test Results from 1996 Joint Winter Runway Friction Measurement Program

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1996-01-01

    A description of the joint test program objectives and scope is given together with the performance capability of the NASA Langley B-737 instrumented aircraft. The B-737 test run matrix conducted during the first 8 months of this 5-year program is discussed with a description of the different runway conditions evaluated. Some preliminary test results are discussed concerning the Electronic Recording Decelerometer (ERD) readings and a comparison of B-737 aircraft braking performance for different winter runway conditions. Detailed aircraft parameter time history records, analysis of ground vehicle friction measurements and harmonization with aircraft braking performance, assessment of induced aircraft contaminant drag, and evaluation of the effects of other factors on aircraft/ground vehicle friction performance will be documented in a NASA Technical Report which is being prepared for publication next year.

  5. Measurements of Aged Aircraft Exhaust in the ACCENT Mission

    NASA Technical Reports Server (NTRS)

    Friedl, R.; Ross, A.

    2000-01-01

    The Atmospheric Chemistry of Combustion Emissions Near the Tropopause (ACCENT) mission is a multi-agency sponsored effort to evaluate the roles of aircraft and rocket exhaust in perturbing ozone chemistry and modifying aerosols and clouds.

  6. Aircraft Wake Vortex Measurements at Denver International Airport

    NASA Technical Reports Server (NTRS)

    Dougherty, Robert P.; Wang, Frank Y.; Booth, Earl R.; Watts, Michael E.; Fenichel, Neil; D'Errico, Robert E.

    2004-01-01

    Airport capacity is constrained, in part, by spacing requirements associated with the wake vortex hazard. NASA's Wake Vortex Avoidance Project has a goal to establish the feasibility of reducing this spacing while maintaining safety. Passive acoustic phased array sensors, if shown to have operational potential, may aid in this effort by detecting and tracking the vortices. During August/September 2003, NASA and the USDOT sponsored a wake acoustics test at the Denver International Airport. The central instrument of the test was a large microphone phased array. This paper describes the test in general terms and gives an overview of the array hardware. It outlines one of the analysis techniques that is being applied to the data and gives sample results. The technique is able to clearly resolve the wake vortices of landing aircraft and measure their separation, height, and sinking rate. These observations permit an indirect estimate of the vortex circulation. The array also provides visualization of the vortex evolution, including the Crow instability.

  7. An experimental measurement of galactic cosmic radiation dose in conventional aircraft between San Francisco and London compared to theoretical values for conventional and supersonic aircraft

    NASA Technical Reports Server (NTRS)

    Wallace, R.; Boyer, M. F.

    1972-01-01

    These direct measurements are in fair agreement with computations made using a program which considers both basic cosmic ray atmospheric physics and the focusing effect of the earth's magnetic field. These measurements also agree with those made at supersonic jet aircraft altitudes in Rb-57 aircraft. It is concluded that experiments and theory show that the doses received at conventional jet aircraft altitudes are slightly higher than those encountered in supersonic flights at much higher altitudes.

  8. Development and Flight Testing of a Neural Network Based Flight Control System on the NF-15B Aircraft

    NASA Technical Reports Server (NTRS)

    Bomben, Craig R.; Smolka, James W.; Bosworth, John T.; Silliams-Hayes, Peggy S.; Burken, John J.; Larson, Richard R.; Buschbacher, Mark J.; Maliska, Heather A.

    2006-01-01

    The Intelligent Flight Control System (IFCS) project at the NASA Dryden Flight Research Center, Edwards AFB, CA, has been investigating the use of neural network based adaptive control on a unique NF-15B test aircraft. The IFCS neural network is a software processor that stores measured aircraft response information to dynamically alter flight control gains. In 2006, the neural network was engaged and allowed to learn in real time to dynamically alter the aircraft handling qualities characteristics in the presence of actual aerodynamic failure conditions injected into the aircraft through the flight control system. The use of neural network and similar adaptive technologies in the design of highly fault and damage tolerant flight control systems shows promise in making future aircraft far more survivable than current technology allows. This paper will present the results of the IFCS flight test program conducted at the NASA Dryden Flight Research Center in 2006, with emphasis on challenges encountered and lessons learned.

  9. Design of an infrared camera based aircraft detection system for laser guide star installations

    SciTech Connect

    Friedman, H.; Macintosh, B.

    1996-03-05

    There have been incidents in which the irradiance resulting from laser guide stars have temporarily blinded pilots or passengers of aircraft. An aircraft detection system based on passive near infrared cameras (instead of active radar) is described in this report.

  10. Deflection-Based Structural Loads Estimation From the Active Aeroelastic Wing F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lizotte, Andrew M.; Lokos, William A.

    2005-01-01

    Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. This technique was examined using a reliable strain and structural deformation measurement system. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.

  11. Cosmic radiation measurements on-board aircraft with the variance method.

    PubMed

    Kyllönen, J E; Lindborg, L; Samuelson, G

    2001-01-01

    The microdosimetric variance-covariance method has been used for cosmic radiation measurements on-board aircraft. Two independent methods of data analysis are presented; the first based on a high energy neutron calibration and the second on identification of single high LET events in the measured multiple event spectrum. Reduced dose levels at high geomagnetic latitudes are observed on one flight in a period of enhanced solar activity as indicated by a reduced ground-level neutron fluence rate. It is shown that with a reduced 137Cs-calibration factor, a Geiger-Mueller tube can be used as a low LET monitor, and that the wall thickness of a tissue-equivalent proportional counter is not crucial for flight measurements. No covariance is observed on any flight indicating it is sufficient to base dose determinations on variance measurements with only one detector. The uncertainties involved are also discussed in some detail.

  12. Aircraft measurements of O3, HNO3, and N2O in the winter Arctic lower stratosphere during the Stratosphere-Troposphere Experiment by Aircraft Measurements (STREAM) 1

    NASA Astrophysics Data System (ADS)

    Bregman, A.; van Velthoven, P. F. J.; Wienhold, F. G.; Fischer, H.; Zenker, T.; Waibel, A.; Frenzel, A.; Arnold, F.; Harris, G. W.; Bolder, M. J. A.; Lelieveld, J.

    1995-06-01

    Simultaneous in situ measurements of O3, HNO3, and N2O were performed in the Arctic (68°-74°N) lower stratosphere during February 1993 on board a Cessna Citation aircraft up to 12.5 km altitude, during the first Stratosphere-Troposphere Experiment by Aircraft Measurements (STREAM) campaign. Strong variations in the concentrations, distributions, and ratios of these trace gases were found from the maximum altitude down to the tropopause. Close to the tropopause, vortex air was present with relatively low N2O concentrations. The observed N2O-HNO3 relation agrees with earlier measurements of total nitrogen and N2O inside the vortex, suggesting subsidence of vortex air across the bottom of the vortex. This air also contained low O3 concentrations relative to N2O, indicating enhanced O3 loss by chemical reactions involving stratospheric particles. Based on trajectory calculations and assuming a potential temperature cooling rate of 0.6 K d-1, we estimate an O3 loss of 4-7 ppbv d-1 (0.9-1.2% d-1), in the Arctic lower stratosphere for the period January-February 1993. Air parcels originating from middle latitudes, containing relatively low O3 and N2O concentrations, may have originated from the vortex earlier in the winter. In addition, the results also show high HNO3 concentrations relative to O3 and N2O. Air parcels originating from high latitudes may have been enriched in HNO3 by sedimentation and evaporation of nitric acid containing particles, which would explain the relatively high HNO3 concentrations and HNO3/O3 ratios measured. Heterogeneous chemistry on sulfuric acid particles, probably enhanced in concentration by gravitational settling of the Pinatubo aerosol, is the most plausible explanation for the observed high HNO3 concentrations relative to N2O in air parcels originating from midlatitudes.

  13. A comparison of vertical velocity in cirrus obtained from aircraft and lidar divergence measurements during FIRE. [First ISCCP Regional Experiment

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Heymsfield, A. J.; Lenschow, D. H.

    1990-01-01

    Techniques are presented to obtain vertical velocity in cirrus clouds from in situ aircraft lateral wind measurements and from ground-based remote Doppler lidar measurements. The approach used is to calculate w from the integral of the divergence of the horizontal velocity around a closed path. Divergence measurements from both aircraft and Doppler lidar are discussed. The principal errors in the calculation of w from aircraft lateral wind measurements are bias in the lateral wind, ground speed errors, and error due to vertical shear of the horizontal wind. For Doppler lidar measurements the principal errors are in the estimate of mean terminal velocity and the zeroth order coefficients of the Fourier series that is fitted to the data. The technique is applied to a cirrus cloud investigated during the FIRE (First International Satellite Cloud Climatology Regional Experiment) Cirrus Intensive Field Observation Program. The results indicate that the error in w is about + or - 14 cm/s from the aircraft technique; this can be reduced to about + or - 2 to 3 cm/s with technical improvements in both ground speed and lateral velocity measurements. The error in w from Doppler lidar measurements, which is about + or - 8 cm/s, can be reduced to about + or - 5 cm/s by improvements in the Doppler velocity measurements with technology that is currently available.

  14. Aircraft- and tower-based fluxes of carbon dioxide, latent, and sensible heat

    NASA Technical Reports Server (NTRS)

    Desjardins, R. L.; Hart, R. L.; Macpherson, J. I.; Schuepp, P. H.; Verma, S. B.

    1992-01-01

    Fluxes of carbon dioxide, water vapor, and sensible heat obtained over a grassland ecosystem, during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), using an aircraft- and two tower-based systems are compared for several days in 1987 and in 1989. The tower-based cospectral estimates of CO2, sensible heat, water vapor, and momentum, expressed as a function of wavenumber K times sampling height z, are relatively similar to the aircraft-based estimates for K x z greater than 0.1. A measurable contribution to the fluxes is observed by tower-based systems at K x z less than 0.01 but not by the aircraft-based system operating at an altitude of approximately 100 m over a 15 x 15 km area. Using all available simultaneous aircraft and tower data, flux estimates by both systems were shown to be highly correlated. As expected from the spatial variations of the greenness index, surface extrapolation of airborne flux estimates tended to lie between those of the two tower sites. The average fluxes obtained, on July 11, 1987, and August 4, 1989, by flying a grid pattern over the FIFE site agreed with the two tower data sets for CO2, but sensible and latent heat were smaller than those obtained by the tower-based systems. However, in general, except for a small underestimation due to the long wavelength contributions and due to flux divergence with height, the differences between the aircraft- and tower-based surface estimates of fluxes appear to be mainly attributable to differences in footprint, that is, differences in the area contributing to the surface flux estimates.

  15. Aircraft- and tower-based fluxes of carbon dioxide, latent, and sensible heat

    SciTech Connect

    Desjardins, R.L.; Hart, R.L.; Macpherson, J.I.; Schuepp, P.H.; Verma, S.B. Argonne National Lab., IL National Research Council of Canada, Flight Research Lab., Ottawa McGill Univ., Sainte-Anne-de-Bellevue Nebraska Univ., Lincoln )

    1992-11-01

    Fluxes of carbon dioxide, water vapor, and sensible heat obtained over a grassland ecosystem, during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), using an aircraft- and two tower-based systems are compared for several days in 1987 and in 1989. The tower-based cospectral estimates of CO2, sensible heat, water vapor, and momentum, expressed as a function of wavenumber K times sampling height z, are relatively similar to the aircraft-based estimates for K x z greater than 0.1. A measurable contribution to the fluxes is observed by tower-based systems at K x z less than 0.01 but not by the aircraft-based system operating at an altitude of approximately 100 m over a 15 x 15 km area. Using all available simultaneous aircraft and tower data, flux estimates by both systems were shown to be highly correlated. As expected from the spatial variations of the greenness index, surface extrapolation of airborne flux estimates tended to lie between those of the two tower sites. The average fluxes obtained, on July 11, 1987, and August 4, 1989, by flying a grid pattern over the FIFE site agreed with the two tower data sets for CO2, but sensible and latent heat were smaller than those obtained by the tower-based systems. However, in general, except for a small underestimation due to the long wavelength contributions and due to flux divergence with height, the differences between the aircraft- and tower-based surface estimates of fluxes appear to be mainly attributable to differences in footprint, that is, differences in the area contributing to the surface flux estimates. 21 refs.

  16. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

    NASA Astrophysics Data System (ADS)

    Hermann, Markus; Weigelt, Andreas; Assmann, Denise; Pfeifer, Sascha; Muller, Thomas; Conrath, Thomas; Voigtlander, Jens; Heintzenberg, Jost; Wiedensohler, Alfred; Martinsson, Bengt G.; Deshler, Terry; Brenninkmeijer, Carl A. M.; Zahn, Andreas

    2016-05-01

    The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new optical particle size spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region on board a passenger aircraft (IAGOS-CARIBIC observatory: In-service Aircraft for a Global Observing System - Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container). A modified KS93 particle sensor from RION Co., Ltd., together with a new airflow system and a dedicated data acquisition system, is the key component of the CARIBIC OPSS. The instrument records individual particle pulse signal curves in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006) together with a time stamp and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instrument's measurement performance shows no pressure dependency and no particle coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of 2 in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

  17. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

    NASA Astrophysics Data System (ADS)

    Hermann, M.; Weigelt, A.; Assmann, D.; Pfeifer, S.; Müller, T.; Conrath, T.; Voigtländer, J.; Heintzenberg, J.; Wiedensohler, A.; Martinsson, B. G.; Deshler, T.; Brenninkmeijer, C. A. M.; Zahn, A.

    2015-11-01

    The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new Optical Particle Size Spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region onboard a passenger aircraft (IAGOS-CARIBIC observatory (In-service Aircraft for a Global Observing System - Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container)). A modified "KS93 particle sensor" from RION Co., Ltd. together with a new airflow system and a dedicated data acquisition system are the key components of the CARIBIC OPSS. The instrument records individual particle pulses in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006 for an upper tropospheric (UT) aerosol particle) and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instruments measurement performance shows no pressure dependency and no coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of two in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

  18. Measurement of OH, H2SO4, MSA, and HNO3 Aboard the P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, F. L.

    2003-01-01

    This paper addresses the measurement of OH, H2SO4, MSA, and HNO3 aboard the P-3B aircraft under the following headings: 1) Performance Report; 2) Highlights of OH, H2SO4, and MSA Measurements Made Aboard the NASA P-3B During TRACE-P; 3) Development and characteristics of an airborne-based instrument used to measure nitric acid during the NASA TRACE-P field experiment.

  19. Counting Particles Emitted by Stratospheric Aircraft and Measuring Size of Particles Emitted by Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    There were two principal objectives of the cooperative agreement between NASA and the University of Denver. The first goal was to modify the design of the ER-2 condensation nuclei counter (CNC) so that the effective lower detection limit would be improved at high altitudes. This improvement was sought because, in the instrument used prior to 1993, diffusion losses prevented the smallest detectable particles from reaching the detection volume of the instrument during operation at low pressure. Therefore, in spite of the sensor's ability to detect particles as small as 0.008 microns in diameter, many of these particles were lost in transport to the sensing region and were not counted. Most of the particles emitted by aircraft are smaller than 0.1 micron in diameter. At the start date of this work, May 1990, continuous sizing techniques available on the ER-2 were only capable of detecting particles larger than 0.17 micron. Thus, the second objective of this work was to evaluate candidate sizing techniques in an effort to gain additional information concerning the size of particles emitted by aircraft.

  20. Measurement, analysis, and prediction of aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Howlett, J. T.; Williams, L. H.; Catherines, J. J.; Jha, S. K.

    1976-01-01

    Considerations of comfort of passengers and crew in light aircraft and helicopters indicate substantial benefits may be obtained by the reduction of interior noise levels. This paper discusses an ongoing research effort to reduce interior noise in such vehicles. Data from both field and laboratory studies for a light aircraft are presented. The laboratory data indicate that structural vibration is an efficient source of interior noise and should be considered in the reduction of interior noise. Flight data taken on a helicopter before and after installation of acoustic treatment demonstrate that over 30 dB of noise reduction can be obtained in certain portions of the spectra. However, subjective evaluations of the treated vehicle indicate that further reductions in interior noise are desirable. An existing interior noise prediction method which was developed for large jet transports was applied to study low-frequency noise in a light aircraft fuselage. The results indicate that improvements in the analytical model may be necessary for the prediction of interior noise of light aircraft.

  1. Aircraft measurements of the atmospheric electrical global circuit during the period 1971-1984

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1985-01-01

    This report will update an investigation of the global circuit conducted over the last 14 years through aircraft measurements of the variation of ionospheric potential and associated parameters. The data base included electric field, conductivity, and air-earth current density profiles from the tropics (25 deg N) to the Arctic (79 deg N). Almost all of the data have been obtained over the ocean to reduce noise associated with local generators, aerosols, and convection. Recently, two aircraft have been utilized to obtain, for the first time, quasi-periodic sets of simultaneous ionospheric potential (VI) soundings at remote locations and extending over time spans sufficiently long so that the universal time diurnal variation (Carnegie curve) could be observed. In additon, these measurements provided the first detection of the modulation of electric fields in the troposphere caused by the double vortex ionospheric convection pattern. Besides summarizing these measurements and comparing them to similar data obtained by other groups, this report discusses meteorological sources of error and criteria for determining if the global circuit is being measured rather than variations caused by local meteorological processes.

  2. In-situ Measurements of the Cosmic Radiation on the Aircraft Altitude over Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Lee, J.; Park, I.; Lee, J.; Oh, S.; Kim, Y. C.

    2014-12-01

    This study presents the comparison between the measured and modeled cosmic radiation on aircraft altitude over Korean peninsula. We performed the measurement with a radiation spectrometer, Liulin-6K on board a Republic of Korea (ROK) Air Force aircraft accomplishing the high-altitude (above 9 km) flight over Korea, and the modeled data was obtained from the operational modeling program, CARI-6M developed by FAA. A number of measurements for the flight mission at high-altitude have been executed to evaluate the exposed dose of cosmic radiation. Both the measured and the calculated data show that the exposed radiation dose enhances dramatically as the altitude increases. The results reveal that the exposed dose rate of aircrews at high-altitude flight is 2-3 orders of magnitude (1-2 mSv/hour) higher than the exposure rate at sea level. It is inferred that the annual total dose of radiation for the aircrews at high-altitude could be higher than the annually public limit (1 mSv) recommended by ICRP. Finally, since neutrons are the dominant components reflecting among total cosmic radiation above 9 km, we try to analyze the relationship between the neutron count from the neutron monitor on the ground and the effective dose from the on board spectrometer. Based on these results, it is suggested that the annual criterion and the proper managing procedure of exposed dose for the flight aircrews of ROK Air Force should be regulated.

  3. Measuring the turbulent wind vector with a weight-shift Microlight Aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Neidl, F.; Butterbach-Bahl, K.; Schmid, H. P.; Beyrich, F.; Zheng, X. H.; Foken, T.

    2009-09-01

    The Small Environmental Research Aircraft (SERA) D-MIFUs initial fields of application are aerosol / cloud and radiation transfer research. Therefore a comparatively slow (True Airspeed, TAS ~25 ms-1) but highly mobile microlight aircraft was envisaged. To broaden the application area of D-MIFU we explore whether the microlight can also be used for Eddy Covariance (EC) flux measurement. To obtain useful data sets for airborne EC a reliable turbulent Wind Vector (WV) measurement is a key requirement. Here we present methodology and results to calibrate and express performance and uncertainty of microlight based WV measurement. Specific attention is given to the influence of the flexible-wing weight-shift geometry on the WV measurement. For the WV measurement we equipped D-MIFU with a 70 cm long noseboom supporting a classical 5 hole probe and a fast 50 μm diameter thermocouple. An Inertial Navigation System (INS) supplies high accuracy ground speeds (Ï?=0.05 ms-1) and attitude angles (Ï?=0.03° , 0.1° respectively for heading). Data are stored with 10 Hz yielding a horizontal resolution of 2.5 m. The INS also allows to analyze aircraft dynamics such as 3d rotation rates and acceleration of the nacelle body. Further estimates for 3d acceleration of airfoil and noseboom are obtained at 100 Hz. The noseboom calibration coefficients under laboratory conditions were obtained by wind tunnel- and thermal bath measurements. To transfer these characteristics for in-flight conditions we carried out a series of flights with D-MIFU above the Boundary Layer under calm conditions. On basis of level flights at different power settings we were able to determine dynamic pressure-, sideslip- and attack angle offsets. Additionally forced maneuvers, such as e.g. phugoids, have been performed. By means of multivariate analysis these data are used to assess and minimize the impact of microlight nacelle and airfoil rapidly varying motions (RVM) on the WV components. In the final

  4. The LIULIN-3M Radiometer for Measuring Particle Doses in Space and on Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Tomov, B. T.; Dimitrov, P. G.; Brucker, G. J.; Obenschain, Art (Technical Monitor)

    2002-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  5. Measurements of Radiation Exposure on Commercial Aircraft with the LIULIN-3M Instrument

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Brucker, G. J.; Tomov, B. T.; Dimitrov, P. G.

    1998-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  6. The LIULIN-3M Radiometer for Measuring Particle Doses in Space and on Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Brucker, G. J.; Tomov, B. T.; Dimitrov, P. G.

    1999-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  7. Smart aircraft fastener evaluation (SAFE) system: a condition-based corrosion detection system for aging aircraft

    NASA Astrophysics Data System (ADS)

    Schoess, Jeffrey N.; Seifert, Greg; Paul, Clare A.

    1996-05-01

    The smart aircraft fastener evaluation (SAFE) system is an advanced structural health monitoring effort to detect and characterize corrosion in hidden and inaccessible locations of aircraft structures. Hidden corrosion is the number one logistics problem for the U.S. Air Force, with an estimated maintenance cost of $700M per year in 1990 dollars. The SAFE system incorporates a solid-state electrochemical microsensor and smart sensor electronics in the body of a Hi-Lok aircraft fastener to process and autonomously report corrosion status to aircraft maintenance personnel. The long-term payoff for using SAFE technology will be in predictive maintenance for aging aircraft and rotorcraft systems, fugitive emissions applications such as control valves, chemical pipeline vessels, and industrial boilers. Predictive maintenance capability, service, and repair will replace the current practice of scheduled maintenance to substantially reduce operational costs. A summary of the SAFE concept, laboratory test results, and future field test plans is presented.

  8. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Jones, C. R.; Mihelic, J. E.; Barnes, J. D.

    1998-01-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft's right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in- flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft's right main wheel fairing. Inspection results and techniques developed to verify the aircraft's structural integrity are discussed.

  9. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  10. Comparison of aircraft noise measured in flight test and in the NASA Ames 40- by 80-foot wind tunnel.

    NASA Technical Reports Server (NTRS)

    Atencio, A., Jr.; Soderman, P. T.

    1973-01-01

    A method to determine free-field aircraft noise spectra from wind-tunnel measurements has been developed. The crux of the method is the correction for reverberations. Calibrated loud speakers are used to simulate model sound sources in the wind tunnel. Corrections based on the difference between the direct and reverberant field levels are applied to wind-tunnel data for a wide range of aircraft noise sources. To establish the validity of the correction method, two research aircraft - one propeller-driven (YOV-10A) and one turbojet-powered (XV-5B) - were flown in free field and then tested in the wind tunnel. Corrected noise spectra from the two environments agree closely.

  11. Smart skin technology development for measuring ice accretion, stall, and high AOA aircraft performance. Part 1: Capacitive ice detector development

    NASA Technical Reports Server (NTRS)

    Pruzan, Daniel A.; Khatkhate, Ateen A.; Gerardi, Joseph J.; Hickman, Gail A.

    1993-01-01

    A reliable way to detect and measure ice accretion during flight is required to reduce the hazards of icing currently threatening present day aircraft. Many of the sensors used for this purpose are invasive (probe) sensors which must be placed in areas of the airframe where ice does not naturally form. Due to the difference in capture efficiency of the exposed surface, difficulties result in correlating the ice accretion on the probe to what is happening on a number of vastly different airfoil sections. Most flush mounted sensors in use must be integrated into the aircraft surface by cutting or drilling the aircraft surface. An alternate type of ice detector which is based on a NASA patent is currently being investigated at Innovative Dynamics, Inc. (IDI). Results of the investigation into the performance of different capacitive type sensor designs, both rigid as well as elastic, are presented.

  12. Display-based communications for advanced transport aircraft

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.

    1989-01-01

    The next generation of civil transport aircraft will depend increasingly upon ground-air-ground and satellite data link for information critical to safe and efficient air transportation. Previous studies which examined the concept of display-based communications in addition to, or in lieu of, conventional voice transmissions are reviewed. A full-mission flight simulation comparing voice and display-based communication modes in an advanced transport aircraft is also described. The results indicate that a display-based mode of information transfer does not result in significantly increased aircrew workload, but does result in substantially increased message acknowledgment times when compared to conventional voice transmissions. User acceptance of the display-based communication system was generally high, replicating the findings of previous studies. However, most pilots tested expressed concern over the potential loss of information available from frequency monitoring which might result from the introduction of discrete address communications. Concern was expressed by some pilots for the reduced time available to search for conflicting traffic when using the communications display system. The implications of the findings for the design of display-based communications are discussed.

  13. Spatial and temporal variation in CO over Alberta using measurements from satellites, aircraft, and ground stations

    NASA Astrophysics Data System (ADS)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J.

    2015-04-01

    Alberta is Canada's largest oil producer, and its oil sands deposits comprise 30% of the world's oil reserves. The process of bitumen extraction and upgrading releases trace gases and aerosols to the atmosphere. In this study we present satellite-based analysis to explore, for the first time, various contributing factors that affect tropospheric carbon monoxide (CO) levels over Alberta. The multispectral product that uses both near-infrared (NIR) and the thermal-infrared (TIR) radiances for CO retrieval from the Measurements of Pollution in the Troposphere (MOPITT) is examined for the 12-year period from 2002 to 2013. The Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly product from 2001 to 2013 is employed to investigate the seasonal and temporal variations in forest fires. Additionally, in situ CO measurements at industrial and urban sites are compared to satellite data. Furthermore, the available MOZAIC/IAGOS (Measurement of Ozone, Water Vapor, Carbon Monoxide, Nitrogen Oxide by Airbus In-Service Aircraft/In service Aircraft for Global Observing System) aircraft CO profiles (April 2009-December 2011) are used to validate MOPITT CO data. The climatological time curtain plot and spatial maps for CO over northern Alberta indicate the signatures of transported CO for two distinct biomass burning seasons: summer and spring. Distinct seasonal patterns of CO at the urban sites (Edmonton and Calgary) point to the strong influence of traffic. Meteorological parameters play an important role in the CO spatial distribution at various pressure levels. Northern Alberta shows a stronger upward lifting motion which leads to larger CO total column values, while the poor dispersion in central and southern Alberta exacerbates the surface CO pollution. Interannual variations in satellite data depict a slightly decreasing trend for both regions, while the decline trend is more evident from ground observations, especially at the urban sites. MOPITT CO vertical

  14. Spatial and temporal variation of CO over Alberta using measurements from satellite, aircrafts, and ground stations

    NASA Astrophysics Data System (ADS)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J.

    2014-12-01

    Alberta is Canada's largest oil producer and its oil sand deposits comprise 30% of the world's oil reserves. The process of bitumen extraction and upgrading releases trace gases and aerosols to the atmosphere. In this study we present satellite-based analysis to explore, for the first time, various contributing factors that affect tropospheric carbon monoxide (CO) levels over Alberta. The multispectral product that uses both near-infrared (NIR) and the thermal-infrared (TIR) radiances for CO retrieval from the Measurements of Pollution in the Troposphere (MOPITT) are examined for the 12 year period from 2002-2013. Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly product from 2001 to 2013 is employed to investigate the seasonal and temporal variations of forest fires. Additionally, in situ CO measurements at industrial and urban sites are compared to satellite data. Furthermore, the available MOZAIC/IAGOS (Measurement of Ozone, Water Vapor, Carbon Monoxide, Nitrogen Oxide by Airbus In-Service Aircraft/In service Aircraft for Global Observing System) aircraft CO profiles (April 2009-December 2011) are used to validate MOPITT CO data. The climatological time curtain plot and spatial maps for CO over northern Alberta indicate the signatures of transported CO for two distinct biomass burning seasons, summer and spring. Distinct seasonal patterns of CO at the urban site s (Edmonton and Calgary cities) point to the strong influence of traffic. Meteorological parameters play an important role on the CO spatial distribution at various pressure levels. Northern Alberta shows stronger upward lifting motion which leads to larger CO total column values while the poor dispersion in central and south Alberta exacerbates the surface CO pollution. Inter-annual variations of satellite data depict a slightly decreasing trend for both regions while the decline trend is more evident from ground observations, especially at the urban sites. MOPITT CO vertical

  15. Quasi-Static Viscoelasticity Loading Measurements of an Aircraft Tire

    NASA Technical Reports Server (NTRS)

    Mason, Angela J.; Tanner, John A.; Johnson, Arthur R.

    1997-01-01

    Stair-step loading, cyclic loading, and long-term relaxation tests were performed on an aircraft tire to observe the quasi-static viscoelastic response of the tire. The data indicate that the tire continues to respond viscoelastically even after it has been softened by deformation. Load relaxation data from the stair-step test at the 15,000-lb loading was fit to a monotonically decreasing Prony series.

  16. Aerosol emissions from prescribed fires in the United States: A synthesis of laboratory and aircraft measurements

    NASA Astrophysics Data System (ADS)

    May, A. A.; McMeeking, G. R.; Lee, T.; Taylor, J. W.; Craven, J. S.; Burling, I.; Sullivan, A. P.; Akagi, S.; Collett, J. L.; Flynn, M.; Coe, H.; Urbanski, S. P.; Seinfeld, J. H.; Yokelson, R. J.; Kreidenweis, S. M.

    2014-10-01

    Aerosol emissions from prescribed fires can affect air quality on regional scales. Accurate representation of these emissions in models requires information regarding the amount and composition of the emitted species. We measured a suite of submicron particulate matter species in young plumes emitted from prescribed fires (chaparral and montane ecosystems in California; coastal plain ecosystem in South Carolina) and from open burning of over 15 individual plant species in the laboratory. We report emission ratios and emission factors for refractory black carbon (rBC) and submicron nonrefractory aerosol and compare field and laboratory measurements to assess the representativeness of our laboratory-measured emissions. Laboratory measurements of organic aerosol (OA) emission factors for some fires were an order of magnitude higher than those derived from any of our aircraft observations; these are likely due to higher-fuel moisture contents, lower modified combustion efficiencies, and less dilution compared to field studies. Nonrefractory inorganic aerosol emissions depended more strongly on fuel type and fuel composition than on combustion conditions. Laboratory and field measurements for rBC were in good agreement when differences in modified combustion efficiency were considered; however, rBC emission factors measured both from aircraft and in the laboratory during the present study using the Single Particle Soot Photometer were generally higher than values previously reported in the literature, which have been based largely on filter measurements. Although natural variability may account for some of these differences, an increase in the BC emission factors incorporated within emission inventories may be required, pending additional field measurements for a wider variety of fires.

  17. Graphene-Based Ultra-Light Batteries for Aircraft

    NASA Technical Reports Server (NTRS)

    Calle, Carlos I.; Kaner, Richard B.

    2014-01-01

    Develop a graphene-based ultracapacitor prototype that is flexible, thin, lightweight, durable, low cost, and safe and that will demonstrate the feasibility for use in aircraft center dot These graphene-based devices store charge on graphene sheets and take advantage of the large accessible surface area of graphene (2,600 m2/g) to increase the electrical energy that can be stored. center dot The proposed devices should have the electrical storage capacity of thin-film-ion batteries but with much shorter charge/discharge cycle times as well as longer lives center dot The proposed devices will be carbon-based and so will not have the same issues with flammability or toxicity as the standard lithium-based storage cells There are two main established methods for the storage and delivery of electrical energy: center dot Batteries - Store energy with electrochemical reactions - High energy densities - Slow charge/discharge cycles - Used in applications requiring large amounts of energy ? aircraft center dot Electrochemical capacitors - Store energy in electrochemical double layers - Fast charge/discharge cycles - Low energy densities - Used in electronics devices - Large capacitors are used in truck engine cranking

  18. PM emissions measurements of in-service commercial aircraft engines during the Delta-Atlanta Hartsfield Study

    NASA Astrophysics Data System (ADS)

    Lobo, Prem; Hagen, Donald E.; Whitefield, Philip D.; Raper, David

    2015-03-01

    This paper describes the results of the physical characterization of aircraft engine PM emission measurements conducted during the Delta-Atlanta Hartsfield Study at the Hartsfield-Jackson Atlanta International Airport. Engine exit plane PM emissions were sampled from on-wing engines on several in-service commercial transport aircraft from the fleet of Delta Airlines. The size distributions were lognormal in nature with a single mode. The geometric mean diameter was found to increase with increasing engine thrust, ranging from 15 nm at idle to 40 nm at takeoff. PM number- and mass-based emission indices were observed to be higher at the idle conditions (4% and 7%), lowest at 15%-30% thrust, and then increase with increasing thrust. Emissions measurements were also conducted during an advected plume study where over 300 exhaust plumes generated by a broad mix of commercial transports were sampled 100-350 m downwind from aircraft operational runways during normal airport operations. The range of values measured at take-off for the different engine types in terms of PM number-based emission index was between 7 × 1015-9 × 1017 particles/kg fuel burned, and that for PM mass-based emission index was 0.1-0.6 g/kg fuel burned. PM characteristics of aircraft engine specific exhaust were found to evolve over time as the exhaust plume expands, dilutes with ambient air, and cools. The data from these measurements will enhance the emissions inventory development for a subset of engines operating in the commercial fleet and improve/validate current environmental impact predictive tools with real world aircraft engine specific PM emissions inputs.

  19. Knowledge-based processing for aircraft flight control

    NASA Technical Reports Server (NTRS)

    Painter, John H.; Glass, Emily; Economides, Gregory; Russell, Paul

    1994-01-01

    This Contractor Report documents research in Intelligent Control using knowledge-based processing in a manner dual to methods found in the classic stochastic decision, estimation, and control discipline. Such knowledge-based control has also been called Declarative, and Hybid. Software architectures were sought, employing the parallelism inherent in modern object-oriented modeling and programming. The viewpoint adopted was that Intelligent Control employs a class of domain-specific software architectures having features common over a broad variety of implementations, such as management of aircraft flight, power distribution, etc. As much attention was paid to software engineering issues as to artificial intelligence and control issues. This research considered that particular processing methods from the stochastic and knowledge-based worlds are duals, that is, similar in a broad context. They provide architectural design concepts which serve as bridges between the disparate disciplines of decision, estimation, control, and artificial intelligence. This research was applied to the control of a subsonic transport aircraft in the airport terminal area.

  20. Inefficiency of sanitation measures aboard commercial aircraft: environmental pollution and disease.

    PubMed

    Kikuchi, R

    1977-07-01

    Recent investigations at Tokyo International Airport have proven that environmental pollution resulting from the inefficient disposal of human excretion aboard aircraft is an important problem from the standpoint of quarantine. It is, therefore, recommended that the worldwide aviation industry take immediate measures to improve conditions and eliminate this problem, which has thus far been ignored by aircraft designers, airport administration, and CAB personnel. PMID:329830

  1. Aircraft and satellite measurement of ocean wave directional spectra using scanning-beam microwave radars

    NASA Technical Reports Server (NTRS)

    Jackson, F. C.; Walton, W. T.; Baker, P. L.

    1982-01-01

    A microwave radar technique for remotely measuring the vector wave number spectrum of the ocean surface is described. The technique, which employs short-pulse, noncoherent radars in a conical scan mode near vertical incidence, is shown to be suitable for both aircraft and satellite application, the technique was validated at 10 km aircraft altitude, where we have found excellent agreement between buoy and radar-inferred absolute wave height spectra.

  2. A snapshot of the UK net greenhouse gas flux using a mass balance approach with aircraft measurements

    NASA Astrophysics Data System (ADS)

    Allen, G.; Pitt, J. R.; Palmer, P. I.; Percival, C.; Mead, M. I.; Lee, J. D.; Le Breton, M. R.

    2015-12-01

    We present airborne observations of high-precision in-situ and remotely sensed CO2, CH4 and other trace gases made from the NERC Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft during Spring and Summer months in 2014 and 2015. Measurements were recorded during the GAUGE (Greenhouse gAs Uk and Global Emissions) aircraft field campaign, based out of Cranfield, UK, with sampling around and over the UK Mainland and Ireland. We derive Lagrangian mass-balanced net surface fluxes of CO2, CH4, CO, and N2O from a large surface footprint of England based on data collected during a flight in May 2015 by combining in-situ and remote-sensed concentration measurements and measured boundary layer thermodynamic profiles. By employing an advective box model for the volume enclosed by the flight-tracks and combining aircraft-measured winds and along-track Lagrangian back-trajectory modelling, we examine the sensitivity of total flux uncertainty to atmospheric transport and measurement errors using error propagation implicit in the mass balancing method. Finally, we compare the measured snapshot net fluxes to those reported in the current UK emissions inventory (weighted for surface footprint) and to previous UK-regional greenhouse gas top-down assessments.

  3. Large-Eddy Simulations and Lidar Measurements of Vortex-Pair Breakup in Aircraft Wakes

    NASA Technical Reports Server (NTRS)

    Lewellen, D. C.; Lewellen, W. S.; Poole, L. R.; DeCoursey, R. J.; Hansen, G. M.; Hostetler, C. A.; Kent, G. S.

    1998-01-01

    Results of large-eddy simulations of an aircraft wake are compared with results from ground-based lidar measurements made at NASA Langley Research Center during the Subsonic Assessment Near-Field Interaction Flight Experiment field tests. Brief reviews of the design of the field test for obtaining the evolution of wake dispersion behind a Boeing 737 and of the model developed for simulating such wakes are given. Both the measurements and the simulations concentrate on the period from a few seconds to a few minutes after the wake is generated, during which the essentially two-dimensional vortex pair is broken up into a variety of three-dimensional eddies. The model and experiment show similar distinctive breakup eddies induced by the mutual interactions of the vortices, after perturbation by the atmospheric motions.

  4. Sulfur Dioxide Measurements Near Point Sources Using Ultraviolet Spectroscopy From Aircraft During ICARTT-2004

    NASA Astrophysics Data System (ADS)

    Melamed, M. L.; Langford, A. O.; Daniel, J. S.; Miller, H. L.; Portmann, R. W.; Schofield, R.; Solomon, S.

    2005-12-01

    Accurate measurements of sulfur dioxide are important in urban air pollution studies due to the role sulfur dioxide plays in atmospheric processes such as acid rain and particle formation. We will show slant column sulfur dioxide abundances that were derived using the differential optical absorption spectroscopy (DOAS) technique with ultraviolet spectrograph measurements taken aboard the NOAA WP-3D aircraft during ICARTT-2004. The spectrograph has zenith and nadir fields of view allowing for measurements of the pollution plume independent of the aircraft altitude and the height and uniformity of the boundary layer. A short integration time yields a high frequency measurement in order to distinguish localized pollution plumes from surrounding air. The sulfur dioxide slant column abundances show good qualitative agreement when compared to sulfur dioxide in-situ measurements aboard the same aircraft.

  5. Differences in Characteristics of Aviation Accidents During 1993-2012 Based on Aircraft Type

    NASA Technical Reports Server (NTRS)

    Evans, Joni K.

    2015-01-01

    Civilian aircraft are available in a variety of sizes, engine types, construction materials and instrumentation complexity. For the analysis reported here, eleven aircraft categories were developed based mostly on aircraft size and engine type, and these categories were applied to twenty consecutive years of civil aviation accidents. Differences in various factors were examined among these aircraft types, including accident severity, pilot characteristics and accident occurrence categories. In general, regional jets and very light sport aircraft had the lowest rates of adverse outcomes (injuries, fatal accidents, aircraft destruction, major accidents), while aircraft with twin (piston) engines or with a single (piston) engine and retractable landing gear carried the highest incidence of adverse outcomes. The accident categories of abnormal runway contact, runway excursions and non-powerplant system/component failures occur frequently within all but two or three aircraft types. In contrast, ground collisions, loss of control - on ground/water and powerplant system/component failure occur frequently within only one or two aircraft types. Although accidents in larger aircraft tend to have less severe outcomes, adverse outcome rates also differ among accident categories. It may be that the type of accident has as much or more influence on the outcome as the type of aircraft.

  6. Investigation of a laser Doppler velocimeter system to measure the flow field around a large scale V/STOL aircraft in ground effect

    NASA Technical Reports Server (NTRS)

    Zalay, A. D.; Brashears, M. R.; Jordan, A. J.; Shrider, K. R.; Vought, C. D.

    1979-01-01

    The flow field measured around a hovering 70 percent scale vertical takeoff and landing (V/STOL) aircraft model is described. The velocity measurements were conducted with a ground based laser Doppler velocimeter. The remote sensing instrumentation and experimental tests of the velocity surveys are discussed. The distribution of vertical velocity in the fan jet and fountain; the radial velocity in the wall jet and the horizontal velocity along the aircraft underside are presented for different engine rpms and aircraft height above ground. Results show that it is feasible to use a mobile laser Doppler velocimeter to measure the flow field generated by a large scale V/STOL aircraft operating in ground effect.

  7. Investigation of a laser Doppler velocimeter system to measure the flow field of a large scale V/STOL aircraft in ground effect

    NASA Technical Reports Server (NTRS)

    Zalay, A. D.; Brashears, M. R.; Jordan, A. J.; Shrider, K. R.; Vought, C. D.

    1979-01-01

    An experimental research program for measuring the flow field around a 70 percent scale V/STOL aircraft model in ground effect is described. The velocity measurements were conducted with a ground-based laser Doppler velocimeter at an outdoor test pad. The remote sensing instrumentation, experimental tests, and results of the velocity surveys are discussed. The distribution of vertical velocity in the fan jet and fountain, the radial velocity in the wall jet and the horizontal velocity along the aircraft underside are presented for different engine rpms and aircraft heights above ground. The study shows that it is feasible to use a mobile laser Doppler velocimeter to measure the flow field generated by a large scale V/STOL aircraft operating in ground effect.

  8. Insect vision based collision avoidance system for Remotely Piloted Aircraft

    NASA Astrophysics Data System (ADS)

    Jaenisch, Holger; Handley, James; Bevilacqua, Andrew

    2012-06-01

    Remotely Piloted Aircraft (RPA) are designed to operate in many of the same areas as manned aircraft; however, the limited instantaneous field of regard (FOR) that RPA pilots have limits their ability to react quickly to nearby objects. This increases the danger of mid-air collisions and limits the ability of RPA's to operate in environments such as terminals or other high-traffic environments. We present an approach based on insect vision that increases awareness while keeping size, weight, and power consumption at a minimum. Insect eyes are not designed to gather the same level of information that human eyes do. We present a novel Data Model and dynamically updated look-up-table approach to interpret non-imaging direction sensing only detectors observing a higher resolution video image of the aerial field of regard. Our technique is a composite hybrid method combining a small cluster of low resolution cameras multiplexed into a single composite air picture which is re-imaged by an insect eye to provide real-time scene understanding and collision avoidance cues. We provide smart camera application examples from parachute deployment testing and micro unmanned aerial vehicle (UAV) full motion video (FMV).

  9. Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction

    NASA Technical Reports Server (NTRS)

    Olson, Erik D.; Mavris, Dimitri N.

    2006-01-01

    An approach was developed which allows for design studies of commercial aircraft using physics-based noise analysis methods while retaining the ability to perform the rapid trade-off and risk analysis studies needed at the conceptual design stage. A prototype integrated analysis process was created for computing the total aircraft EPNL at the Federal Aviation Regulations Part 36 certification measurement locations using physics-based methods for fan rotor-stator interaction tones and jet mixing noise. The methodology was then used in combination with design of experiments to create response surface equations (RSEs) for the engine and aircraft performance metrics, geometric constraints and take-off and landing noise levels. In addition, Monte Carlo analysis was used to assess the expected variability of the metrics under the influence of uncertainty, and to determine how the variability is affected by the choice of engine cycle. Finally, the RSEs were used to conduct a series of proof-of-concept conceptual-level design studies demonstrating the utility of the approach. The study found that a key advantage to using physics-based analysis during conceptual design lies in the ability to assess the benefits of new technologies as a function of the design to which they are applied. The greatest difficulty in implementing physics-based analysis proved to be the generation of design geometry at a sufficient level of detail for high-fidelity analysis.

  10. A measurement model for general noise reaction in response to aircraft noise.

    PubMed

    Kroesen, Maarten; Schreckenberg, Dirk

    2011-01-01

    In this paper a measurement model for general noise reaction (GNR) in response to aircraft noise is developed to assess the performance of aircraft noise annoyance and a direct measure of general reaction as indicators of this concept. For this purpose GNR is conceptualized as a superordinate latent construct underlying particular manifestations. This conceptualization is empirically tested through estimation of a second-order factor model. Data from a community survey at Frankfurt Airport are used for this purpose (N=2206). The data fit the hypothesized factor structure well and support the conceptualization of GNR as a superordinate construct. It is concluded that noise annoyance and a direct measure of general reaction to noise capture a large part of the negative feelings and emotions in response to aircraft noise but are unable to capture all relevant variance. The paper concludes with recommendations for the valid measurement of community reaction and several directions for further research.

  11. Long-term airborne black carbon measurements on a Lufthansa passenger aircraft

    NASA Astrophysics Data System (ADS)

    Ditas, Jeannine; Su, Hang; Scharffe, Dieter; Wang, Siwen; Zhang, Yuxuan; Brenninkmeijer, Carl; Pöschl, Ulrich; Cheng, Yafang

    2016-04-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO² the strongest component of current global warming (Bond, 2013). Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free and upper troposphere, and in the UTLS (upper troposphere and lower stratosphere). Many models underestimate the global atmospheric absorption attributable to black carbon by a factor of almost 3 (Bond, 2013). In August 2014, a single particle soot photometer was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 (with an interruption for 2002-2005) and carries out systematic observations at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The container has equipment for trace gas analyses and sampling and aerosol analyses and sampling and is connected to an inlet system that is part of the aircraft which contains a camera and DOAS remote sensing system. The integration of a single particle soot photometer (SP2) offers the possibility for the first long-term measurement of global distribution of black carbon and so far flights up to November 2015 have been conducted with more than 400 flight hours. So far the SP2 measurements have been analysed for flights over four continents from Munich to San Francisco, Sao Paulo, Tokyo, Beijing, Cape Town, Los Angeles and Hong Kong). The first measurements show promising results of black carbon measurements. Background concentrations in the UTLS

  12. The pushbroom microwave radiometer and aircraft measurement of soil moisture

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Lawrence, R. W.; Levine, J. S.; Delnore, V. E.

    1985-01-01

    Soil moisture has been identified as a controlling parameter in the occurrence of atmospheric variations and crop vigor. Evapotranspiration rates impact local temperature, precipitation and motion fields of the atmosphere. The multiple beam pushbroom microwave radiometer (MBPMR) is a candidate for moisture monitoring on the Earth Observation System. A prototype MBPMR has been devised for airborne technology evaluations of pushbroom scanning capabilities. The instrument scans at 1.4 GHz with a Diche radiometer. Test flights on a NASA aircraft with the antenna mounted on the bottom of the fuselage have generated soil moisture data over crop areas for which ground truth data were gathered. Large antennas deployed from the Orbiter could collect sufficient data for mapping the global soil moisture in 6 days.

  13. An aircraft instrument design for in situ tropospheric OH measurements by laser induced fluorescence at low pressures

    NASA Technical Reports Server (NTRS)

    Brune, William H.; Stevens, Philip S.; Mather, James H.

    1993-01-01

    The hydroxyl radical (OH) is important for many processes involved in tropospheric chemistry. For instance, it initiates the photochemical degradation of gases that cause global climate change, such as methane and the chlorofluorocarbon substitutes (HCFCs). Because of its reactivity, its abundances are less than 0.1 pptv. Thus, OH has been very difficult to measure accurately, despite its importance. Techniques have evolved, however, so that good measurements of tropospheric OH abundances are now possible. One of these techniques that is adaptable to aircraft measurements is the laser induced fluorescence detection of the OH radical in a detection chamber at low pressures. The current ground-based instrument, which can be readily adapted to aircraft, can detect OH abundances of 1.4 x 10 exp 5 OH molecules/cu cm with S/N = 2 in 30 sec, and 5 x 10 exp 4/cu cm in 5 min.

  14. Measurement and analysis of aircraft and vehicle LRCS in outfield test

    NASA Astrophysics Data System (ADS)

    Cao, Chang-Qing; Zeng, Xiao-dong; Fan, Zhao-jin; Feng, Zhe-jun; Lai, Zhi

    2015-04-01

    The measurement of aircraft and vehicle Laser Radar Cross Section (LRCS) is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering. A brief introduction of the measuring theory of the laser scattering from the full-scale aircraft and vehicle targets is presented in this paper. By analyzing the measuring condition in outfield test, the laser systems and test steps are designed for full-scale aircraft and vehicle LRCS and verified by the experiment in laboratory. The processing data error 7% below is obtained of the laser radar cross section by using Gaussian compensation and elimination of sky background for original test data. The study of measurement and analysis proves that the proposed method is effective and correct to get laser radar cross section data in outfield test. The objectives of this study were: (1) to develop structural concepts for different LRCS fuselage configurations constructed of conventional materials; (2) to compare these findings with those of aircrafts or vehicles; (3) to assess the application of advanced materials for each configuration; (4) to conduct an analytical investigation of the aerodynamic loads, vertical drag and mission performance of different LRCS configurations; and (5) to compare these findings with those of the aircrafts or vehicles.

  15. Thermodynamic correction of particle concentrations measured by underwing probes on fast flying aircraft

    NASA Astrophysics Data System (ADS)

    Weigel, R.; Spichtinger, P.; Mahnke, C.; Klingebiel, M.; Afchine, A.; Petzold, A.; Krämer, M.; Costa, A.; Molleker, S.; Jurkat, T.; Minikin, A.; Borrmann, S.

    2015-12-01

    Particle concentration measurements with underwing probes on aircraft are impacted by air compression upstream of the instrument body as a function of flight velocity. In particular for fast-flying aircraft the necessity arises to account for compression of the air sample volume. Hence, a correction procedure is needed to invert measured particle number concentrations to ambient conditions that is commonly applicable for different instruments to gain comparable results. In the compression region where the detection of particles occurs (i.e. under factual measurement conditions), pressure and temperature of the air sample are increased compared to ambient (undisturbed) conditions in certain distance away from the aircraft. Conventional procedures for scaling the measured number densities to ambient conditions presume that the particle penetration speed through the instruments' detection area equals the aircraft speed (True Air Speed, TAS). However, particle imaging instruments equipped with pitot-tubes measuring the Probe Air Speed (PAS) of each underwing probe reveal PAS values systematically below those of the TAS. We conclude that the deviation between PAS and TAS is mainly caused by the compression of the probed air sample. From measurements during two missions in 2014 with the German Gulfstream G-550 (HALO - High Altitude LOng range) research aircraft we develop a procedure to correct the measured particle concentration to ambient conditions using a thermodynamic approach. With the provided equation the corresponding concentration correction factor ξ is applicable to the high frequency measurements of each underwing probe which is equipped with its own air speed sensor (e.g. a pitot-tube). ξ-values of 1 to 0.85 are calculated for air speeds (i.e. TAS) between 60 and 260 m s-1. From HALO data it is found that ξ does not significantly vary between the different deployed instruments. Thus, for the current HALO underwing probe configuration a parameterisation of

  16. Performance degradation of a typical twin engine commuter type aircraft in measured natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Perkins, P. J., Jr.

    1984-01-01

    The performance of an aircraft in various measured icing conditions was investigated. Icing parameters such as liquid water content, temperature, cloud droplet sizes and distributions were measured continuously while in icing. Flight data were reduced to provide plots of the aircraft drag polars and lift curves (CL vs. alpha) for the measured ""iced'' condition as referenced to the uniced aircraft. These data were also reduced to provide plots of thrust horsepower required vs. single engine power available to show how icing affects engine out capability. It is found that performance degradation is primarily influenced by the amount and shape of the accumulated ice. Glaze icing caused the greatest aerodynamic performance penalties in terms of increased drag and reduction in lift while aerodynamic penalties due to rime icing were significantly lower.

  17. ACE 1992 summary data report: Aircraft measurements of meteorological parameters and SF6. Technical memo

    SciTech Connect

    Watkins, B.A.; Boatman, J.F.; Wellman, D.L.; Wilkison, S.W.

    1993-02-01

    Meteorological parameters and sulfur hexafluoride (SF6) were measured with the NOAA King Air C-90 aircraft during October 1992 in central Florida as part of the Air Force Technical Applications Command (AFTAC) Airborne Collection Equipment (ACE 1992) experiment. Airborne sampling was used to locate a plume containing SF6 as a tracer. Before take off, a trajectory model was used to provide the expected plume path. An onboard tracking program gave current predictions of the location of the plume, based on the location of tetroons expected to travel with the plume. Once the plume was located, samples were collected of triethyl phosphate oxide and methyl salicylate, which had been released with the SF6. This report discusses the objectives of ACE 1992, the instrumentation used and the data obtained by the NOAA King Air ground and airborne operation.

  18. Calibration and demonstration of a condensation nuclei counting system for airborne measurements of aircraft exhausted particles

    NASA Astrophysics Data System (ADS)

    Cofer, Wesley R.; Anderson, Bruce E.; Winstead, Edward L.; Bagwell, Donald R.

    A system of multiple continuous-flow condensation nuclei counters (CNC) was assembled, calibrated, and demonstrated on a NASA T-39 Sabreliner jet aircraft. The mission was to penetrate the exhaust plumes and/or contrails of other subsonic jet aircraft and determine the concentrations of submicrometer diameter aerosol particles. Mission criteria required rapid response measurements ( ˜ 1 s) at aircraft cruise altitudes (9-12 km). The CNC sampling system was optimized to operate at 160 Torr. Aerosol samples were acquired through an externally mounted probe. Installed downstream of the probe was a critical flow orifice that provided sample to the CNC system. The orifice not only controlled volumetric flow rate, but also dampened probe pressure/flow oscillations encountered in the turbulent aircraft-wake vortex environment. Laboratory calibrations with NaCl particles under representative conditions are reported that indicate small amounts of particle loss and a maximum measurement efficiency of ˜ 75% for particles with diameters ranging from ⩾ 0.01- ⩽ 0.18 μm Data from exhaust/contrail samplings of a NASA B757 and DC-8 at cruise altitude are discussed. Data include exhaust/contrail measurements made during periods in which the B757 port jet engine burned low-sulfur fuel while the starboard engine simultaneously burned specially prepared high-sulfur fuel. The data discussed highlight the CNC systems performance, and introduce new observations pertinent to the behavior of sulfur in aircraft exhaust aerosol chemistry.

  19. NO and NOy in the upper troposphere: Nine years of CARIBIC measurements onboard a passenger aircraft

    NASA Astrophysics Data System (ADS)

    Stratmann, G.; Ziereis, H.; Stock, P.; Brenninkmeijer, C. A. M.; Zahn, A.; Rauthe-Schöch, A.; Velthoven, P. V.; Schlager, H.; Volz-Thomas, A.

    2016-05-01

    Nitrogen oxide (NO and NOy) measurements were performed onboard an in-service aircraft within the framework of CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). A total of 330 flights were completed from May 2005 through April 2013 between Frankfurt/Germany and destination airports in Canada, the USA, Brazil, Venezuela, Chile, Argentina, Colombia, South Africa, China, South Korea, Japan, India, Thailand, and the Philippines. Different regions show differing NO and NOy mixing ratios. In the mid-latitudes, observed NOy and NO generally shows clear seasonal cycles in the upper troposphere with a maximum in summer and a minimum in winter. Mean NOy mixing ratios vary between 1.36 nmol/mol in summer and 0.27 nmol/mol in winter. Mean NO mixing ratios range between 0.05 nmol/mol and 0.22 nmol/mol. Regions south of 40°N show no consistent seasonal dependence. Based on CO observations, low, median and high CO air masses were defined. According to this classification, more data was obtained in high CO air masses in the regions south of 40°N compared to the midlatitudes. This indicates that boundary layer emissions are more important in these regions. In general, NOy mixing ratios are highest when measured in high CO air masses. This dataset is one of the most comprehensive NO and NOy dataset available today for the upper troposphere and is therefore highly suitable for the validation of atmosphere-chemistry-models.

  20. NO and NOy in the upper troposphere: Nine years of CARIBIC measurements onboard a passenger aircraft

    NASA Astrophysics Data System (ADS)

    Stratmann, G.; Ziereis, H.; Stock, P.; Brenninkmeijer, C. A. M.; Zahn, A.; Rauthe-Schöch, A.; Velthoven, P. V.; Schlager, H.; Volz-Thomas, A.

    2016-05-01

    Nitrogen oxide (NO and NOy) measurements were performed onboard an in-service aircraft within the framework of CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). A total of 330 flights were completed from May 2005 through April 2013 between Frankfurt/Germany and destination airports in Canada, the USA, Brazil, Venezuela, Chile, Argentina, Colombia, South Africa, China, South Korea, Japan, India, Thailand, and the Philippines. Different regions show differing NO and NOy mixing ratios. In the mid-latitudes, observed NOy and NO generally shows clear seasonal cycles in the upper troposphere with a maximum in summer and a minimum in winter. Mean NOy mixing ratios vary between 1.36 nmol/mol in summer and 0.27 nmol/mol in winter. Mean NO mixing ratios range between 0.05 nmol/mol and 0.22 nmol/mol. Regions south of 40°N show no consistent seasonal dependence. Based on CO observations, low, median and high CO air masses were defined. According to this classification, more data was obtained in high CO air masses in the regions south of 40°N compared to the midlatitudes. This indicates that boundary layer emissions are more important in these regions. In general, NOy mixing ratios are highest when measured in high CO air masses. This dataset is one of the most comprehensive NO and NOy dataset available today for the upper troposphere and is therefore highly suitable for the validation of atmosphere-chemistry-models.

  1. Long-term Airborne Black Carbon Measurements on a Lufthansa Passenger Aircraft

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, H.; Ditas, J.; Scharffe, D.; Wang, S.; Zhang, Y.; McMeeking, G. R.; Brenninkmeijer, C. A. M.; Poeschl, U.

    2015-12-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO2 the strongest component of current global warming. Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free troposphere, and in the UTLS (upper troposphere and lower stratosphere). In August 2014, a single particle soot photometer (SP2) was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 and carries out systematic observations of trace gas and aerosol sampling and on-line analyses, as well as DOAS remote sensing system at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The integration of a SP2 offers the possibility for the first long-term measurement of global distribution of black carbon. Up to date the SP2 measurements have been analyzed for 392 flights hours over four continents (Fig. 1). The first measurements show promising results of black carbon including periods when background concentrations in the UTLS were encountered. Beside a general distribution of number and mass of black carbon particles, peak events were detected with up to 20 times higher concentrations compared to the background. Moreover, high concentration plumes have been observed continuously over a range of 10,000 km. Interestingly, our results show also a generally lower amount of black carbon mass in the tropics compared to the mid latitude northern hemisphere.

  2. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    NASA Technical Reports Server (NTRS)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  3. Aircraft measurements of electrified clouds at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.

    1990-01-01

    The space-vehicle launch commit criteria for weather and atmospheric electrical conditions in us at Cape Canaveral Air Force Station and Kennedy Space Center (KSC) have been made restrictive because of the past difficulties that have arisen when space vehicles have triggered lightning discharge after their launch during cloudy weather. With the present ground-base instrumentation and our limited knowledge of cloud electrification process over this region of Florida, it has not been possible to provide a quantitative index of safe launching conditions. During the fall of 1988, a Schweizer 845 airplane equipped to measure electric field and other meteorological parameters flew over KSC in a program to study clouds defined in the existing launch restriction criteria. All aspects of this program are addressed including planning, method, and results. A case study on the November 4, 1988 flight is also presented.

  4. Fuel level sensor based on polymer optical fiber Bragg gratings for aircraft applications

    NASA Astrophysics Data System (ADS)

    Marques, C. A. F.; Pospori, A.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

    2016-04-01

    Safety in civil aviation is increasingly important due to the increase in flight routes and their more challenging nature. Like other important systems in aircraft, fuel level monitoring is always a technical challenge. The most frequently used level sensors in aircraft fuel systems are based on capacitive, ultrasonic and electric techniques, however they suffer from intrinsic safety concerns in explosive environments combined with issues relating to reliability and maintainability. In the last few years, optical fiber liquid level sensors (OFLLSs) have been reported to be safe and reliable and present many advantages for aircraft fuel measurement. Different OFLLSs have been developed, such as the pressure type, float type, optical radar type, TIR type and side-leaking type. Amongst these, many types of OFLLSs based on fiber gratings have been demonstrated. However, these sensors have not been commercialized because they exhibit some drawbacks: low sensitivity, limited range, long-term instability, or limited resolution. In addition, any sensors that involve direct interaction of the optical field with the fuel (either by launching light into the fuel tank or via the evanescent field of a fiber-guided mode) must be able to cope with the potential build up of contamination - often bacterial - on the optical surface. In this paper, a fuel level sensor based on microstructured polymer optical fiber Bragg gratings (mPOFBGs), including poly (methyl methacrylate) (PMMA) and TOPAS fibers, embedded in diaphragms is investigated in detail. The mPOFBGs are embedded in two different types of diaphragms and their performance is investigated with aviation fuel for the first time, in contrast to our previous works, where water was used. Our new system exhibits a high performance when compared with other previously published in the literature, making it a potentially useful tool for aircraft fuel monitoring.

  5. Counting particles emitted by stratospheric aircraft and measuring size of particles emitted by stratospheric aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    The ER-2 condensation nuclei counter (CNC) has been modified to reduce the diffusive losses of particles within the instrument. These changes have been successful in improving the counting efficiency of small particles at low pressures. Two techniques for measuring the size distributions of particles with diameters less than 0.17 micrometers have been evaluated. Both of these methods, the differential mobility analyzer (DMA) and the diffusion battery, have fundamental problems that limit their usefulness for stratospheric applications. We cannot recommend either for this application. Newly developed, alternative methods for measuring small particles include inertial separation with a low-loss critical orifice and thin-plate impactor device. This technique is now used to collect particles in the multisample aerosol collector housed in the ER-2 CNC-2, and shows some promise for particle size measurements when coupled with a CNC as a counting device. The modified focused-cavity aerosol spectrometer (FCAS) can determine the size distribution of particles with ambient diameters as small as about 0.07 micrometers. Data from this instrument indicates the presence of a nuclei mode when CNC-2 indicates high concentrations of particles, but cannot resolve important parameters of the distribution.

  6. The NASA Airborne Tropical TRopopause EXperiment (ATTREX):High-Altitude Aircraft Measurements in the Tropical Western Pacific

    NASA Technical Reports Server (NTRS)

    Jensen, E. J.; Pfister, L.; Jordan, D. E.; Bui, T. V.; Ueyama, R.; Singh, H. B.; Lawson, P.; Thornberry, T.; Diskin, G.; McGill, M.; Pittman, J.; Atlas, E.; Kim, J.

    2016-01-01

    The February through March 2014 deployment of the NASA Airborne Tropical TRopopause EXperiment (ATTREX) provided unique in situ measurements in the western Pacific Tropical Tropopause Layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the CONTRAST and CAST airborne campaigns based in Guam using lower-altitude aircraft The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes as well as for evaluation and improvement of global-model representations of TTL processes.

  7. Visualization of gust gradients and aircraft response as measured by the NASA B-57B aircraft

    NASA Technical Reports Server (NTRS)

    Camp, D.; Campbell, W.; Dow, C.; Phillips, M.; Gregory, R.; Frost, W.

    1984-01-01

    A program to obtain gust gradient measurements over the span of an airfoil is being conducted by NASA. Data have been collected from four areas of the United States (Denver, Colorado; Edwards, California; Huntsville, Alabama; and Norman, Oklahoma). The background program development data collection, and some data analysis efforts of the gust gradient effort have previously been presented (Houbolt, 1979; Camp, et al., 1983; Campbell, 1983; Campbell, et al., 1983; Frost, et al., 1983; and Painter and Camp, 1983). The purpose of this paper is to discuss briefly the animation of a gust gradient data set that was collected during the summer of 1982 at Denver, Colorado.

  8. Summary of aircraft results for 1978 southeastern Virginia urban plume measurement study of ozone, nitrogen oxides, and methane

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Wornom, D. E.; Mathis, J. J., Jr.; Sebacher, D. I.

    1980-01-01

    Ozone production was determined from aircraft and surface in situ measurements, as well as from an airborne laser absorption spectrometer. Three aircraft and approximately 10 surface stations provided air-quality data. Extensive meteorological, mixing-layer-height, and ozone-precursor data were also measured. Approximately 50 hrs (9 flight days) of data from the aircraft equipped to monitor ozone, nitrogen oxides, dewpoint temperature, and temperature are presented. In addition, each experiment conducted is discussed.

  9. A NASA study of the impact of technology on future carrier based tactical aircraft - Overview

    NASA Technical Reports Server (NTRS)

    Wilson, S. B., III

    1992-01-01

    This paper examines the impact of technology on future carrier based tactical aircraft. The results were used in the Center for Naval Analysis Future Carrier Study. The NASA Team designed three classes of aircraft ('Fighter', 'Attack', and 'Multimission') with two different technology levels. The Multimission aircraft were further analyzed by examining the penalty on the aircraft for both catapult launch/arrested landing recovery (Cat/trap) and short take-off/vertical landing (STOVL). The study showed the so-called STOVL penalty was reduced by engine technology and the next generation Strike Fighter will pay more penalty for Cat/trap than for STOVL capability.

  10. A traveling-salesman-based approach to aircraft scheduling in the terminal area

    NASA Technical Reports Server (NTRS)

    Luenberger, Robert A.

    1988-01-01

    An efficient algorithm is presented, based on the well-known algorithm for the traveling salesman problem, for scheduling aircraft arrivals into major terminal areas. The algorithm permits, but strictly limits, reassigning an aircraft from its initial position in the landing order. This limitation is needed so that no aircraft or aircraft category is unduly penalized. Results indicate, for the mix of arrivals investigated, a potential increase in capacity in the 3 to 5 percent range. Furthermore, it is shown that the computation time for the algorithm grows only linearly with problem size.

  11. A Systematic Approach for Model-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2010-01-01

    A requirement for effective aircraft engine performance estimation is the ability to account for engine degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. This paper presents a linear point design methodology for minimizing the degradation-induced error in model-based aircraft engine performance estimation applications. The technique specifically focuses on the underdetermined estimation problem, where there are more unknown health parameters than available sensor measurements. A condition for Kalman filter-based estimation is that the number of health parameters estimated cannot exceed the number of sensed measurements. In this paper, the estimated health parameter vector will be replaced by a reduced order tuner vector whose dimension is equivalent to the sensed measurement vector. The reduced order tuner vector is systematically selected to minimize the theoretical mean squared estimation error of a maximum a posteriori estimator formulation. This paper derives theoretical estimation errors at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared to the estimation accuracy achieved through conventional maximum a posteriori and Kalman filter estimation approaches. Maximum a posteriori estimation results demonstrate that reduced order tuning parameter vectors can be found that approximate the accuracy of estimating all health parameters directly. Kalman filter estimation results based on the same reduced order tuning parameter vectors demonstrate that significantly improved estimation accuracy can be achieved over the conventional approach of selecting a subset of health parameters to serve as the tuner vector. However, additional development is necessary to fully extend the methodology to Kalman filter-based

  12. A strategy for in-flight measurements of physiology of pilots of high-performance fighter aircraft.

    PubMed

    West, John B

    2013-07-01

    Some pilots flying modern high-performance fighter aircraft develop "hypoxia-like" incidents characterized by short periods of confusion and cognitive impairment. The problem is serious and recently led to the grounding of a fleet of aircraft. Extensive discussions of the incidents have taken place but some people believe that there is inadequate data to determine the cause. There is a tremendous disconnect between what is known about the function of the aircraft and the function of the pilot. This paper describes a plan for measuring the inspired and expired Po2 and Pco2 in the pilot's mask, the inspiratory flow rate, and pressure in the mask. A critically important requirement is that the interference with the function of the pilot is minimal. Although extensive physiological measurements were previously made on pilots in ground-based experiments such as rapid decompression in an altitude chamber and increased acceleration on a centrifuge, in-flight measurements of gas exchange have not been possible until now primarily because of the lack of suitable equipment. The present paper shows how the recent availability of small, rapidly responding oxygen and carbon dioxide analyzers make sophisticated in-flight measurements feasible. The added information has the potential of greatly improving our knowledge of pilot physiology, which could lead to an explanation for the incidents.

  13. Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyuk; Park, Yurim; Kim, Yoon-Young; Shrestha, Pratik; Kim, Chun-Gon

    2015-10-01

    This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.

  14. Oceanographic measurement capabilities of the NASA P-3 aircraft. [ERS-1 mission

    NASA Technical Reports Server (NTRS)

    Mollo-Christensen, Erik; Jackson, F. C.; Walsh, E. J.; Hoge, F.

    1986-01-01

    Instrumentation on NASA P3 aircraft available to provide ground truth for ERS-1 is described. The wave sensors include the 36 GHz Surface Contour Radar (SCR), the Ku-band Radar Ocean Wave Spectrometer (ROWS), and the Airborne Oceanographic Lidar. The other sensors include a C-band scatterometer, video camera, radiation thermometer, and AXRTs. The SCR and ROWS directional spectrum measurements are discussed. When planning for an underflight mission, the limited endurance of the aircraft (6 hr) and flight cost (2.7 K$/hr) must be considered. The advantage of the redundancy afforded by the several wave instruments is another important consideration.

  15. In situ measurements of Arctic atmospheric trace constituents from an aircraft

    NASA Technical Reports Server (NTRS)

    Reck, G. M.; Briehl, D.; Nyland, T. W.

    1977-01-01

    In situ measurements of the ambient concentrations of several atmospheric trace constituents were obtained using instruments installed on board the NASA Convair 990 aircraft at altitudes up to 12.5 kilometers over Alaska and the Arctic Ocean. Concentration data on ozone, carbon monoxide, water vapor, and particles larger than 0.5 micrometer in diameter were acquired.

  16. Ozonesonde and aircraft measurements in the tropical West Pacific from the CAST field campaign

    NASA Astrophysics Data System (ADS)

    Newton, Richard; Vaughan, Geraint; Ricketts, Hugo

    2015-04-01

    The Coordinated Airborne Studies in the Tropics (CAST) campaign comprised of ozonesonde launches and an aircraft campaign in the West Pacific in January-March 2014. Previous field campaigns in this region have highlighted an area to the east of Papua New Guinea and near the Solomon Islands as sources of deep convection and anomalously low ozone in the tropical tropopause layer (TTL). The CAST campaign provides a unique dataset of ozonesonde launches from Manus Island, Papua New Guinea, close to the hypothesized source region. CAST was performed in coordination with two sister campaigns, CONTRAST and ATTREX, bringing the FAAM BAe 146, NCAR Gulfstream V and NASA Global Hawk aircraft respectively to Guam. The aircraft campaign allowed an unprecedented comparison between ozonesondes and aircraft, which was used to verify the ozonesonde measurements and support the choice of background correction; this correction is of paramount importance in the tropics as the background constitutes half of the measured signal. The data obtained from the CAST ozonesondes suggest that the lowest ozone concentrations, at ~15 ppb, found in the tropical tropopause layer were accompanied by easterly winds from an area of deep convection, suggesting the air was lifted quickly from the marine boundary layer. The evidence from the CAST campaign suggests that the anomalously low near-zero ozone measured during previous campaigns in the tropical West Pacific is an artefact of the ozonesonde behaviour at low pressures (high altitude) - the low-ozone measurements can be recreated with the CAST ozonesondes if the background is not properly treated.

  17. Tropospheric sampling with aircraft

    SciTech Connect

    Daum, P.H.; Springston, S.R.

    1991-03-01

    Aircraft constitute a unique environment which places stringent requirements on the instruments used to measure the concentrations of atmospheric trace gases and aerosols. Some of these requirements such as minimization of size, weight, and power consumption are general; others are specific to individual techniques. This review presents the basic principles and considerations governing the deployment of trace gas and aerosol instrumentation on an aircraft. An overview of common instruments illustrates these points and provides guidelines for designing and using instruments on aircraft-based measurement programs.

  18. Aircraft cabin ozone measurements on B747-100 and B747-SP aircraft: Correlations with atmospheric ozone and ozone encounter statistics

    NASA Technical Reports Server (NTRS)

    Perkins, P. J.; Holdeman, J. D.; Gauntner, D. J.

    1978-01-01

    Simultaneous measurements of atmospheric (outside) ozone concentration and ozone levels in the cabin of the B747-100 and B747-SP airliners were made by NASA to evaluate the aircraft cabin ozone contamination problem. Instrumentation on these aircraft measured ozone from an outside probe and at one point in the cabin. Average ozone in the cabin of the B747-100 was 39 percent of the outside. Ozone in the cabin of the B747-SP measured 82 percent of the outside, before corrective measures. Procedures to reduce the ozone in this aircraft included changes in the cabin air circulation system, use of the high-temperature 15th stage compressor bleed, and charcoal filters in the inlet cabin air ducting, which as separate actions reduced the ozone to 58, 19 and 5 percent, respectively. The potential for the NASA instrumented B747 aircraft to encounter high levels of cabin ozone was derived from atmospheric oxone measurements on these aircraft. Encounter frequencies for two B747-100's were comparable even though the route structures were different. The B747-SP encountered high ozone than did the B747-100's.

  19. Development and Deployment of an Aerospace Recommended Practice (ARP) Compliant Measurement System for nvPM Certification Measurements of Aircraft Engines - Current Status.

    NASA Astrophysics Data System (ADS)

    Whitefield, P. D.; Hagen, D. E.; Lobo, P.; Miake-Lye, R. C.

    2015-12-01

    The Society of Automotive Engineers (SAE) Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter (nvPM) from aircraft engines (SAE 2013). The system is designed to operate in parallel with existing International Civil Aviation Organization (ICAO) Annex 16 compliant combustion gas sampling systems used for emissions certification from aircraft engines captured by conventional (Annex 16) gas sampling rakes (ICAO, 2008). The SAE E-31 committee is also working to ballot an Aerospace Recommended Practice (ARP) that will provide the methodology and system specification to measure nvPM from aircraft engines. The ARP is currently in preparation and is expected to be ready for ballot in 2015. A prototype AIR-compliant nvPM measurement system - The North American Reference System (NARS) has been built and evaluated at the MSTCOE under the joint sponsorship of the FAA, EPA and Transport Canada. It has been used to validate the performance characteristics of OEM AIR-compliant systems and is being used in engine certification type testing at OEM facilities to obtain data from a set of representative engines in the fleet. The data collected during these tests will be used by ICAO/CAEP/WG3/PMTG to develop a metric on which on the regulation for nvPM emissions will be based. This paper will review the salient features of the NARS including: (1) emissions sample transport from probe tip to the key diagnostic tools, (2) the mass and number-based diagnostic tools for nvPM mass and number concentration measurement and (3) methods employed to assess the extent of nvPM loss throughout the sampling system. This paper will conclude with a discussion of the recent results from inter-comparison studies conducted with other US - based systems that gives credence to the ARP's readiness for ballot.

  20. Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure

    NASA Astrophysics Data System (ADS)

    Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

    2013-01-01

    An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The

  1. Measurements and simulations of the radiation exposure to aircraft crew workplaces due to cosmic radiation in the atmosphere.

    PubMed

    Beck, P; Latocha, M; Dorman, L; Pelliccioni, M; Rollet, S

    2007-01-01

    As required by the European Directive 96/29/Euratom, radiation exposure due to natural ionizing radiation has to be taken into account at workplaces if the effective dose could become more than 1 mSv per year. An example of workers concerned by this directive is aircraft crew due to cosmic radiation exposure in the atmosphere. Extensive measurement campaigns on board aircrafts have been carried out to assess ambient dose equivalent. A consortium of European dosimetry institutes within EURADOS WG5 summarized experimental data and results of calculations, together with detailed descriptions of the methods for measurements and calculations. The radiation protection quantity of interest is the effective dose, E (ISO). The comparison of results by measurements and calculations is done in terms of the operational quantity ambient dose equivalent, H(10). This paper gives an overview of the EURADOS Aircraft Crew In-Flight Database and it presents a new empirical model describing fitting functions for this data. Furthermore, it describes numerical simulations performed with the Monte Carlo code FLUKA-2005 using an updated version of the cosmic radiation primary spectra. The ratio between ambient dose equivalent and effective dose at commercial flight altitudes, calculated with FLUKA-2005, is discussed. Finally, it presents the aviation dosimetry model AVIDOS based on FLUKA-2005 simulations for routine dose assessment. The code has been developed by Austrian Research Centers (ARC) for the public usage (http://avidos.healthphysics.at).

  2. A STUDY OF EXTRACTIVE AND REMOTE-SENSING SAMPLING AND MEASUREMENT OF EMISSIONS FROM MILITARY AIRCRAFT ENGINES

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.

    2010-01-01

    Aircraft emissions contribute to the increased atmospheric burden of particulate matter (e.g., black carbon and secondary organic compounds) that plays a role in air quality, contrail formation and climate change. Sampling and measurement of modern aircraft emissions at the engine exhaust plane (EEP) for to engine and fuel certification remains a daunting task, no agency-certified method is available for the task. In this paper we summarize the results of a recent study that was devoted to investigate both extractive and optical remote-sensing (ORS) technologies in sampling and measurement of gaseous and particulate matter (PM) emitted by a number of military aircraft engines operated with JP-8 and a Fischer-Tropsch (FT) fuel at various engine conditions. These engines include cargo, bomber, and helicopter types of military aircraft that consumes 70-80% of the military aviation fuel each year. The emission indices of selected pollutants are discussed as these data may be of interest for atmospheric modeling and for design of air quality control strategies around the airports and military bases. It was found that non-volatile particles in the engine emissions were all in the ultrafine range. The mean diameter of particles increased as the engine power increased; the mode diameters were in the 20nm range for the low power condition of a new helicopter engine to 80nm for the high power condition of a newly maintained bomber engine. Elemental analysis indicated little metals were present on particles in the exhaust, while most of the materials on the exhaust particles were based on carbon and sulfate. Carbon monoxide, carbon dioxide, nitrogen oxide, sulfur dioxide, formaldehyde, ethylene, acetylene, propylene, and alkanes were detected using both technologies. The last five species (in the air toxics category) were most noticeable only under the low engine power. The emission indices calculated based on the ORS data were however observed to differ significantly (up to

  3. Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2011-01-01

    An emerging approach in the field of aircraft engine controls and system health management is the inclusion of real-time, onboard models for the inflight estimation of engine performance variations. This technology, typically based on Kalman-filter concepts, enables the estimation of unmeasured engine performance parameters that can be directly utilized by controls, prognostics, and health-management applications. A challenge that complicates this practice is the fact that an aircraft engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. Through Kalman-filter-based estimation techniques, the level of engine performance degradation can be estimated, given that there are at least as many sensors as health parameters to be estimated. However, in an aircraft engine, the number of sensors available is typically less than the number of health parameters, presenting an under-determined estimation problem. A common approach to address this shortcoming is to estimate a subset of the health parameters, referred to as model tuning parameters. The problem/objective is to optimally select the model tuning parameters to minimize Kalman-filterbased estimation error. A tuner selection technique has been developed that specifically addresses the under-determined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine that seeks to minimize the theoretical mean-squared estimation error of the Kalman filter. This approach can significantly reduce the error in onboard aircraft engine parameter estimation

  4. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2016-02-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

  5. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2015-10-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light emitting diodes (LEDs) and a grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high power LEDs with electronic on/off modulation, state-of-the-art cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350 and 80 pptv in 5 s. The accuracy is 5.8, 9.0 and 5.0 % limited mainly by the available absorption cross sections.

  6. Aircraft Measurements Of Refractive And Clear Air Turbulence: Spectra, Budgets, And The Prediction Problem

    NASA Astrophysics Data System (ADS)

    Cote, O.; Dobosy, R.; Roadcap, J.; Crawford, T.; Hacker, J.

    Four turbulence measurement campaigns were performed in the winter sub-tropical jet streams of south coastal Japan and Australia during 1998-2001 with the objective to capture the dynamics of severe refractive and clear air turbulence events. The aircraft used was the GROB 520T EGRETT, which is owned and operated by Airborne Research Australia a unit of Flinders University of South Australia. Severe turbulence events are difficult to forecast and measure but are of critical importance to commercial air safety (NASA -FAA) and the High-Energy Laser (HEL) propagation disturbances. Measurements have shown that weak turbulence/severe turbulence events are associated with anisotropy/isotropy of the turbulent velocity spectra/structure parameters. Strong turbulence events are associated with Froude number that are near unity; weak turbulence with Froude numbers 1. The role that fluctuating velocity-pressure gradient correlation in maintaining strong turbulence, the limited success of Richardson number as a predictor, and limitations of diagnostic prediction schemes based on mesoscale model output will be considered.

  7. Effective density measurements of fresh particulate matter emitted by an aircraft engine

    NASA Astrophysics Data System (ADS)

    Abegglen, Manuel; Durdina, Lukas; Mensah, Amewu; Brem, Benjamin; Corbin, Joel; Rindlisbacher, Theo; Wang, Jing; Lohmann, Ulrike; Sierau, Berko

    2014-05-01

    organic aerosols. The soot masses/densities were determined using a DMA-CPMA system as described in the following. The freshly generated soot particles were first charge equilibrated to account for multiple charging and selected according to their mobility size (dm) by a DMA. The monodisperse flow then entered the CPMA which measured the corresponding mass. A condensation particle counter counted the particle number concentration. The effective density (ρeff) can be derived using the fractal relationship between mass and dm and the definition of the effective density. Additionally, we investigated four different laboratory-generated soot types at ETHZ. In detail, a Combustion Aerosol Standard burner ((1) fuel-rich and (2) fuel-lean), a (3) PALAS GFG aerosol generator and (4) carbon black (Cabot Regal Black) from an atomizer, were used. The corresponding results are compared to the aircraft engine exhaust measurements. Results The size, mass, effective density distributions, and the corresponding mobility based fractal dimensions (Dfm) from fresh soot particles emitted by a common aircraft engine and from four laboratory generated soot types were analysed. Dfm is used to describe aggregate particles. It relates the number of primary particles to dm. In general, the effective density decreases with increasing mobility diameter and depends on engine thrust.

  8. An intercomparison of aircraft instrumentation for tropospheric measurements of carbonyl sulfide, hydrogen sulfide, and carbon disulfide

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Davis, Douglas D.; Thornton, Donald C.; Johnson, James E.; Bandy, Alan R.; Saltzman, Eric S.; Andreae, Meinrat O.; Barrick, John D.

    1993-01-01

    This paper reports results of NASA's Chemical Instrumentation and Test Evaluation (CITE 3) during which airborne measurements for carbonyl sulfide (COS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were intercompared. Instrumentation included a gas chromatograph using flame photometric detection (COS, H2S, and CS2), a gas chromatograph using mass spectrometric detection (COS) and CS2), a gas chromatograph using fluorination and subsequent SF6 detection via electron capture (COS and CS2), and the Natusch technique (H2S). The measurements were made over the Atlantic Ocean east of North and South America during flights from NASA's Wallops Flight Center, Virginia, and Natal, Brazil, in August/September 1989. Most of the intercomparisons for H2S and CS2 were at mixing ratios less than 25 pptv and less than 10 pptv, respectively, with a maximum mixing ratio of about 100 pptv and 50 pptv, respectively. Carbonyl sulfide intercomparisons were at mixing ratios between 400 and 600 pptv. Measurements were intercompared from data bases constructed from time periods of simultaneous or overlapping measurements. Agreement among the COS techniques averaged about 5%, and individual measurements were generally within 10%. For H2S and at mixing ratio greater than 25 pptv, the instruments agreed on average to about 15%. At mixing ratios less than 25 pptv the agreement was about 5 pptv. For CS2 (mixing ratios less than 50 pptv), two techniques agreed on average to about 4 pptv, and the third exhibited a bias (relative to the other two) that varied in the range of 3-7 pptv. CS2 mixing ratios over the ocean east of Natal as measured by the gas chromatograph-mass spectrometer technique were only a few pptv and were below the detection limits of the other two techniques. The CITE 3 data are used to estimate the current uncertainty associated with aircraft measurements of COS, H2S, and CS2 in the remote troposphere.

  9. Should helicopter noise be measured differently from other aircraft noise? A review of the psychoacoustic literature

    NASA Technical Reports Server (NTRS)

    Molino, J. A.

    1982-01-01

    A review of 34 studies indicates that several factors or variables might be important in providing a psychoacoustic foundation for measurements of the noise from helicopters. These factors are phase relations, tail rotor noise, repetition rate, crest level, and generic differences between conventional aircraft and helicopters. Particular attention was given to the impulsive noise known as blade slap. Analysis of the evidence for and against each factor reveals that, for the present state of scientific knowledge, none of these factors should be regarded as the basis for a significant noise measurement correction due to impulsive blade slap. The current method of measuring effective perceived noise level for conventional aircraft appears to be adequate for measuring helicopter noise as well.

  10. Absorption of Solar Radiation by the Cloudy Atmosphere Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.; Cess, Robert D.; Zhang, Minghua; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Vitko, John, Jr.

    1997-01-01

    As part of the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE), we have obtained and analyzed measurements made from collocated aircraft of the absorption of solar radiation within the atmospheric column between the two aircraft. The measurements were taken during October 1995 at the ARM site in Oklahoma. Relative to a theoretical radiative transfer model, we find no evidence for excess solar absorption in the clear atmosphere and significant evidence for its existence in the cloudy atmosphere. This excess cloud solar absorption appears to occur in both visible (0.224-0.68 microns) and near-infrared (0.68-3.30 microns) spectral regions, although not at 0.5 microns for the visible contribution, and it is shown to be true absorption rather than an artifact of sampling errors caused by measuring three-dimensional clouds.

  11. New technique for the direct measurement of core noise from aircraft engines. [YF 102 turbofan engine

    NASA Technical Reports Server (NTRS)

    Krejsa, E. A.

    1981-01-01

    The core noise levels from gas turbine aircraft engines were measured using a technique which requires that fluctuating pressures be measured in the far field and at two locations within the engine core. The cross spectra of these measurements are used to determine the levels of the far-field noise that propagated from the engine vore. The technique makes it possible to measure core noise levels even when other noise sources dominate. The technique was applied to signals measured from an Avco Lycoming YF102 turbofan engine. Core noise levels as a function of frequency and radiation angle were measured and are presented over a range of power settings.

  12. Accurate Measurements of Aircraft Engine Soot Emissions Using a CAPS PMssa Monitor

    NASA Astrophysics Data System (ADS)

    Onasch, Timothy; Thompson, Kevin; Renbaum-Wolff, Lindsay; Smallwood, Greg; Make-Lye, Richard; Freedman, Andrew

    2016-04-01

    We present results of aircraft engine soot emissions measurements during the VARIAnT2 campaign using CAPS PMssa monitors. VARIAnT2, an aircraft engine non-volatile particulate matter (nvPM) emissions field campaign, was focused on understanding the variability in nvPM mass measurements using different measurement techniques and accounting for possible nvPM sampling system losses. The CAPS PMssa monitor accurately measures both the optical extinction and scattering (and thus single scattering albedo and absorption) of an extracted sample using the same sample volume for both measurements with a time resolution of 1 second and sensitivity of better than 1 Mm-1. Absorption is obtained by subtracting the scattering signal from the total extinction. Given that the single scattering albedo of the particulates emitted from the aircraft engine measured at both 630 and 660 nm was on the order of 0.1, any inaccuracy in the scattering measurement has little impact on the accuracy of the ddetermined absorption coefficient. The absorption is converted into nvPM mass using a documented Mass Absorption Coefficient (MAC). Results of soot emission indices (mass soot emitted per mass of fuel consumed) for a turbojet engine as a function of engine power will be presented and compared to results obtained using an EC/OC monitor.

  13. Combustion noise from gas turbine aircraft engines measurement of far-field levels

    NASA Technical Reports Server (NTRS)

    Krejsa, Eugene A.

    1987-01-01

    Combustion noise can be a significant contributor to total aircraft noise. Measurement of combustion noise is made difficult by the fact that both jet noise and combustion noise exhibit broadband spectra and peak in the same frequency range. Since in-flight reduction of jet noise is greater than that of combustion noise, the latter can be a major contributor to the in-flight noise of an aircraft but will be less evident, and more difficult to measure, under static conditions. Several methods for measuring the far-field combustion noise of aircraft engines are discussed in this paper. These methods make it possible to measure combustion noise levels even in situations where other noise sources, such as jet noise, dominate. Measured far-field combustion noise levels for several turbofan engines are presented. These levels were obtained using a method referred to as three-signal coherence, requiring that fluctuating pressures be measured at two locations within the engine core in addition to the far-field noise measurement. Cross-spectra are used to separate the far-field combustion noise from far-field noise due to other sources. Spectra and directivities are presented. Comparisons with existing combustion noise predictions are made.

  14. An Aircraft And Radar Based Analysis Of Cloud And Precipitation Microphysics In Mid-Latitude Continental Clouds

    NASA Astrophysics Data System (ADS)

    Mishra, S.; Kumjian, M.; Bansemer, A.; Giangrande, S. E.; Ryzhkov, A.; Toto, T.

    2014-12-01

    An observational analysis of precipitation microphysics was conducted using data obtained during the Midlatitude Continental Convective Clouds Experiment (MC3E) that took place around the Atmospheric Radiation Measurement (ARM) site in Lamont, Oklahoma from April 22- June 6, 2011. MC3E was a collaborative campaign led by the National Aeronautic and Space Administration's (NASA's) Global Precipitation Measurement (GPM) mission and the U.S. Department of Energy ARM program. MC3E provided a unique opportunity to compare in-situ data from aircraft based microphysical probes with data from polarimetric radars in the radar bright band region or melting layer. One of the primary objectives of this study was to understand how riming and aggregation affect polarimetric signatures. In depth case study analysis of cloud and precipitation microphysics was performed for two specific cases, April 27th, 2011 (A27) and May 20th, 2011 (M20). Both these cases provided coincident aircraft and radar data in extensive stratiform cloud regions. Measurements from the University of North Dakota (UND) Citation aircraft and polarimetric data from the ARM CSAPR data reveal interesting details of cloud scale processes. Observations based on data from cloud probes (2DC, CIP and HVPS) along with in-situ observations of environmental variables provide remarkable details of particle growth and cloud dynamics for both case studies. For the A27 case study, UND aircraft measurements from two successive spiral profiles through the stratiform cloud region showed a transition from a riming dominated region to an aggregation dominated region. This is supported by polarimetric data from the C-Band ARM Precipitation Radar (CSAPR ). An extensive region of trailing stratiform precipitation was sampled in the M20 case study, where the aggregation, melting, and evaporation processes were measured in detail with the in-situ microphysical instruments. Latest findings from MC3E based on this combined aircraft

  15. Measurements of Nucleation-Mode Particle Size Distributions in Aircraft Plumes during SULFUR 6

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.; Bradford, Deborah G.

    1999-01-01

    This report summarizes the participation of the University of Denver in an airborne measurement program, SULFUR 6, which was undertaken in late September and early October of 1998 by the Deutsches Zentrum fur Luft und Raumfahrt (DLR). Scientific findings from two papers that have been published or accepted and from one manuscript that is in preparation are presented. The SULFUR 6 experiment was designed to investigate the emissions from subsonic aircraft to constrain calculations of possible atmospheric chemical and climatic effects. The University of Denver effort contributed toward the following SULFUR 6 goals: (1) To investigate the relationship between fuel sulfur content (FSC--mass of sulfur per mass of fuel) and particle number and mass emission index (El--quantity emitted per kg of fuel burned); (2) To provide upper and lower limits for the mass conversion efficiency (nu) of fuel sulfur to gaseous and particulate sulfuric acid; (3) To constrain models of volatile particle nucleation and growth by measuring the particle size distribution between 3 and 100 nm at aircraft plume ages ranging from 10(exp -1) to 10(exp 3) s; (4) To determine microphysical and optical properties and bulk chemical composition of soot particles in aircraft exhaust; and (5) To investigate the differences in particle properties between aircraft plumes in contrail and non-contrail situations. The experiment focused on emissions from the ATTAS research aircraft (a well characterized, but older technology turbojet) and from an in-service Boeing 737-300 aircraft provided by Lufthansa, with modem, high-bypass turbofan engines. Measurements were made from the DLR Dassault Falcon 900 aircraft, a modified business jet. The Atmospheric Effects of Aviation Program (AEAP) provided funding to operate an instrument, the nucleation-mode aerosol size spectrometer (N-MASS), during the SULFUR 6 campaign and to analyze the data. The N-MASS was developed at the University of Denver with the support of

  16. Lidar Measurements of Methane and Applications for Aircraft and Spacecraft

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Abshire, James; Li, Steve; Wu, Stewart; Krainak, Michael; Sun, Xiaoli

    2010-01-01

    Atmospheric methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but observations since 2007 show that levels may be increasing. This trend may be caused by increased fossil fuel production, rice farming, livestock and landfills, but the underlying causes are quite uncertain. One hypothesis is that reservoirs of carbon trapped in the permafrost regions of northern Canada, Europe, and Siberia thaw as global temperatures rise and are releasing increasing amounts of methane. Another hypothesis points to increased production of methane by microbes as the permafrost warms. Currently most observations of greenhouse gases are limited to in-situ (surface and tower sites) and limited airborne in-situ measurements. Space column density measurements are starting to become available from the GOSAT mission. Although methane survives for a shorter time in the atmosphere than CO2, its impact on climate change per molecule is about 23 times than that of CO2. Accurate global observations of several greenhouse gases, including methane, are urgently needed in order to better understand climate change processes and to reduce the uncertainty in the carbon budget. Differential absorption lidar is a well-established technique to measure atmospheric gases, and methane has optical absorption bands near 1.65,2.2,3.4 and 7.8 micron. The near infrared overtones lines of CH4 near 1650 nm are relatively free of interference from other species. There are absorption lines near 1651 nm which are both temperature insensitive and have line strengths well suited for lidar measurements. We have developed a laser and demonstrated lidar measurements of CH4 using lines in this band. Our laser uses a narrow linewidth 1064 nm laser pulse passing through a nonlinear crystal. We generate the tunable laser signals near 1651 nm by using the optical parametric amplification (OPA) process. Inside the crystal the 1064 nm beam overlaps with an injection seed

  17. A Comparison of Modeled Pollutant Profiles With MOZAIC Aircraft Measurements

    EPA Science Inventory

    In this study, we use measurements performed under the MOZAIC program to evaluate vertical profiles of meteorological parameters, CO, and ozone that were simulated for the year 2006 with several versions of the WRF/CMAQ modeling system. Model updates, including WRF nudging strate...

  18. A Framework for Preliminary Design of Aircraft Structures Based on Process Information. Part 1

    NASA Technical Reports Server (NTRS)

    Rais-Rohani, Masoud

    1998-01-01

    This report discusses the general framework and development of a computational tool for preliminary design of aircraft structures based on process information. The described methodology is suitable for multidisciplinary design optimization (MDO) activities associated with integrated product and process development (IPPD). The framework consists of three parts: (1) product and process definitions; (2) engineering synthesis, and (3) optimization. The product and process definitions are part of input information provided by the design team. The backbone of the system is its ability to analyze a given structural design for performance as well as manufacturability and cost assessment. The system uses a database on material systems and manufacturing processes. Based on the identified set of design variables and an objective function, the system is capable of performing optimization subject to manufacturability, cost, and performance constraints. The accuracy of the manufacturability measures and cost models discussed here depend largely on the available data on specific methods of manufacture and assembly and associated labor requirements. As such, our focus in this research has been on the methodology itself and not so much on its accurate implementation in an industrial setting. A three-tier approach is presented for an IPPD-MDO based design of aircraft structures. The variable-complexity cost estimation methodology and an approach for integrating manufacturing cost assessment into design process are also discussed. This report is presented in two parts. In the first part, the design methodology is presented, and the computational design tool is described. In the second part, a prototype model of the preliminary design Tool for Aircraft Structures based on Process Information (TASPI) is described. Part two also contains an example problem that applies the methodology described here for evaluation of six different design concepts for a wing spar.

  19. Comparison of Pandora spectrometer NO2 measurements to aircraft, satellite, and ground measurements during the DISCOVER-AQ Texas campaign

    NASA Astrophysics Data System (ADS)

    Judd, L.; Lefer, B. L.; Herman, J. R.; Abuhassan, N.; Cede, A.; Cohen, R. C.; Janz, S. J.; Ren, X.; Luke, W. T.; Long, R.

    2014-12-01

    Pandora spectrometer measurements are compared to other remotely sensed and in-situ NO2 measurements in the Houston, TX region during the third deployment of the DISCOVER-AQ campaign in September 2013. The network of freeways, petrochemical facilities, and related industries contribute to an ongoing pollution problem in the Houston region with the direct emissions of NOx and VOCs producing secondary pollutants such as ozone and PM2.5. The goal of this work is to determine how the Pandora spectrometer column measurements of NO2 compare to in-situ derived and other remotely sensed columns, as well as with ground measurements during this deployment of DISCOVER-AQ. UC Berkeley's LIF measurements of NO2 aboard the NASA P-3B at each spiral site are used to create the aircraft derived profiles of NO2. The aircraft measured profiles include upwind, source, and receptor sites in the region, three times a day, at eight different locations. In addition, we investigate how the NO2 profile shape changes both spatially and temporally, with a focus on the difference between the boundary layer and free troposphere distributions. Pandora measurements are also compared to column measurements from the Ozone Monitoring Instrument and ACAM aboard the B200 aircraft. Where available, surface measurements are included to supplement aircraft profiles and are correlated to the Pandora column measurements to determine the relationship between the total NO2 column and ground concentrations. Understanding of how these measurements compare spatially and temporally will aid both future Pandora deployments and satellite retrievals.

  20. Comparison of Profiling Microwave Radiometer, Aircraft, and Radiosonde Measurements From the Alliance Icing Research Study (AIRS)

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.

    2001-01-01

    Measurements from a profiling microwave radiometer are compared to measurements from a research aircraft and radiosondes. Data compared is temperature, water vapor, and liquid water profiles. Data was gathered at the Alliance Icing Research Study (AIRS) at Mirabel Airport outside Montreal, Canada during December 1999 and January 2000. All radiometer measurements were found to lose accuracy when the radome was wet. When the radome was not wetted, the radiometer was seen to indicate an inverted distribution of liquid water within a cloud. When the radiometer measurements were made at 15 deg. instead of the standard zenith, the measurements were less accurate.

  1. Direct measurement of transmission loss of aircraft structures using the acoustic intensity approach

    NASA Technical Reports Server (NTRS)

    Wang, Y. S.; Crocker, M. J.

    1982-01-01

    A measurement technique is developed in order to obtain the sound transmission loss of an aircraft fuselage which obviates the need for the two-room transmission suite. The sound transmission paths were determined in tests on a light aircraft fuselage using a two-microphone acoustic intensity method for measuring the acoustic intensity transmitted to the interior when the fuselage was exposed to an external random incidence sound-field. The intensity transmitted through different sections of the fuselage can be estimated accurately using this new technique. Results of these tests show that the plexiglass window is the major transmission path in the high frequency range. In addition, the transmission losses through a single and a double layer window were predicted theoretically by using the Statistical Energy Analysis Model. Very good agreement is found between the predictions and the measurements.

  2. A solid state converter for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1972-01-01

    The problems inherent in present systems of instrumentation for measuring aircraft noise and sonic boom include limited frequency response, expensive connecting cables, sensitivity to cable length and type, high sensitivity to environmental conditions, and additional limitations of individual system components. Furthermore, differing requirements have resulted in the use of two different systems for aircraft noise and sonic boom measurements respectively. To alleviate these difficulties a unified system of instrumentation suitable for both types of measurements was developed. The system features a new solid state converter connected to a zero drive amplifier. The system was found insensitive to cable length and type up to at least 1000 ft and requires no impedance matching networks. The converter itself has flat frequency response from dc to 28 kHz (- 3 db), dynamic range of 72 db, and noise floor of 50 db in the band 22.4 Hz to 22.4 kHz.

  3. Measurements of wave-cloud microphysical properties with two new aircraft probes

    NASA Astrophysics Data System (ADS)

    Gerber, H.; Twohy, Cynthia H.; Gandrud, Bruce; Heymsfield, Andrew J.; McFarquhar, Greg M.; DeMott, Paul J.; Rogers, David C.

    Measurements of ice water content (IWC) and mean ice-crystal size and concentration made by two in-situ probes, CVI and PVM, were compared on the DC-8 aircraft during SUCCESS flights in orographic ice clouds. The comparison of IWC in these wave clouds, that formed at temperatures of about -38 °C on April 30 and -62 °C on May 2, 1996, showed good agreement. The comparison of ice crystal concentrations agreed better for the April-30 clouds than for the May-2 clouds; and the effective radius compared for both probes and for remote retrievals from aircraft and satellite for a segment of the Berthoud wave cloud (May 2) agreed within 30%. The measured parameters of the ice crystals were similar to earlier measurements and recent modeling of cold wave clouds.

  4. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-11-01

    Because of the high travel speed, the complex flow dynamics around an aircraft, and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore, these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realised with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 to 800 hPa, and a water vapour concentration range of more than 3 orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements shows an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2 and 5.1% during in-flight operation on the HALO airplane. Under

  5. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-05-01

    Because of the high travel speed, the complex flow dynamics around an aircraft and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realized with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 hPa to 800 hPa, and a water vapour concentration range of more than three orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements show an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2% and 5.1% during in flight operation on the HALO airplane

  6. Aircraft wind measurement considering lift-induced upwash

    NASA Astrophysics Data System (ADS)

    Crawford, Timothy L.; Dobosy, Ronald J.; Dumas, Edward J.

    1996-07-01

    Flow distortion is a universal consideration in the measurement of wind. Usually the distortion results from deflection of the flow by the support. Instruments mounted on airplanes, however, experience an additional deflection associated with lift, which changes rapidly and continuously during flight. In front of the airplane, this deflection appears as upwash. Characteristic upwash contamination ranges from 0.5 to 2.5 m s-1, depending on wing loading, flight speed, and forward distance from the wing to the measurement location. On pressure-radome installations the distance from the wing is usually small and the potential for upwash contamination large. Sensors mounted at the end of long probes attached to smaller airplanes with light wing loading are less susceptible to upwash contamination. Since wing loading also depends on the local vertical wind velocity the upwash velocity is directly correlated with vertical wind velocity. Generally, empirical corrections are derived from flight tests. We develop a simple method from principles of aerodynamics which explains these corrections in terms of upwash. The applicability of our approach to moderate upwash is demonstrated with data collected from the NOAA Long-EZ research airplane. More severe upwash conditions require a more sophisticated correction beyond the scope of this paper, but basically derived from the same principles.

  7. Improving the Aircraft Design Process Using Web-Based Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.; Follen, Gregory J. (Technical Monitor)

    2000-01-01

    Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

  8. Improving the Aircraft Design Process Using Web-based Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.

    2003-01-01

    Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and muitifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

  9. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  10. An optimization method for condition based maintenance of aircraft fleet considering prognostics uncertainty.

    PubMed

    Feng, Qiang; Chen, Yiran; Sun, Bo; Li, Songjie

    2014-01-01

    An optimization method for condition based maintenance (CBM) of aircraft fleet considering prognostics uncertainty is proposed. The CBM and dispatch process of aircraft fleet is analyzed first, and the alternative strategy sets for single aircraft are given. Then, the optimization problem of fleet CBM with lower maintenance cost and dispatch risk is translated to the combinatorial optimization problem of single aircraft strategy. Remain useful life (RUL) distribution of the key line replaceable Module (LRM) has been transformed into the failure probability of the aircraft and the fleet health status matrix is established. And the calculation method of the costs and risks for mission based on health status matrix and maintenance matrix is given. Further, an optimization method for fleet dispatch and CBM under acceptable risk is proposed based on an improved genetic algorithm. Finally, a fleet of 10 aircrafts is studied to verify the proposed method. The results shows that it could realize optimization and control of the aircraft fleet oriented to mission success.

  11. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  12. Evaluating and Constraining Ice Cloud Parameterizations in CAM5 using Aircraft Measurements from the SPARTICUS Campaign

    SciTech Connect

    Zhang, Kai; Liu, Xiaohong; Wang, Minghuai; Comstock, Jennifer M.; Mitchell, David; Mishra, Subhashree; Mace, Gerald G.

    2013-05-14

    This study uses aircraft measurements of relative humidity and ice crystal size distribution collected in synoptic cirrus during the SPARTICUS (Small PARTicles In CirrUS) field campaign to evaluate and constrain ice cloud parameterizations in the Community Atmosphere Model version 5. The probability density function (PDF) of ice crystal number concentration (Ni) derived from high frequency (1 Hz) measurements features a strong dependence on ambient temperature. As temperature decreases from -35°C to -62°C, the peak in the PDF shifts from 10-20 L-1 to 200-1000 L-1, while the ice crystal number concentration shows a factor of 6-7 increase. Model simulations are performed with two different insitu ice nucleation schemes. One of the schemes can reproduce a clear increase of Ni with decreasing temperature, by using either an observation based ice nuclei spectrum or a classical theory based spectrum with a relatively low (5%-10%) maximum freezing ratio for dust aerosols. The simulation with the other scheme, which assumes a high maximum freezing ratio (100%), shows much weaker temperature dependence of Ni. Simulations are also performed to test empirical parameters related to water vapor deposition and the auto-conversion of ice crystals to snow. Results show that a value between 0.05 and 0.1 for the water vapor deposition coefficient and 250 um for the critical ice crystal size can produce good agreements between model simulation and the SPARTICUS measurements in terms of ice crystal number concentration and effective radius. The climate impact of perturbing these parameters is also discussed.

  13. Radiometric gains of satellite sensors of reflected solar radiation - Results from NASA ER-2 aircraft measurements

    NASA Technical Reports Server (NTRS)

    Abel, Peter; Galimore, Reginald; Cooper, John

    1992-01-01

    A method for using congruent aircraft-satellite observations to calibrate a satellite sensor is presented. A calibrated spectroradiometer at an altitude of 19 km above White Sands, NM, is oriented to view White Sands at the satellite overpass time along the same view vector as the satellite sensor. Collected data are transformed into corresponding estimates of sensor band radiance at the satellite (derived from the aircraft measurements), and average count (from the sensor measurements). These are both averaged across the footprint of the spectroradiometer. Results are presented for the evolution of NOAA-11 Advanced Very High Resolution Radiometer (AVHRR) (Bands 1 and 2) gain between November 1988 and October 1990, and for GOES-6 and GOES-7 VISSR/VAS visible bands during the same period. Estimates of uncertainty in the results are presented, as well as ideas for their reduction in future flights.

  14. Measurements of Long-Lived Trace Gases from Commercial Aircraft Platforms: Development of Instrumentation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The upper troposphere (6-12 km altitude) is a poorly understood and highly vulnerable region of the atmosphere. It is important because many trace species, including ozone, have their greatest impact as greenhouse (infrared-absorbing) gases in this region. The addition of relatively small amounts of anthropogenic chemicals, such as nitrogen oxides, can have a dramatic effect on the abundance of ozone. Some of these pollutants are deposited directly, e.g., by aircraft, while others are transported in. The primary goal of this project was to measure several chemical compounds in the upper troposphere that will help us to understand how air is to transported to that part of the atmosphere; that is, does it come down from the stratosphere, does it rise from the surface via convection, and so on. To obtain adequate sampling to accomplish this goal, we proposed to make measurements from revenue aircraft during normal flight operations.

  15. A new measurement method for separating airborne and structureborne noise radiated by aircraft type panels

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1982-01-01

    The theoretical basis for and experimental validation of a measurement method for separating airborne and structure borne noise radiated by aircraft type panels are presented. An extension of the two microphone, cross spectral, acoustic intensity method combined with existing theory of sound radiation of thin shell structures of various designs, is restricted to the frequency range below the coincidence frequency of the structure. Consequently, the method lends itself to low frequency noise problems such as propeller harmonics. Both an aluminum sheet and two built up aircraft panel designs (two aluminum panels with frames and stringers) with and without added damping were measured. Results indicate that the method is quick, reliable, inexpensive, and can be applied to thin shell structures of various designs.

  16. Downscaling of Aircraft-, Landsat-, and MODIS-based Land Surface Temperature Images with Support Vector Machines

    NASA Astrophysics Data System (ADS)

    Ha, W.; Gowda, P. H.; Oommen, T.; Howell, T. A.; Hernandez, J. E.

    2010-12-01

    High spatial resolution Land Surface Temperature (LST) images are required to estimate evapotranspiration (ET) at a field scale for irrigation scheduling purposes. Satellite sensors such as Landsat 5 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) can offer images at several spectral bandwidths including visible, near-infrared (NIR), shortwave-infrared, and thermal-infrared (TIR). The TIR images usually have coarser spatial resolutions than those from non-thermal infrared bands. Due to this technical constraint of the satellite sensors on these platforms, image downscaling has been proposed in the field of ET remote sensing. This paper explores the potential of the Support Vector Machines (SVM) to perform downscaling of LST images derived from aircraft (4 m spatial resolution), TM (120 m), and MODIS (1000 m) using normalized difference vegetation index images derived from simultaneously acquired high resolution visible and NIR data (1 m for aircraft, 30 m for TM, and 250 m for MODIS). The SVM is a new generation machine learning algorithm that has found a wide application in the field of pattern recognition and time series analysis. The SVM would be ideally suited for downscaling problems due to its generalization ability in capturing non-linear regression relationship between the predictand and the multiple predictors. Remote sensing data acquired over the Texas High Plains during the 2008 summer growing season will be used in this study. Accuracy assessment of the downscaled 1, 30, and 250 m LST images will be made by comparing them with LST data measured with infrared thermometers at a small spatial scale, upscaled 30 m aircraft-based LST images, and upscaled 250 m TM-based LST images, respectively.

  17. An intercomparison of aircraft instrumentation for tropospheric measurements of sulfur dioxide

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Davis, Douglas D.; Beltz, Nobert; Bandy, Alan R.; Ferek, Ronald J.; Thornton, Donald C.

    1993-01-01

    As part of the NASA Tropospheric Chemistry Program, a series of field intercomparisons have been conducted to evaluate the state-of-the art for measuring key tropospheric species. One of the objectives of the third intercomparison campaign in this series, Chemical Instrumentation Test and Evaluation 3 (CITE 3), was to evaluate instrumentation for making reliable tropospheric aircraft measurements of sulfur dioxide, dimethyl sulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide. This paper reports the results of the intercomparisons of five sulfur dioxide measurement methods ranging from filter techniques, in which samples collected in flight are returned to the laboratory for analyses (chemiluminescent or ion chromatographic), to near real-time, in-flight measurements via gas chromatographic, mass spectrometric, and chemiluminescent techniques. All techniques showed some tendency to track sizeable changes in ambient SO2 such as those associated with altitude changes. For SO2 mixing ratios in the range of 200 pptv to a few ppbv, agreement among the techniques varies from about 30% to several orders of magnitude, depending upon the pair of measurements intercompared. For SO2 mixing ratios less than 200 pptv, measurements from the techniques are uncorrelated. In general, observed differences in the measurement of standards do not account for the flight results. The CITE 3 results do not unambiguously identify one or more of the measurement techniques as providing valid or invalid SO2 measurements, but identify the range of 'potential' uncertainty in SO2 measurements reported by currently available instrumentation and as measured under realistic aircraft environments.

  18. REAL-TIME AND INTEGRATED MEASUREMENT OF POTENTIAL HUMAN EXPOSURE TO PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM AIRCRAFT EXHAUST

    EPA Science Inventory

    Real-time monitors and low-volume air samplers were used to measure the potential human exposure to airborne polycyclic aromatic hydrocarbon (PAH) concentrations during various flight-related and ground-support activities of C-130H aircraft at an Air National Guard base. Three...

  19. Aircraft maintenance. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Zollars, G. F.

    1980-01-01

    These citations from the international literature concern various aspects of aircraft maintenance. Both military and civil aviation experience are included. Articles cited concern airline operations, engine and avionics reliability, the use of automatic test equipment, maintenance scheduling, and reliability engineering. This updated bibliography contains 347 citations, 85 of which are new additions to the previous edition.

  20. Adaptive Failure Compensation for Aircraft Tracking Control Using Engine Differential Based Model

    NASA Technical Reports Server (NTRS)

    Liu, Yu; Tang, Xidong; Tao, Gang; Joshi, Suresh M.

    2006-01-01

    An aircraft model that incorporates independently adjustable engine throttles and ailerons is employed to develop an adaptive control scheme in the presence of actuator failures. This model captures the key features of aircraft flight dynamics when in the engine differential mode. Based on this model an adaptive feedback control scheme for asymptotic state tracking is developed and applied to a transport aircraft model in the presence of two types of failures during operation, rudder failure and aileron failure. Simulation results are presented to demonstrate the adaptive failure compensation scheme.

  1. Influence of color coatings on aircraft surface ice detection based on multi-wavelength imaging

    NASA Astrophysics Data System (ADS)

    Zhuge, Jing-chang; Yu, Zhi-jing; Gao, Jian-shu; Zheng, Da-chuan

    2016-03-01

    In this paper, a simple aircraft surface ice detection system is proposed based on multi-wavelength imaging. Its feasibility is proved by the experimental results. The influence of color coatings of aircraft surface is investigated. The results show that the ice area can be clearly distinguished from the red, white, gray and blue coatings painted aluminum plates. Due to the strong absorption, not enough signals can be detected for the black coatings. Thus, a deep research is needed. Even though, the results of this paper are helpful to the development of aircraft surface ice detection.

  2. Methane and Other Greenhouse Gas Measurements from Aircraft in Alaska: 2009 - 2011

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Patrick, L.; Newberger, T.; Chen, H.; Oltmans, S. J.; Bruhwiler, L.; Miller, C. E.; Dlugokencky, E. J.; Tans, P. P.

    2011-12-01

    Due to their huge potential impact on the Earth's warming, methane (CH4) emissions in the Arctic are currently widely-studied and debated in the carbon cycle community. Emissions from carbon stored in Arctic soil are projected to increase as the region warms and the permafrost thaws, creating a potent feedback mechanism for climate change. This year, NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) began multi-year aircraft measurements in Alaska, which, coupled with regional modeling of methane fluxes, will evaluate and quantify the effect of regional climate change on ecosystem CO2 and CH4 fluxes. A crucial component of such regional modeling is the choice of background mixing ratio for a given atmospheric sample. A recent addition to the NOAA/GMD aircraft program provides valuable information on background mixing ratios for the Alaskan interior and provides insight into the seasonal cycle and inter-annual variability as well as spatial and temporal context for the measurements being made during the CARVE campaigns. The NOAA/GMD aircraft program began new, ongoing greenhouse gas measurements in Alaska in 2009 (complementing existing ground stations at Barrow and Cold Bay, and a flask-only aircraft site outside of Fairbanks), through a collaboration with the U.S. Coast Guard. Bi-weekly Arctic Domain Awareness flights on C-130 aircraft generally begin in Kodiak, continue to Barrow, and return back to Kodiak after altitude profiles over Kivalina and Galena. On-board measurements include continuous CO2, CH4, CO, and ozone, as well as 24 flask samples analyzed at NOAA for CO2, CH4, CO, and 50 additional gases. In addition to spanning a large geographic region, the measurements also span the entire growing season, from late March to late November each year. We will present data from 2009 - 2011, with a focus on Arctic CH4. The measurements provide us with additional understanding of the various influences on the seasonal cycles of CH4 and CO2

  3. Estimating Aircraft Heading Based on Laserscanner Derived Point Clouds

    NASA Astrophysics Data System (ADS)

    Koppanyi, Z.; Toth, C., K.

    2015-03-01

    Using LiDAR sensors for tracking and monitoring an operating aircraft is a new application. In this paper, we present data processing methods to estimate the heading of a taxiing aircraft using laser point clouds. During the data acquisition, a Velodyne HDL-32E laser scanner tracked a moving Cessna 172 airplane. The point clouds captured at different times were used for heading estimation. After addressing the problem and specifying the equation of motion to reconstruct the aircraft point cloud from the consecutive scans, three methods are investigated here. The first requires a reference model to estimate the relative angle from the captured data by fitting different cross-sections (horizontal profiles). In the second approach, iterative closest point (ICP) method is used between the consecutive point clouds to determine the horizontal translation of the captured aircraft body. Regarding the ICP, three different versions were compared, namely, the ordinary 3D, 3-DoF 3D and 2-DoF 3D ICP. It was found that 2-DoF 3D ICP provides the best performance. Finally, the last algorithm searches for the unknown heading and velocity parameters by minimizing the volume of the reconstructed plane. The three methods were compared using three test datatypes which are distinguished by object-sensor distance, heading and velocity. We found that the ICP algorithm fails at long distances and when the aircraft motion direction perpendicular to the scan plane, but the first and the third methods give robust and accurate results at 40m object distance and at ~12 knots for a small Cessna airplane.

  4. Corrigendum to "Measuring the 3-D wind vector with a weight-shiftmicrolight aircraft" published in Atmos. Meas. Tech., 4, 1421-1444, 2011

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. We draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  5. Integrating the Base of Aircraft Data (BADA) in CTAS Trajectory Synthesizer

    NASA Technical Reports Server (NTRS)

    Abramson, Michael; Ali, Kareem

    2012-01-01

    The Center-Terminal Radar Approach Control (TRACON) Automation System (CTAS), developed at NASA Ames Research Center for assisting controllers in the management and control of air traffic in the extended terminal area, supports the modeling of more than four hundred aircraft types. However, 90% of them are supported indirectly by mapping them to one of a relatively few aircraft types for which CTAS has detailed drag and engine thrust models. On the other hand, the Base of Aircraft Data (BADA), developed and maintained by Eurocontrol, supports more than 300 aircraft types, about one third of which are directly supported, i.e. they have validated performance data. All these data were made available for CTAS by integrating BADA version 3.8 into CTAS Trajectory Synthesizer (TS). Several validation tools were developed and used to validate the integrated code and to evaluate the accuracy of trajectory predictions generated using CTAS "native" and BADA Aircraft Performance Models (APM) comparing them with radar track data. Results of these comparisons indicate that the two models have different strengths and weaknesses. The BADA APM can improve the accuracy of CTAS predictions at least for some aircraft types, especially small aircraft, and for some flight phases, especially climb.

  6. A knowledge based application of the extended aircraft interrogation and display system

    NASA Technical Reports Server (NTRS)

    Glover, Richard D.; Larson, Richard R.

    1991-01-01

    A family of multiple-processor ground support test equipment was used to test digital flight-control systems on high-performance research aircraft. A unit recently built for the F-18 high alpha research vehicle project is the latest model in a series called the extended aircraft interrogation and display system. The primary feature emphasized monitors the aircraft MIL-STD-1553B data buses and provides real-time engineering units displays of flight-control parameters. A customized software package was developed to provide real-time data interpretation based on rules embodied in a highly structured knowledge database. The configuration of this extended aircraft interrogation and display system is briefly described, and the evolution of the rule based package and its application to failure modes and effects testing on the F-18 high alpha research vehicle is discussed.

  7. Aircraft measurements within a warm conveyor belt during the T-NAWDEX-FALCON campaign

    NASA Astrophysics Data System (ADS)

    Schäfler, Andreas; Boettcher, Maxi; Borrmann, Stephan; Busen, Reinhold; Dörnbrack, Andreas; Grams, Christian; Kaufmann, Stefan; Klingebiel, Marcus; Lammen, Yannick; Reutter, Philipp; Rautenhaus, Marc; Schlager, Hans; Sodemann, Harald; Voigt, Christiane; Wernli, Heini

    2013-04-01

    Warm Conveyor Belts (WCBs) are air streams that are highly relevant for the dynamics in the mid-latitudes as they strongly influence the evolution and intensity of northern hemispheric mid-latitude weather systems. For the predictability of cyclones the representation of diabatic processes associated with latent heat release due to phase transitions of water, surface fluxes, or radiative effects are believed to be a limiting factor. Diabatic processes in cyclones strongly depend on the transport of water vapor and are mainly organized and controlled by the coherently ascending WCB air masses. In October 2012 the T-NAWDEX-Falcon (THORPEX-North Atlantic Waveguide and Downstream Impact Experiment) campaign was organized by DLR Oberpfaffenhofen and ETH Zurich. During 9 research flights over Europe in-cloud measurements in WCBs were obtained with the DLR aircraft Falcon. Lagrangian flights were conducted with the aim to measure in the same air mass during different stages of the WCB to quantify the transport of moisture and the net latent heating along WCBs and their importance for forecast errors associated with mid-latitude weather systems. Besides in-situ observations of wind, temperature and humidity to characterize the thermodynamic structure of the WCBs, a set of dropsondes was deployed to gain a complete view on the complex structure of the cyclone. This presentation gives an overview of the three successful IOPs performed during the T-NAWDEX-Falcon campaign. To address forecast uncertainty and to enable flight planning up to four days in advance of the flights novel diagnostics based on deterministic and ensemble prediction NWP data were employed during the campaign. Furthermore a number of different trajectory models were applied for this field experiment. Based on selected flights from one intensive observation period the challenging planning process of Lagrangian matches of flight paths is described and first results are presented.

  8. Estimating regional methane emissions from agriculture using aircraft measurements of concentration profiles

    NASA Astrophysics Data System (ADS)

    Wratt, D. S.; Gimson, N. R.; Brailsford, G. W.; Lassey, K. R.; Bromley, A. M.; Bell, M. J.

    This paper describes a "top-down" approach for estimating regional surface fluxes of methane, and its application to a pastoral farming region in New Zealand. The approach is based on air sampling from aircraft and interpretation by mesoscale dispersion modelling. The goal is an independent cross-check for an agricultural region of "bottom-up" emission estimation methods like those used for inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC). The "top-down" strategy infers emissions over an agricultural region from differences between methane concentrations measured upwind and downwind of the region. The approach was trialed over the Manawatu agricultural region of New Zealand's North Island. As expected, measured concentration differences were largest at low wind speeds (2-3 m s -1 ). However, during these low wind conditions the concentration differences could not be reliably inverted to provide emission estimates, because of the complex variability in air flow caused by topography and land-sea temperature contrasts. Useful emission estimates were obtained during days with higher wind speed (about 8 m s -1), as the strong synoptic-scale flow then suppressed the development of complex local flows. The upwind-downwind concentration differences were smaller during these conditions of stronger flow, so that precision limits to concentration measurements became significant. Methane fluxes (in the range of 20-100 mg m -2 d -1) calculated under the stronger wind speed conditions were consistent with "bottom-up" estimates scaled from per-animal emission factors, enhancing confidence in the inventory-reporting methodology.

  9. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2013-10-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyzer (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne employment. The modified instrument is described. A laboratory characterization was performed to determine the instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation a calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppbv for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppbv. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately considered and the uncertainty is estimated to be 12.4 ppbv. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppbv at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  10. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2014-03-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyser (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne operation. It was characterised in the laboratory with respect to instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation, a calibration strategy is described that utilises CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppb for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppb. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately determined and the uncertainty is estimated to be 12.4 ppb. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppb at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  11. Installations and methods for measurement of aircraft radio components and systems

    NASA Astrophysics Data System (ADS)

    Tetzlaff, Juergen

    1993-01-01

    The requirements and workings of a flight measurement system for measurement of radio frequency systems and components used in flight control and guidance are described. These systems and components consist of radio systems for communication, navigation, flight monitoring (Air Traffic Control (ATC)), and radar systems for flight monitoring (ATC); recognition and protection procedures. A range of subsystems and components for such installations requires in flight testing. In the case of radio systems, this relates primarily to aircaft antenna whose radiation patterns have to be measured in flight. In the case of radar systems for flight monitoring, it is particularly important to have knowledge of the radar cross section of whatever aircraft are involved, in order to estimate system range and probability of detection. Recognition systems (electronic support measurement) require measurement of antenna radiation diagrams and direction, finding antenna accuracy. In order to ascertain the coverage of systems operating electronic countermeasures, it is also necessary to have knowledge of the radiation patterns of the antennae involved. Although the above mentioned system characteristics can also be at least approximately determined by other methods (theoretical calculations, model measurements, and static measurements on the original on ground test rigs), flight measurements, for example for design acceptance of new aircraft types, is neccessary. These provide practical values and make it possible largely to avoid interferences and omissions which could affect the results of the other processes mentioned above.

  12. Large-scale variability in marine stratocumulus clouds defined from simultaneous aircraft and satellite measurements

    NASA Technical Reports Server (NTRS)

    Albrecht, Bruce A.; Barlow, Roy W.

    1990-01-01

    Satellite images often show significant variations in the structure of marine stratocumulus clouds on scales ranging from 10 to 1000 km. This is illustrated where a GOES West satellite image shows a well-defined variation in cloud structure near 32 N, 122 W on 30 June 1987. Aircraft measurements were made with the UK C-130 and the NCAR Electra on this day as part of the FIRE Marine Stratocumulus Intensive Field Observations (IFO). The mean, turbulent, and the microphysical structure of the clouds sampled in these two areas are compared an an attempt is made to explain the differences in cloud structure. In an attempt to identify any systematic differences between the measurements made with the two aircraft, data were analyzed that were collected on 14 July 1987 with the C-130 and the Electra flying in close formation at an altitude of 250 m. The microphysical and turbulence data are being compared in an attempt to explain the differences in the cloud liquid water content obtained with the two aircraft and the differences in cloud structure shown by the GOES image. In addition, data are being analyzed for three other days during the experiment when coordinated downstream flights were made with the Electra and the C-130.

  13. Measurements of Flow Rate and Trajectory of Aircraft Tire-Generated Water Spray

    NASA Technical Reports Server (NTRS)

    Daugherty, Robert H.; Stubbs, Sandy M.

    1987-01-01

    An experimental investigation was conducted at the NASA Langley Research Center to measure the flow rate and trajectory of water spray generated by an aircraft tire operating on a flooded runway. Tests were conducted in the Hydrodynamics Research Facility and made use of a partial airframe and a nose tire from a general aviation aircraft. Nose tires from a commercial transport aircraft were also used. The effects of forward speed, tire load, and water depth on water spray patterns were evaluated by measuring the amount and location of water captured by an array of tubes mounted behind the test tire. Water ejected from the side of the tire footprint had the most significant potential for ingestion into engine inlets. A lateral wake created on the water surface by the rolling tire can dominate the shape of the spray pattern as the distance aft of the tire is increased. Forward speed increased flow rates and moved the spray pattern inboard. Increased tire load caused the spray to become less dense. Near the tire, increased water depths caused flow rates to increase. Tests using a fuselage and partial wing along with the nose gear showed that for certain configurations, wing aerodynamics can cause a concentration of spray above the wing.

  14. Calibration of strain-gage installations in aircraft structures for the measurement of flight loads

    NASA Technical Reports Server (NTRS)

    Skopinski, T H; Aiken, William S , Jr; Huston, Wilber B

    1954-01-01

    A general method has been developed for calibrating strain-gage installations in aircraft structures, which permits the measurement in flight of the shear or lift, the bending moment, and the torque or pitching moment on the principal lifting or control surfaces. Although the stress in structural members may not be a simple function of the three loads of interest, a straightforward procedure is given for numerically combining the outputs of several bridges in such a way that the loads may be obtained. Extensions of the basic procedure by means of electrical combination of the strain-gage bridges are described which permit compromises between strain-gage installation time, availability of recording instruments, and data reduction time. The basic principles of strain-gage calibration procedures are illustrated by reference to the data for two aircraft structures of typical construction, one a straight and the other a swept horizontal stabilizer.

  15. Measurements of fuselage skin strains and displacements near a longitudinal lap joint in a pressurized aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, Edward P.; Britt, Vicki O.

    1991-01-01

    Strains and displacements in a small area near a longitudinal lap joint in the fuselage skin of a B737 aircraft were measured during a pressurization cycle to a differential pressure of 6.2 psi while the aircraft was on the ground. It was found that hoop strains were higher than longitudinal strains at each location; membrane strains in the unreinforced skin were higher than in the joint; membrane strains in the hoop direction, as well as radial displacements, tended to be highest at the mid-bay location between skin reinforcements; significant bending in the hoop direction occurred in the joint and in the skin near the joint, and the bending was unsymmetrically distributed about the stringer at the middle of the joint; and radial displacements were unsymmetrically distributed across the lap joint. The interpretation of the strain gage data for locations on the bonded and riveted lap joint assumed that the joint did not contain disbonded areas.

  16. PIV Measurements of Chevrons on F400 Tactical Aircraft Nozzle Model

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark; Frate, Franco

    2010-01-01

    Previous talks at this meeting have covered our collaborative work on high-energy jets such as present in tactical aircraft (those with supersonic plumes). The emphasis of this work is improving our understanding of flow physics and our prediction tools. In this presentation we will discuss recent flow diagnostics acquired using Particle Image Velocimetry (PIV) made on an underexpanded shocked jet plume from a tactical aircraft nozzle. In this presentation we show cross-sectional and streamwise cuts of both mean and turbulent velocities of an F404 engine nozzle with various chevron designs applied. The impact of chevron penetration, length, and width are documented. The impact of the parameters is generally nonlinear in measures considered here, a surprising result given the relatively smooth behavior of the noise to variations in these chevron parameters.

  17. Quantifying consistency and biases between aircraft, balloon and remote sensing measurements of UT/LS water vapor during the WB-57 NASA MACPEX mission

    NASA Astrophysics Data System (ADS)

    Gao, R.; Rollins, A.; Thornberry, T. D.; Hall, E.; Jordan, A.; Hurst, D. F.; Smith, J. B.; Sargent, M. R.; Fahey, D. W.

    2011-12-01

    Mixing ratios of water vapor in Earth's upper troposphere and lower stratosphere (UT/LS) are low (< 10 ppmv), yet water in this region is a significant driver of climate. Significant discrepancies have repeatedly been observed between multiple high precision measurements of water vapor at these low values in the UT/LS, leading to uncertainty in the absolute value of the direct radiative forcing from stratospheric water vapor. During the NASA Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April of 2011, measurements of water vapor in the UT/LS were made using the NOAA chemical ionization mass spectrometer (CIMS) and Harvard Lyman-α water vapor (HWV) instruments integrated on the NASA WB-57 based out of Ellington Field, TX. This was the first aircraft deployment of the CIMS instrument configured to measure water vapor. The CIMS carried a novel in situ calibration system using two independent water vapor standards that were in excellent agreement throughout the campaign. CIMS was also in excellent agreement with HWV, which operates and is calibrated using fundamentally different principles. The redundant and independent calibration systems of CIMS and HWV afford new confidence in the accuracy of these aircraft measurements. We compare these aircraft measurements of water vapor to those made with the MLS instrument on the AURA satellite, and to frost point balloon borne (NOAA FPH and CFH) measurements coordinated with the WB-57 descents from the LS. A persistent bias of 0.7 ppmv is observed between the frost point and aircraft measurements in the 3 to 10 ppmv range, with frost point being lower. The MLS measurements are less precise, but generally fall between the balloon and aircraft measurements in the LS. These measurements renew interest in comparisons in the tropics where even lower mixing ratios and higher saturations with respect to ice are encountered.

  18. Correction of Doppler Rada Data for Aircraft Motion Using Surface Measurements and Recursive Least-Squares Estimation

    NASA Technical Reports Server (NTRS)

    Durden, S.; Haddad, Z.

    1998-01-01

    Observations of Doppler velocity of hydrometeors form airborne Doppler weather radars normally contains a component due to the aircraft motion. Accurate hydrometeor velocity measurements thus require correction by subtracting this velocity from the observed velocity.

  19. Knowledge-Based Aircraft Automation: Managers Guide on the use of Artificial Intelligence for Aircraft Automation and Verification and Validation Approach for a Neural-Based Flight Controller

    NASA Technical Reports Server (NTRS)

    Broderick, Ron

    1997-01-01

    The ultimate goal of this report was to integrate the powerful tools of artificial intelligence into the traditional process of software development. To maintain the US aerospace competitive advantage, traditional aerospace and software engineers need to more easily incorporate the technology of artificial intelligence into the advanced aerospace systems being designed today. The future goal was to transition artificial intelligence from an emerging technology to a standard technology that is considered early in the life cycle process to develop state-of-the-art aircraft automation systems. This report addressed the future goal in two ways. First, it provided a matrix that identified typical aircraft automation applications conducive to various artificial intelligence methods. The purpose of this matrix was to provide top-level guidance to managers contemplating the possible use of artificial intelligence in the development of aircraft automation. Second, the report provided a methodology to formally evaluate neural networks as part of the traditional process of software development. The matrix was developed by organizing the discipline of artificial intelligence into the following six methods: logical, object representation-based, distributed, uncertainty management, temporal and neurocomputing. Next, a study of existing aircraft automation applications that have been conducive to artificial intelligence implementation resulted in the following five categories: pilot-vehicle interface, system status and diagnosis, situation assessment, automatic flight planning, and aircraft flight control. The resulting matrix provided management guidance to understand artificial intelligence as it applied to aircraft automation. The approach taken to develop a methodology to formally evaluate neural networks as part of the software engineering life cycle was to start with the existing software quality assurance standards and to change these standards to include neural network

  20. The Pope Air Force Base aircraft crash and burn disaster.

    PubMed

    Mozingo, David W; Barillo, David J; Holcomb, John B

    2005-01-01

    This report describes the initial hospital and burn center management of a mass casualty incident resulting from an aircraft crash and fire. One hundred thirty soldiers were injured, including 10 immediate fatalities. Womack Army Medical Center at Fort Bragg, North Carolina, managed the casualties and began receiving patients 15 minutes after the crash. As a result of repetitive training that included at least two mass casualty drills each year, the triage area and emergency department were cleared of all patients within 2 hours. Fifty patients were transferred to burn centers, including 43 patients to the US Army Institute of Surgical Research. This constitutes the largest single mass casualty incident experienced in the 57-year history of the Institute. All patients of the US Army Institute of Surgical Research survived to hospital discharge, and 34 returned to duty 3 months after the crash. The scenario of an on-ground aircraft explosion and fire approximates what might be seen as a result of an aircraft hijacking, bombing, or intentional crash. Lessons learned from this incident have utility in the planning of future response to such disasters.

  1. Terahertz-based relative positioning of aircraft flying in formation

    NASA Astrophysics Data System (ADS)

    Parker, John Scott

    This thesis introduces a new method for estimating the relative positions of aircraft flying in formation using terahertz frequency (THz) signals. We look specifically at the military precision airdrop application, where THz signals have two advantages: (1) stealth due to preferential propagation in the horizontal direction at high altitudes and (2) robustness for operations in GPS-denied environments. This thesis presents two system concepts for implementation. The first, dubbed the straight-and-level (SAL) architecture, produces high precision position estimates during straight and level flight, but suffers from systematic biases when the receiving aircraft performs a maneuver. In support of this architecture, we published the first ever paper on THz relative positioning, and introduced a new filtering method inspired by the well-known GPS Hatch Filter. The second, dubbed the refined-for-maneuvers (RFM) architecture, produces position estimates that are less precise than the SAL architecture, but have no systematic bias when the aircraft maneuver. Simulations are used to predict the performance of the architectures.

  2. The Pope Air Force Base aircraft crash and burn disaster.

    PubMed

    Mozingo, David W; Barillo, David J; Holcomb, John B

    2005-01-01

    This report describes the initial hospital and burn center management of a mass casualty incident resulting from an aircraft crash and fire. One hundred thirty soldiers were injured, including 10 immediate fatalities. Womack Army Medical Center at Fort Bragg, North Carolina, managed the casualties and began receiving patients 15 minutes after the crash. As a result of repetitive training that included at least two mass casualty drills each year, the triage area and emergency department were cleared of all patients within 2 hours. Fifty patients were transferred to burn centers, including 43 patients to the US Army Institute of Surgical Research. This constitutes the largest single mass casualty incident experienced in the 57-year history of the Institute. All patients of the US Army Institute of Surgical Research survived to hospital discharge, and 34 returned to duty 3 months after the crash. The scenario of an on-ground aircraft explosion and fire approximates what might be seen as a result of an aircraft hijacking, bombing, or intentional crash. Lessons learned from this incident have utility in the planning of future response to such disasters. PMID:15756114

  3. Short-range optical air data measurements for aircraft control using rotational Raman backscatter.

    PubMed

    Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

    2013-07-15

    A first laboratory prototype of a novel concept for a short-range optical air data system for aircraft control and safety was built. The measurement methodology was introduced in [Appl. Opt. 51, 148 (2012)] and is based on techniques known from lidar detecting elastic and Raman backscatter from air. A wide range of flight-critical parameters, such as air temperature, molecular number density and pressure can be measured as well as data on atmospheric particles and humidity can be collected. In this paper, the experimental measurement performance achieved with the first laboratory prototype using 532 nm laser radiation of a pulse energy of 118 mJ is presented. Systematic measurement errors and statistical measurement uncertainties are quantified separately. The typical systematic temperature, density and pressure measurement errors obtained from the mean of 1000 averaged signal pulses are small amounting to < 0.22 K, < 0.36% and < 0.31%, respectively, for measurements at air pressures varying from 200 hPa to 950 hPa but constant air temperature of 298.95 K. The systematic measurement errors at air temperatures varying from 238 K to 308 K but constant air pressure of 946 hPa are even smaller and < 0.05 K, < 0.07% and < 0.06%, respectively. A focus is put on the system performance at different virtual flight altitudes as a function of the laser pulse energy. The virtual flight altitudes are precisely generated with a custom-made atmospheric simulation chamber system. In this context, minimum laser pulse energies and pulse numbers are experimentally determined, which are required using the measurement system, in order to meet measurement error demands for temperature and pressure specified in aviation standards. The aviation error margins limit the allowable temperature errors to 1.5 K for all measurement altitudes and the pressure errors to 0.1% for 0 m and 0.5% for 13000 m. With regard to 100-pulse-averaged temperature measurements, the pulse energy using 532 nm

  4. Short-range optical air data measurements for aircraft control using rotational Raman backscatter.

    PubMed

    Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

    2013-07-15

    A first laboratory prototype of a novel concept for a short-range optical air data system for aircraft control and safety was built. The measurement methodology was introduced in [Appl. Opt. 51, 148 (2012)] and is based on techniques known from lidar detecting elastic and Raman backscatter from air. A wide range of flight-critical parameters, such as air temperature, molecular number density and pressure can be measured as well as data on atmospheric particles and humidity can be collected. In this paper, the experimental measurement performance achieved with the first laboratory prototype using 532 nm laser radiation of a pulse energy of 118 mJ is presented. Systematic measurement errors and statistical measurement uncertainties are quantified separately. The typical systematic temperature, density and pressure measurement errors obtained from the mean of 1000 averaged signal pulses are small amounting to < 0.22 K, < 0.36% and < 0.31%, respectively, for measurements at air pressures varying from 200 hPa to 950 hPa but constant air temperature of 298.95 K. The systematic measurement errors at air temperatures varying from 238 K to 308 K but constant air pressure of 946 hPa are even smaller and < 0.05 K, < 0.07% and < 0.06%, respectively. A focus is put on the system performance at different virtual flight altitudes as a function of the laser pulse energy. The virtual flight altitudes are precisely generated with a custom-made atmospheric simulation chamber system. In this context, minimum laser pulse energies and pulse numbers are experimentally determined, which are required using the measurement system, in order to meet measurement error demands for temperature and pressure specified in aviation standards. The aviation error margins limit the allowable temperature errors to 1.5 K for all measurement altitudes and the pressure errors to 0.1% for 0 m and 0.5% for 13000 m. With regard to 100-pulse-averaged temperature measurements, the pulse energy using 532 nm

  5. Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2010-01-01

    A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine which seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared to the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy

  6. Instrumentation and measurement strategy for the NOAA SENEX aircraft campaign as part of the Southeast Atmosphere Study 2013

    NASA Astrophysics Data System (ADS)

    Warneke, Carsten; Trainer, Michael; de Gouw, Joost A.; Parrish, David D.; Fahey, David W.; Ravishankara, A. R.; Middlebrook, Ann M.; Brock, Charles A.; Roberts, James M.; Brown, Steven S.; Neuman, Jonathan A.; Lerner, Brian M.; Lack, Daniel; Law, Daniel; Hübler, Gerhard; Pollack, Iliana; Sjostedt, Steven; Ryerson, Thomas B.; Gilman, Jessica B.; Liao, Jin; Holloway, John; Peischl, Jeff; Nowak, John B.; Aikin, Kenneth C.; Min, Kyung-Eun; Washenfelder, Rebecca A.; Graus, Martin G.; Richardson, Mathew; Markovic, Milos Z.; Wagner, Nick L.; Welti, André; Veres, Patrick R.; Edwards, Peter; Schwarz, Joshua P.; Gordon, Timothy; Dube, William P.; McKeen, Stuart A.; Brioude, Jerome; Ahmadov, Ravan; Bougiatioti, Aikaterini; Lin, Jack J.; Nenes, Athanasios; Wolfe, Glenn M.; Hanisco, Thomas F.; Lee, Ben H.; Lopez-Hilfiker, Felipe D.; Thornton, Joel A.; Keutsch, Frank N.; Kaiser, Jennifer; Mao, Jingqiu; Hatch, Courtney D.

    2016-07-01

    Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeastern US. In addition, anthropogenic emissions are significant in the southeastern US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the southeastern US as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions.

  7. Comparison of remote sensing techniques for measurements of aircraft emissions indices at airports

    NASA Astrophysics Data System (ADS)

    Schaefer, Klaus P.; Jahn, Carsten; Sturm, Peter J.; Lechner, Bernhard; Bacher, Michael; Gostomczyk, Adam; Kabarowska, Barbara; Zalewski, Leszec; Dahl, Guenter

    2004-02-01

    The emission indices of aircraft engine exhausts were measured at airports non-intrusively by FTIR emission spectrometry at the engine nozzle exit as well as by FTIR absorption spectrometry and DOAS (Differential Optical Absorption Spectrometry) behind the aircraft. Two measurement campaigns were performed to compare these different measurement methods. A kerosene powered burner was operated in that way that the different methods were applied for the exhaust gas investigations during the same time and at nearly the same exhaust gas volume. The burner was built with a nozzle exit diameter of 37 cm and a power of about 150 kW. Fresh air was pumped into the burner tube by a fan. Calibration gases as pure CO and NO were added in different amounts to vary the concentration of these gases in the exhaust. The sampling probe of an intrusive measurement system was installed in the centre of the exhaust stream near the exhaust exit for measurements of these gases and CO2 as well as NO2, UHC, SO2 and O2. An APU (GTCP36-300) in a test bed was used in the same way. CO was mixed into the exhausts near the nozzle exit. The passive FTIR instrument was operated in the test bed using special noise and vibration isolation. The open-path instruments were installed at the chimney exit on the roof of the test bed building. The deviations between the different measurement methods were in the order of +/-10 up to +/-20 %.

  8. Measurements of HONO, NO, NOy and SO2 in aircraft exhaust plumes at cruise

    NASA Astrophysics Data System (ADS)

    Jurkat, T.; Voigt, C.; Arnold, F.; Schlager, H.; Kleffmann, J.; Aufmhoff, H.; Schäuble, D.; Schaefer, M.; Schumann, U.

    2011-05-01

    Measurements of gaseous nitrogen and sulfur oxide emissions in young aircraft exhaust plumes give insight into chemical oxidation processes inside aircraft engines. Particularly, the OH-induced formation of nitrous acid (HONO) from nitrogen oxide (NO) and sulfuric acid (H2SO4) from sulfur dioxide (SO2) inside the turbine which is highly uncertain, need detailed analysis to address the climate impact of aviation. We report on airborne in situ measurements at cruise altitudes of HONO, NO, NOy, and SO2 in 9 wakes of 8 different types of modern jet airliners, including for the first time also an A380. Measurements of HONO and SO2 were made with an ITCIMS (Ion Trap Chemical Ionization Mass Spectrometer) using a new ion-reaction scheme involving SF5- reagent ions. The measured molar ratios HONO/NO and HONO/NOy with averages of 0.038 ± 0.010 and 0.027 ± 0.005 were found to decrease systematically with increasing NOx emission-index (EI NOx). We calculate an average EI HONO of 0.31 ± 0.12 g NO2 kg-1. Using reliable measurements of HONO and NOy, which are less adhesive than H2SO4 to the inlet walls, we derive the OH-induced conversion fraction of fuel sulfur to sulfuric acid $\\varepsilon$ with an average of 2.2 ± 0.5 %. $\\varepsilon$ also tends to decrease with increasing EI NOx, consistent with earlier model simulations. The lowest HONO/NO, HONO/NOy and $\\varepsilon$ was observed for the largest passenger aircraft A380.

  9. Aircraft mass budgeting to measure CO2 emissions of Rome, Italy.

    PubMed

    Gioli, Beniamino; Carfora, Maria F; Magliulo, Vincenzo; Metallo, Maria C; Poli, Attilio A; Toscano, Piero; Miglietta, Franco

    2014-04-01

    Aircraft measurements were used to estimate the CO2 emission rates of the city of Rome, assessed against high-resolution inventorial data. Three experimental flights were made, composed of vertical soundings to measure Planetary Boundary Layer (PBL) properties, and circular horizontal transects at various altitudes around the city area. City level emissions and associated uncertainties were computed by means of mass budgeting techniques, obtaining a positive net CO2 flux of 14.7 ± 4.5, 2.5 ± 1.2, and 10.3 ± 1.2 μmol m(-2) s(-1) for the three flights. Inventorial CO2 fluxes at the time of flights were computed by means of spatial and temporal disaggregation of the gross emission inventory, at 10.9 ± 2.5, 9.6 ± 1.3, and 17.4 ± 9.6 μmol m(-2) s(-1). The largest differences between the two dataset are associated with a greater variability of wind speed and direction in the boundary layer during measurements. Uncertainty partitioned into components related to horizontal boundary flows and top surface flow, revealed that the latter dominates total uncertainty in the presence of a wide variability of CO2 concentration in the free troposphere (up to 7 ppm), while it is a minor term with uniform tropospheric concentrations in the study area (within 2 ppm). Overall, we demonstrate how small aircraft may provide city level emission measurements that may integrate and validate emission inventories. Optimal atmospheric conditions and measurement strategies for the deployment of aircraft experimental flights are finally discussed.

  10. A Remotely Piloted Aircraft (RPA) as a Measurement Tool for Wind-Energy Research

    NASA Astrophysics Data System (ADS)

    Wildmann, Norman; Bange, Jens

    2014-05-01

    In wind energy meteorology, RPA have the clear advantage compared to manned aircraft that they allow to fly very close to the ground and even in between individual wind turbines in a wind farm. Compared to meteorological towers and lidar systems, the advantage is the flexibility of the system, which makes it possible to measure at the desired site on short notice and not only in main wind direction. At the Center of Applied Geoscience at the University of Tübingen, the research RPA MASC (Multi-purpose Airborne Sensor Carrier) was developed. RPA of type MASC have a wingspan of about 3 m and a maximum take-off weight of 7.5 kg, including payload. The standard meteorological payload includes instruments for temperature, humidity, barometric pressure and wind measurement. It is possible to resolve turbulence fluctuations of wind and temperature up to 20 Hz. The autopilot ROCS (Research Onboard Computer System), which is developed at the Institute of Flight Mechanics and Control, University of Stuttgart, makes it possible to automatically follow predefined waypoints at constant altitude and airspeed. At a cruising speed of 24 m/s and a battery life of approx. one hour, a range of 80 km is feasible. The project 'Lidar Complex', funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, is part of the research network 'WindForS', based in Southern Germany. The goal of the project is to establish lidar technology for wind energy plant site evaluation in complex terrain. Additional goals are the comparison of different measurement techniques and the validation of wind-field models in not IEC 61400 conform terrain. It is planned to design a turbulent wind-field generator, fed by real measurement data, which can be used to analyse WEC behaviour. Two test sites were defined for the 'Lidar Complex' project, one in IEC-conform terrain about 15 km from the Baltic Sea, the other in the Swabian Alb, only 2 km downstream of a 100 m steep

  11. Two Wavelength Ti:sapphire Laser for Ozone DIAL Measurements from Aircraft

    NASA Technical Reports Server (NTRS)

    Situ, Wen; DeYoung, Russel J.

    1998-01-01

    Laser remote sensing of ozone from aircraft has proven to be a valuable technique for understanding the distribution and dynamics of ozone in the atmosphere. Presently the differential absorption lidar (DIAL) technique, using dual ND:YAG lasers that are doubled to pump dye lasers which in turn are doubled into the UV for the "on" and "off' line lasers, is used on either the NASA DC-8 or P-3 aircraft. Typically, the laser output for each line is 40-mJ and this is split into two beams, one looking up and the other downward, each beam having about 20-mJ. The residual ND:YAG (1.06 micron) and dye laser energies are also transmitted to obtain information on the atmospheric aerosols. While this system has operated well, there are several system characteristics that make the system less than ideal for aircraft operations. The system, which uses separate "on" and "off" line lasers, is quite large and massive requiring valuable aircraft volume and weight. The dye slowly degrades with time requiring replacement. The laser complexity requires a number of technical people to maintain the system performance. There is also the future interest in deploying an ozone DIAL system in an Unpiloted Atmospheric Vehicle (UAV) which would require a total payload mass of less than 150 kg and power requirement of less than 1500 W. A laser technology has emerged that could potentially provide significant enhancements over the present ozone DIAL system. The flashlamp pumped Ti:sapphire laser system is an emerging technology that could reduce the mass and volume over the present system and also provide a system with fewer conversion steps, reducing system complexity. This paper will discuss preliminary results from a flashlamp-pumped Ti:sapphire laser constructed as a radiation source for a UV DIAL system to measure ozone.

  12. New technique for the direct measurement of core noise from aircraft engines

    NASA Technical Reports Server (NTRS)

    Krejsa, E. A.

    1981-01-01

    A new technique is presented for directly measuring the core noise levels from gas turbine aircraft engines. The technique requires that fluctuating pressures be measured in the far-field and at two locations within the engine core. The cross-spectra of these measurements are used to determine the levels of the far-field noise that propagated from the engine core. The technique makes it possible to measure core noise levels even when other noise sources dominate. The technique was applied to signals measured from an AVCO Lycoming YF102 turbofan engine. Core noise levels as a function of frequency and radiation angle were measured and are presented over a range of power settings.

  13. Long-term monitoring of the onboard aircraft exposure level with a Si-diode based spectrometer.

    PubMed

    Spurny, F; Dachev, Ts

    2003-01-01

    The radiation fields onboard aircraft are complex (EURADOS, 1996), and several methods are used to characterise them for radiation protection. We have tested a spectrometer based on Si-diode at different sources and accelerator facilities. The energy deposited in the diode is analysed to estimate the contribution of different radiations to dosimetry quantities. The spectrum of energy deposition events onboard aircraft is similar to that registered in the CERN high-energy reference field. We used this similarity to determine the correction factors to appreciate radiation protection quantities from the results of onboard measurements. During 2001-2002, the spectrometer was used to acquire measurements onboard commercial aircraft during five long-term exposures. All necessary flight parameters were acquired; thus permitting calculations of the onboard effective dose and/or ambient dose equivalent by means of both the CARI 6 and the EPCARD codes and comparison with the results of the measurements. It was found that the apparent ambient dose equivalent values from measured data are in reasonable agreement with the results of calculations. Quantitative analysis of this agreement as a function of flight parameters (geomagnetic position, solar activity variations, etc.) is presented. During one flight, an important solar event (GLE 60 on 15 April 2001) was recorded by the spectrometer. In some other cases the measurements during a Forbush decreases were acquired. These extremes were well registered by the equipment and the data obtained are analyzed.

  14. Airborne measurements performed by a light aircraft during Pegasos spring 2013 campaign

    NASA Astrophysics Data System (ADS)

    Väänänen, Riikka; Krejci, Radovan; Manninen, Hanna E.; Nieminen, Tuomo; Yli-Juuti, Taina; Kangasluoma, Juha; Pohja, Toivo; Aalto, Pasi P.; Petäjä, Tuukka; Kulmala, Markku

    2014-05-01

    To fully understand the chemical and physical processes in atmosphere, measuring only on-ground is not sufficient. To extend the measurements into the lower troposphere, the University of Helsinki has performed airborne campaigns since 2009. During spring 2013, a light aircraft was used to measure the aerosol size distribution over boreal forests as a part of the Pegasos 'Norhern Mission'. The aims of the measurements were to quantify the vertical profiles of aerosols up to the altitude of 3.5 km, to study the new particle formation in the lower troposphere, to measure the planetary boundary layer evolution, and to support the measurements performed by Zeppelin NT. We used a Cessna 172 light aircraft as a platform. An aerosol and gas inlet was mounted under the right wing and the sample air was conducted inside the cabin where most of the instruments were placed. The aerosol measurement instruments included a TSI 3776 condensation particle counter (CPC) with a cut-off size of 3 nm, a Scanning Mobility Particle Sizer (SMPS), with a size range of 10-350 nm, and a Particle Size Magnifier (PSM) connected with a TSI 3772 condensation particle counter. As the properties of the PSM measuring in airborne conditions were still under testing during the campaign, the setups of the PSM varied between the measurements. Other instruments on board included a Li-Cor Li-840 H2O/Co2-analyzer, a temperature sensor, a relative humidity sensor, and a GPS receiver. Total amount of 45 flights with 118 flight hours were performed between 24th April and 15th June 2013. The majority of the flights were flown around SMEAR II station located in Hyytiälä, and when possible, the flights were synchronized with the Zeppelin flights. Simultaneously, an extensive field campaign to measure aerosol and gas properties was performed on-ground at SMEAR II station. A time series of airborne aerosol data of around 1.5 months allows us to construct statistical vertical profiles of aerosol size

  15. Moisture and heat budgets of a cirrus cloud from aircraft measurements during FIRE

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Rao, Gandikota V.

    1993-01-01

    This study is based on the NCAR King Air aircraft and radiosonde observations on 31 October 1986 during the FIRE in Wisconsin over Oshkosh. Aircraft step-up and spiral descent flights are used to obtain kinematic and thermodynamic data. In the step-up maneuver, six different penetrations were made between 1528 and 1616 UTC. Each penetration was about 30 km long separated in the vertical by about 300 m. The time difference between the two spiral soundings was about 43 min. The aircraft descended at a rate of 1.5 m/s during these spiral soundings. Kinematic, cloud physical, and radiometric observations from various instruments are used to estimate the different terms in the moisture- and heat-budget equations. The results show that the advection terms, estimated using the mean longitudinal wind and vertical velocities, and radiative fluxes are important in forming budgets for the cirrus layers. Ice-crystal growth is significant in the upper layers. The maintenance of cirrus can be attributed to relatively warm and moist air advection, radiative cooling at upper levels, and moisture advection in the vertical. Turbulent heat and moisture fluxes are found to be significant in the low levels of cirrus.

  16. Flight test validation of a frequency-based system identification method on an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Schkolnik, Gerard S.; Orme, John S.; Hreha, Mark A.

    1995-01-01

    A frequency-based performance identification approach was evaluated using flight data from the NASA F-15 Highly Integrated Digital Electronic Control aircraft. The approach used frequency separation to identify the effectiveness of multiple controls simultaneously as an alternative to independent control identification methods. Fourier transformations converted measured control and response data into frequency domain representations. Performance gradients were formed using multiterm frequency matching of control and response frequency domain models. An objective function was generated using these performance gradients. This function was formally optimized to produce a coordinated control trim set. This algorithm was applied to longitudinal acceleration and evaluated using two control effectors: nozzle throat area and inlet first ramp. Three criteria were investigated to validate the approach: simultaneous gradient identification, gradient frequency dependency, and repeatability. This report describes the flight test results. These data demonstrate that the approach can accurately identify performance gradients during simultaneous control excitation independent of excitation frequency.

  17. Characterisation of a hybrid, fuel-cell-based propulsion system for small unmanned aircraft

    NASA Astrophysics Data System (ADS)

    Verstraete, D.; Lehmkuehler, K.; Gong, A.; Harvey, J. R.; Brian, G.; Palmer, J. L.

    2014-03-01

    Advanced hybrid powerplants combining a fuel cell and battery can enable significantly higher endurance for small, electrically powered unmanned aircraft systems, compared with batteries alone. However, detailed investigations of the static and dynamic performance of such systems are required to address integration challenges. This article describes a series of tests used to characterise the Horizon Energy Systems' AeroStack hybrid, fuel-cell-based powertrain. The results demonstrate that a significant difference can exist between the dynamic performance of the fuel-cell system and its static polarisation curve, confirming the need for detailed measurements. The results also confirm that the AeroStack's lithium-polymer battery plays a crucial role in its response to dynamic load changes and protects the fuel cell from membrane dehydration and fuel starvation. At low static loads, the AeroStack fuel cell recharges the battery with currents up to 1 A, which leads to further differences with the polarisation curve.

  18. Visible and near-infrared channel calibration of the GOES-6 VISSR using high-altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Smith, Gilbert R.; Levin, Robert H.; Koyanagi, Robert S.; Wrigley, Robert C.

    1989-01-01

    Present and future visible and near-infrared wavelength sensors mounted on operational satellites do not have on-board absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurements of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Aircraft data were recorded over White Sands, New Mexico, and the coincident aircraft and orbiting satellite data is compared for the visible and near-infrared wavelength channel of the GOES-6 Visible Infrared Spin-Scan Radiometer.

  19. An Evidenced-Based Approach for Estimating Decompression Sickness Risk in Aircraft Operations

    NASA Technical Reports Server (NTRS)

    Robinson, Ronald R.; Dervay, Joseph P.; Conkin, Johnny

    1999-01-01

    Estimating the risk of decompression Sickness (DCS) in aircraft operations remains a challenge, making the reduction of this risk through the development of operationally acceptable denitrogenation schedules difficult. In addition, the medical recommendations which are promulgated are often not supported by rigorous evaluation of the available data, but are instead arrived at by negotiation with the aircraft operations community, are adapted from other similar aircraft operations, or are based upon the opinion of the local medical community. We present a systematic approach for defining DCS risk in aircraft operations by analyzing the data available for a specific aircraft, flight profile, and aviator population. Once the risk of DCS in a particular aircraft operation is known, appropriate steps can be taken to reduce this risk to a level acceptable to the applicable aviation community. Using this technique will allow any aviation medical community to arrive at the best estimate of DCS risk for its specific mission and aviator population and will allow systematic reevaluation of the decisions regarding DCS risk reduction when additional data are available.

  20. Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft.

    PubMed

    Melamed, M L; Solomon, S; Daniel, J S; Langford, A O; Portmann, R W; Ryerson, T B; Nicks, D K; McKeen, S A

    2003-02-01

    Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.

  1. Remote measurement of the plume shape of aircraft exhausts at airports by passive FTIR spectrometry

    NASA Astrophysics Data System (ADS)

    Schafer, Klaus; Jahn, Carsten; Utzig, Selina; Flores-Jardines, Edgar; Harig, Roland; Rusch, Peter

    2004-11-01

    Information about the interaction between the exhaust plume of an aircraft jet engine and ambient air is required for the application of small-scale chemistry-transport models to investigate airport air quality. This interaction is not well understood. In order to study the interaction, spatial information about the plume is required. FTIR emission spectroscopy may be applied to analyze the aircraft exhausts. In order to characterize the plumes spatially, a scanning imaging FTIR system (SIGIS) has been improved. SIGIS is comprised of an interferometer (Bruker OPAG), an azimuth-elevation-scanning mirror, a data acquisition and control system with digital signal processors (DSP), an infrared camera and a personal computer. With this instrumentation it is possible to visualise the plume and to obtain information about the temperature distribution within the plume. Measurements are performed at low spectral resolution, because the dynamic environment of these measurements limits the measurement time to about 2 minutes. Measurements of the plume shapes of an APU and of main engines were performed.

  2. Aircraft measurements of aerosol properties during GoAmazon - G1 and HALO inter-comparison

    NASA Astrophysics Data System (ADS)

    Mei, F.; Cecchini, M. A.; Wang, J.; Tomlinson, J. M.; Comstock, J. M.; Hubbe, J. M.; Pekour, M. S.; Machado, L.; Wendisch, M.; Longo, K.; Martin, S. T.; Schmid, B.; Weinzierl, B.; Krüger, M. L.; Zöger, M.

    2015-12-01

    Currently, the indirect effects of atmospheric aerosols remain the most uncertain components in forcing of climate change over the industrial period (IPCC, 2013). This large uncertainty is partially a result of our incomplete understanding of the ability of particles to form cloud droplets under atmospherically relevant supersaturations. One objective of the US Department of Energy (DOE) Green Ocean Amazon Project (GoAmazon2014/5) is to understand the influence of the emission from Manaus, a tropical megacity, on aerosol size, concentration, and chemical composition, and their impact on cloud condensation nuclei (CCN) spectrum. The GoAmazon2014/5 study was an international campaign with the collaboration efforts from US, Brazil and Germany. During the intensive operation period, in the dry season (Sep. 1st - Oct. 10th, 2014), aerosol concentration, size distributions, and CCN spectra, both under pristine conditions and inside the Manaus plume, were characterized in-situ from the DOE Gulfstream-1 (G-1) research aircraft and German HALO aircraft during 4 coordinated flights on Sep. 9th, Sep. 16th, Sep 21st and Oct. 1st, 2014. During those four flights, aerosol number concentrations and CCN concentrations at two supersaturations (0.25% and 0.5%) were measured by condensation particle counters (CPCs) and a DMT dual column CCN counter onboard both G-1 and HALO. Aerosol size distribution was also measured by a Fast Integrated Mobility Spectrometer (FIMS) aboard the G-1 and is compared with the size distribution from Ultra High Sensitivity Aerosol Spectrometer - Airborne (UHSAS-A, DMT), which were deployed both on the G-1 and the HALO. Good agreement between the aerosol properties measured from the two aircraft has been achieved. The vertical profiles of aerosol size distribution and CCN spectrum will be discussed.

  3. A Backward Modeling Study of Intercontinental Pollution Transport Using Aircraft Measurements

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Eckhardt, S.; Huntrieser, H.; Heland, J.; Schlager, H.; Aufmhoff, H.; Arnold, F.; Cooper, O.

    2002-12-01

    In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. First, forward calculations of emission tracers from North America, Europe and Asia were made to understand the transport processes. Both episodes were preceded by stagnant conditions over North America, leading to the accumulation of pollutants in the North American boundary layer. This pollution was then exported by warm conveyor belts to the middle and upper troposphere, and transported rapidly to Europe. Concentrations of many chemical trace species (CO, NOy, CO2, acetone, and several VOCs; O3 in one case) measured aboard the research aircraft were clearly enhanced in the pollution plumes compared to the conditions outside the plumes. Backward simulations with the particle model were introduced as an indispensable tool for a more detailed analysis of the plume's source region. They make trajectory analyses, which to date were mainly used to interpret aircraft measurement data, obsolete for establishing source-receptor relationships. Using an emission inventory, we could decompose the tracer mixing ratios at the receptors (i.e., along the flight tracks) into contributions from every grid cell of the inventory. For both North America plumes, we found that emission sources contributing to the tracer concentrations over Europe were distributed over large areas in North America. In one case, the region around New York was clearly the largest contributor, but in the other case, sources in California, Texas, and Florida contributed almost equally. Smaller contributions were made by sources reaching from the Yucatan peninsula to Canada in this case.

  4. Daytime aircraft HONO Measurements over water surface during NOMASS Field Study

    NASA Astrophysics Data System (ADS)

    Ye, C.; Pu, D.; Zhou, X.; Stutz, J.; Mauldin, R.; Cantrell, C. A.; Weinheimer, A. J.; Knapp, D. J.; Haggerty, J. A.; Campos, T. L.; Guenther, A. B.; Kaser, L.; Jensen, J. B.

    2013-12-01

    The NOMDASS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) study is an NSF sponsored airborne experiment, integrating 3 PI-initiated projects: the NAAMEX (The North American Airborne Mercury Experiment), the SOAS (Southern Oxidant and Aerosol Study), and the TROPHONO (TROPospheric HONO) projects. During the NOMDASS field campaign from June 1 to July 15, 2013, based in Smyrna, TN, HONO was measured onboard NCAR's C-130 research aircraft in 19 research flights. In order to study in situ HONO production (i.e., volume production) within air masses, four research flights were designed and conducted over open waters to eliminate potential HONO contributions from ground surface sources. In the 2 inflow flights over the Atlantic Ocean off of the Carolina coast, up to 15 ppt HONO was observed in the clean marine boundary layer (MBL). To sustain the observed levels of HONO, a significant in situ HONO source, at a rate of ~60 ppt hr-1, must exist. Since the NOx mixing ratio was very low, ~ 40 ppt, NOx is unlikely to be a significant HONO precursor in the clean MBL. On the other hand, significant levels of particular nitrate were observed, up to 50 ppt. Photolysis of particulate nitrate may be a significant or even a major HONO source and may be an important re-NOx-ification pathway in this clean and low-NOx marine environment. In a flight over the Gulf of Mexico off of Houston, up to 40 ppt HONO was observed in the Houston plume; in a flight over Lake Michigan, up to 60 ppt HONO was observed in the Chicago plume. At elevated concentrations in urban plumes, HONO may be a significant OH precursor and may play an important role in the photochemical evolution of urban plume.

  5. A solid-state converter for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Shope, W. W.

    1974-01-01

    A solid-state converter, used in a system of instrumentation for measuring aircraft noise and sonic boom, features a dual-gate FET mixer and an output stage designed for compatibility with a zero drive amplifier. With a half-inch condenser microphone the converter itself has an operating frequency range from dc-28 kHz (-3 dB), a dynamic range of 72 dB, and a noise floor of 50 dB in the band from 22.4 Hz to 22.4 kHz; the system requires no impedance matching networks and is insensitive to cable length up to at least 3000 ft.

  6. Remote measurements of the structure of midwest thunderstorm tops and anvils from high altitude aircraft

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Fulton, Richard

    1990-01-01

    Results are presented from observations by a visible and IR scanning radiometer, a scanning passive microwave radiometer, and a nadir-viewing cloud lidar system (CLS), carried out from ER-2 overflights for two midwest severe weather events both of which presented following phenomena: (1) a group of severe thunderstorms which later transformed into a linear mesoscale convective system, and (2) a severe thunderstorm which produced large hail. Most of the aircraft in situ and remote measurements pointed to a deep subsidence region and gravity waves downstream of the overshooting cloud tops. The observations do not support a radiative explanation for the warm areas in the anvil.

  7. Fault Detection of Aircraft System with Random Forest Algorithm and Similarity Measure

    PubMed Central

    Park, Wookje; Jung, Sikhang

    2014-01-01

    Research on fault detection algorithm was developed with the similarity measure and random forest algorithm. The organized algorithm was applied to unmanned aircraft vehicle (UAV) that was readied by us. Similarity measure was designed by the help of distance information, and its usefulness was also verified by proof. Fault decision was carried out by calculation of weighted similarity measure. Twelve available coefficients among healthy and faulty status data group were used to determine the decision. Similarity measure weighting was done and obtained through random forest algorithm (RFA); RF provides data priority. In order to get a fast response of decision, a limited number of coefficients was also considered. Relation of detection rate and amount of feature data were analyzed and illustrated. By repeated trial of similarity calculation, useful data amount was obtained. PMID:25057508

  8. Radiation profiles through the atmosphere measured by an auto controlled glider aircraft

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2014-05-01

    In 2011 radiation measurements through the atmosphere were made with a balloon borne short- and longwave net radiometer. These measurements were very promising and therefore new and improved sensors from Kipp&Zonen were used to equip a glider aircraft together with the standard Swiss radiosonde from Meteolabor AG. The glider serves as returning platform for the expensive and well calibrated radiation sensors. Double balloon technique is used to prevent pendulum motion during the ascent and to keep the radiation instruments as horizontal as possible. The built-in autopilot allows to return the gliderradiosonde to the launch site or to land it on predefined open space, which makes recovery much easier. The new return gliderradiosonde technique as well as new measurement possibilities will be shown. First measurements show radiation profiles through the atmosphere during different cloud conditions. Radiation profiles during different daytimes show the temporal resolution of vertical radiation profiles trough the atmosphere.

  9. Absorption of Solar Radiation by the Cloudy Atmosphere: Further Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, Minghua; Valero, Francisco P. J.; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Zender, Charles S.

    1998-01-01

    We have extended the interpretations made in two prior studies of the aircraft shortwave radiation measurements that were obtained as part of the Atmospheric Radiation Measurements (ARM) Enhanced Shortwave Experiments (ARESE). These extended interpretations use the 500 nm (10 nm bandwidth) measurements to minimize sampling errors in the broadband measurements. It is indicated that the clouds present during this experiment absorb more shortwave radiation than predicted by clear skies and thus by theoretical models, that at least some (less than or equal to 20%) of this enhanced cloud absorption occurs at wavelengths less than 680 nm, and that the observed cloud absorption does not appear to be an artifact of sampling errors nor of instrument calibration errors.

  10. Polarized Imaging Nephelometer for Field and Aircraft Measurements of Aerosol Phase Function

    NASA Astrophysics Data System (ADS)

    Dolgos, G.; Martins, J.

    2012-12-01

    Aerosols have a significant impact on the radiative balance and water cycle of our planet through influencing atmospheric radiation. Remote sensing of aerosols relies on scattering phase matrix information to retrieve aerosol properties with frequent global coverage. At the Laboratory for Aerosols, Clouds and Optics (LACO) at the University of Maryland, Baltimore County we developed a new technique to directly measure the aerosol phase function and the degree of linear polarization of the scattered light (two elements of the phase matrix). We designed and built a portable instrument called the Polarized Imaging Nephelometer (PI-Neph). The PI-Neph successfully participated in dozens of flights of the NASA Development and Evaluation of satellite ValidatiOn Tools by Experimenters (DEVOTE) project and the Deep Convective Clouds and Chemistry (DC3) project. The ambient aerosol enters the PI-Neph through an inlet and the sample is illuminated by laser light (wavelength of 532 nm); the scattered light is imaged by a stationary wide field of view camera in the scattering angle range of 2° to 178°. (In some cases stray light limited the scattering angle range to 3° to 176°). The PI-Neph measurement of phase function and the AERONET (AErosol RObotic NETwork) retrievals have already been compared in some cases when the aircraft spiraled over AERONET sites, for example at NASA's Wallops Flight Facility, on October 18 2011, as shown in Figure 1. The differences between the PI-Neph and the AERONET retrievals can be attributed to differences between the ambient size distribution and the one sampled inside the aircraft. The data that is resolved with respect to scattering angle is used to compute the volume scattering coefficient. The above mentioned October 18 flight data showed good agreement between the PI-Neph measurements of volume scattering coefficient and the parallel TSI integrating nephelometer measurements. On average the TSI measurements were 1.02 times the PI

  11. SIERRA-Flux: Measuring Regional Surface Fluxes of Carbon Dioxide, Methane, and Water Vapor from an Unmanned Aircraft System

    NASA Technical Reports Server (NTRS)

    Fladeland; Yates, Emma Louise; Bui, Thaopaul Van; Dean-Day, Jonathan; Kolyer, Richard

    2011-01-01

    The Eddy-Covariance Method for quantifying surface-atmosphere fluxes is a foundational technique for measuring net ecosystem exchange and validating regional-to-global carbon cycle models. While towers or ships are the most frequent platform for measuring surface-atmosphere exchange, experiments using aircraft for flux measurements have yielded contributions to several large-scale studies including BOREAS, SMACEX, RECAB by providing local-to-regional coverage beyond towers. The low-altitude flight requirements make airborne flux measurements particularly dangerous and well suited for unmanned aircraft.

  12. Measurements of Aircraft Wake Vortex Separation at High Arrival Rates and a Proposed New Wake Vortex Separation Philosophy

    NASA Technical Reports Server (NTRS)

    Rutishauser, David; Donohue, George L.; Haynie, Rudolph C.

    2003-01-01

    This paper presents data and a proposed new aircraft wake vortex separation standard that argues for a fundamental re-thinking of international practice. The current static standard, under certain atmospheric conditions, presents an unnecessary restriction on system capacity. A new approach, that decreases aircraft separation when atmospheric conditions dictate, is proposed based upon the availability of new instrumentation and a better understanding of wake physics.

  13. A new fast response instrument for measuring total water content from aircraft

    NASA Astrophysics Data System (ADS)

    Nicholls, S.; Leighton, J.; Barker, R.

    1990-10-01

    A device for measuring the total water content of a parcel of air from an aircraft has been developed. The total water of a parcel of air is a conserved quantity, independent of phase changes, provided there is no transport of water through the parcel boundaries. Current airborne hygrometers normally attempt to measure the water content in individual phases and the presence of other phases invariably influences the quality of the data. However, any liquid water or ice entering this new probe is efficiently evaporated and the resultant water vapor measured using a Lyman-alpha hygrometer. In airborne trials the device was calibrated against a cooled-mirror dewpoint device. Runs were conducted in warm stratocumulus tops, through small cumulus, in mixed-phase precipitation and cirrus cloud. In all cases the device was found to produce high quality, fast response data.

  14. Feasibility of a nuclear gauge for fuel quantity measurement aboard aircraft

    NASA Technical Reports Server (NTRS)

    Signh, J. J.; Mall, G. H.; Sprinkle, D. R.; Chegini, H.

    1986-01-01

    Capacitance fuel gauges have served as the basis for fuel quantity indicating systems in aircraft for several decades. However, there have been persistent reports by the airlines that these gauges often give faulty indications due to microbial growth and other contaminants in the fuel tanks. This report describes the results of a feasibility study of using gamma ray attenuation as the basis for measuring fuel quantity in the tanks. Studies with a weak Am-241 59.5-keV radiation source indicate that it is possible to continuously monitor the fuel quantity in the tanks to an accuracy of better than 1 percent. These measurements also indicate that there are easily measurable differences in the physical properties and resultant attenuation characteristics of JP-4, JP-5, and Jet A fuels. The experimental results, along with a suggested source-detector geometrical configuration are described.

  15. Two-frequency /Delta k/ microwave scatterometer measurements of ocean wave spectra from an aircraft

    NASA Technical Reports Server (NTRS)

    Johnson, J. W.; Jones, W. L.; Weissman, D. E.

    1981-01-01

    A technique for remotely sensing the large-scale gravity wave spectrum on the ocean surface using a two frequency (Delta k) microwave scatterometer has been demonstrated from stationary platforms and proposed from moving platforms. This measurement takes advantage of Bragg type resonance matching between the electromagnetic wavelength at the difference frequency and the length of the large-scale surface waves. A prominent resonance appears in the cross product power spectral density (PSD) of the two backscattered signals. Ku-Band aircraft scatterometer measurements were conducted by NASA in the North Sea during the 1979 Maritime Remote Sensing (MARSEN) experiment. Typical examples of cross product PSD's computed from the MARSEN data are presented. They demonstrate strong resonances whose frequency and bandwidth agree with the surface characteristics and the theory. Directional modulation spectra of the surface reflectivity are compared to the gravity wave spectrum derived from surface truth measurements.

  16. The Arctic polar stratospheric cloud aerosol - Aircraft measurements of reactive nitrogen, total water, and particles

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Fahey, D. W.; Kelly, K. K.; Dye, J. E.; Baumgardner, D.; Gandrud, B. W.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.

    1992-01-01

    In situ aircraft measurements in the lower stratosphere are used to investigate the reactive nitrogen, NO(y), total water, and particle components of the polar stratospheric cloud (PSC) aerosol in the Arctic. The results are compared to findings from the Antarctic derived using similar measurements and interpretive techniques. The Arctic data show that particle volume well above background values is present at temperatures above the frostpoint, confirming the result from the Antarctic that the observed PSCs are not water ice particles. NO(y) measurements inside a PSC are enhanced above ambient values consistent with anisokinetic sampling of particles containing NO(y). In the Arctic data over long segments of several flights, calculations show saturation with respect to nitric acid trihydrate without significant PSC particle growth above background.

  17. Dual-parameter radar rainfall measurement from space - A test result from an aircraft experiment

    NASA Technical Reports Server (NTRS)

    Kozu, Toshiaki; Nakamura, Kenji; Meneghini, Robert; Boncyk, Wayne C.

    1991-01-01

    An aircraft experiment has been conducted with a dual-frequency (X/Ka-bands) radar to test various rainfall retrieval methods from space. The authors test a method to derive raindrop size distribution (DSD) parameters from the combination of a radar reflectivity profile and a path-integrated attenuation derived from surface return, which may be available from most spaceborne radars. The estimated DSD parameters are reasonable in that the values generally fall within the range of commonly measured ones and that shifts in DSD parameters appear to be correlated with changes in storm type. The validity of the estimation result is also demonstrated by a consistency check using the Ka-band reflectivity profile which is independent of the DSD estimation process. Although errors may occur in the cases of nonuniform beam filling, these test results indicate the feasibility of the dual-parameter radar measurement from space in achieving a better accuracy in quantitative rainfall remote measurements.

  18. The measurement of aircraft performance and stability and control after flight through natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Ide, R. F.; Reehorst, A. L.; Jordan, J. L.; Schinstock, W. C.; Platz, S. J.

    1986-01-01

    The effects of airframe icing on the performance and stability and control of a twin-engine commuter-class aircraft were measured by the NASA Lewis Research Center. This work consisted of clear air tests with artificial ice shapes attached to the horizontal tail, and natural icing flight tests in measured icing clouds. The clear air tests employed static longitudinal flight test methods to determine degradation in stability margins for four simulated ice shapes. The natural icing flight tests employed a data acquisition system, which was provided under contract to NASA by Kohlman Systems Research Incorporated. This system used a performance modeling method and modified maximum likelihood estimation (MMLE) technique to determine aircraft performance degradation and stability and control. Flight test results with artificial ice shapes showed that longitudinal, stick-fixed, static margins are reduced on the order of 5 percent with flaps up. Natural icing tests with the KSR system corroborated these results and showed degradation in the elevator control derivatives on the order of 8 to 16 percent depending on wing flap configuration. Performance analyses showed the individual contributions of major airframe components to the overall degration in lift and drag.

  19. The measurement of aircraft performance and stability and control after flight through natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Ide, R. F.; Reehorst, A. L.

    1986-01-01

    The effects of airframe icing on the performance and stability and control of a twin-engine commuter-class aircraft were measured by the NASA Lewis Research Center. This work consisted of clear air tests with artificial ice shapes attached to the horizontal tail, and natural icing flight tests in measured icing clouds. The clear air tests employed static longitudinal flight test methods to determine degradation in stability margins for four simulated ice shapes. The natural icing flight tests employed a data acquisition system, which was provided under contract to NASA by Kohlman Systems Research Incorporated. This system used a performance modeling method and modified maximum likelihood estimation (MMLE) technique to determine aircraft performance degradation and stability and control. Flight test results with artificial ice shapes showed that longitudinal, stick-fixed, static margins are reduced on the order of 5 percent with flaps up. Natural icing tests with the KSR system corroborated these results and showed degradation in the elevator control derivatives on the order of 8 to 16 percent depending on wing flap configuration. Performance analyses showed the individual contributions of major airframe components to the overall degradation in lift and drag.

  20. Simulation-Based Airframe Noise Prediction of a Full-Scale, Full Aircraft

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Fares, Ehab

    2016-01-01

    A previously validated computational approach applied to an 18%-scale, semi-span Gulfstream aircraft model was extended to the full-scale, full-span aircraft in the present investigation. The full-scale flap and main landing gear geometries used in the simulations are nearly identical to those flown on the actual aircraft. The lattice Boltzmann solver PowerFLOW® was used to perform time-accurate predictions of the flow field associated with this aircraft. The simulations were performed at a Mach number of 0.2 with the flap deflected 39 deg. and main landing gear deployed (landing configuration). Special attention was paid to the accurate prediction of major sources of flap tip and main landing gear noise. Computed farfield noise spectra for three selected baseline configurations (flap deflected 39 deg. with and without main gear extended, and flap deflected 0 deg. with gear deployed) are presented. The flap brackets are shown to be important contributors to the farfield noise spectra in the mid- to high-frequency range. Simulated farfield noise spectra for the baseline configurations, obtained using a Ffowcs Williams and Hawkings acoustic analogy approach, were found to be in close agreement with acoustic measurements acquired during the 2006 NASA-Gulfstream joint flight test of the same aircraft.

  1. PIV Measurements of Chevrons on F400-Series Tactical Aircraft Nozzle Model

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.; Frate, Franco C.

    2011-01-01

    Reducing noise of tactical jet aircraft has taken on fresh urgency as core engine technologies allow higher specific-thrust engines and as society become more concerned for the health of its military workforce. Noise reduction on this application has lagged the commercial field as incentives for quieting military aircraft have not been as strong as in their civilian counterparts. And noise reduction strategies employed on civilian engines may not be directly applicable due to the differences in exhaust system architecture and mission. For instance, the noise reduction technology of chevrons, examined in this study, will need to be modified to take into account the special features of tactical aircraft nozzles. In practice, these nozzles have divergent slats that are tied to throttle position, and at take off the jet flow is highly overexpanded as the nozzle is optimized for cruise altitude rather than sea level. In simple oil flow visualization experiments conducted at the onset of the current test program flow barely stays attached at end of nozzle at takeoff conditions. This adds a new twist to the design of chevrons. Upon reaching the nozzle exit the flow shrinks inward radially, meaning that for a chevron to penetrate the flow it must extend much farther away from the baseline nozzle streamline. Another wrinkle is that with a variable divergence angle on the nozzle, the effective penetration will differ with throttle position and altitude. The final note of realism introduced in these experiments was to simulate the manner in which bypass flow is bled into the nozzle wall in real engines to cool the nozzle, which might cause very fat boundary layer at exit. These factors, along with several other issues specific to the application of chevrons to convergent-divergent nozzles have been explored with particle image velocimetry measurements and are presented in this paper.

  2. Longitudinal control of aircraft dynamics based on optimization of PID parameters

    NASA Astrophysics Data System (ADS)

    Deepa, S. N.; Sudha, G.

    2016-03-01

    Recent years many flight control systems and industries are employing PID controllers to improve the dynamic behavior of the characteristics. In this paper, PID controller is developed to improve the stability and performance of general aviation aircraft system. Designing the optimum PID controller parameters for a pitch control aircraft is important in expanding the flight safety envelope. Mathematical model is developed to describe the longitudinal pitch control of an aircraft. The PID controller is designed based on the dynamic modeling of an aircraft system. Different tuning methods namely Zeigler-Nichols method (ZN), Modified Zeigler-Nichols method, Tyreus-Luyben tuning, Astrom-Hagglund tuning methods are employed. The time domain specifications of different tuning methods are compared to obtain the optimum parameters value. The results prove that PID controller tuned by Zeigler-Nichols for aircraft pitch control dynamics is better in stability and performance in all conditions. Future research work of obtaining optimum PID controller parameters using artificial intelligence techniques should be carried out.

  3. Modeling and assessment of civil aircraft evacuation based on finer-grid

    NASA Astrophysics Data System (ADS)

    Fang, Zhi-Ming; Lv, Wei; Jiang, Li-Xue; Xu, Qing-Feng; Song, Wei-Guo

    2016-04-01

    Studying civil aircraft emergency evacuation process by using computer model is an effective way. In this study, the evacuation of Airbus A380 is simulated using a Finer-Grid Civil Aircraft Evacuation (FGCAE) model. In this model, the effect of seat area and others on escape process and pedestrian's "hesitation" before leaving exits are considered, and an optimized rule of exit choice is defined. Simulations reproduce typical characteristics of aircraft evacuation, such as the movement synchronization between adjacent pedestrians, route choice and so on, and indicate that evacuation efficiency will be determined by pedestrian's "preference" and "hesitation". Based on the model, an assessment procedure of aircraft evacuation safety is presented. The assessment and comparison with the actual evacuation test demonstrate that the available exit setting of "one exit from each exit pair" used by practical demonstration test is not the worst scenario. The half exits of one end of the cabin are all unavailable is the worst one, that should be paid more attention to, and even be adopted in the certification test. The model and method presented in this study could be useful for assessing, validating and improving the evacuation performance of aircraft.

  4. Characterizing a Wake-Free Safe Zone for the Simplified Aircraft-Based Paired Approach Concept

    NASA Technical Reports Server (NTRS)

    Guerreiro, Nelson M.; Neitzke, Kurt W.; Johnson, Sally C.; Stough, H. Paul, III; McKissick, Burnell T.; Syed, Hazari I.

    2010-01-01

    The Federal Aviation Administration (FAA) has proposed a concept of operations geared towards achieving increased arrival throughput at U.S. Airports, known as the Simplified Aircraft-based Paired Approach (SAPA) concept. In this study, a preliminary characterization of a wake-free safe zone (WFSZ) for the SAPA concept has been performed. The experiment employed Monte-Carlo simulations of varying approach profiles by aircraft pairs to closely-spaced parallel runways. Three different runway lateral spacings were investigated (750 ft, 1000 ft and 1400 ft), along with no stagger and 1500 ft stagger between runway thresholds. The paired aircraft were flown in a leader/trailer configuration with potential wake encounters detected using a wake detection surface translating with the trailing aircraft. The WFSZ is characterized in terms of the smallest observed initial in-trail distance leading to a wake encounter anywhere along the approach path of the aircraft. The results suggest that the WFSZ can be characterized in terms of two primary altitude regions, in ground-effect (IGE) and out of ground-effect (OGE), with the IGE region being the limiting case with a significantly smaller WFSZ. Runway stagger was observed to only modestly reduce the WFSZ size, predominantly in the OGE region.

  5. Aircraft-based in-situ calibration of a hot-wire anemometer in a compressible flow

    NASA Astrophysics Data System (ADS)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Bishop, Kenneth P.; McCrae, Kimberley A.

    1999-08-01

    High-bandwidth measurements of atmospheric velocity and temperature fluctuations in the high troposphere/low stratosphere using aircraft-based hot-wire anemometers requires calibration. An in-situ calibration characterizing wire sensitivity at high subsonic Mach numbers and relatively low temperatures and pressures was performed. Custom designed constant-temperature and constant-current anemometer equipment has been used for these atmospheric measurements. Two sets of calibration experiments are described, one in a controlled laboratory environment where the Mach number and temperature were varied and the other on board a C-135E aircraft. The aircraft test were conducted by varying the flight Mach number at different pressure altitudes while flying into an upper-level low pressure area, achieving variability in velocity, temperature, and pressure. Results obtained indicate increased sensitivity to velocity while operating the wire at a low overheat ratio. The calibration data was fit to a form of King's law which was found to work well for in-situ calibrations.

  6. 14 CFR 61.327 - Are there specific endorsement requirements to operate a light-sport aircraft based on VH?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... to operate a light-sport aircraft based on VH? 61.327 Section 61.327 Aeronautics and Space FEDERAL... INSTRUCTORS, AND GROUND INSTRUCTORS Sport Pilots § 61.327 Are there specific endorsement requirements to operate a light-sport aircraft based on VH? (a) Except as specified in paragraph (c) of this section,...

  7. 14 CFR 61.327 - Are there specific endorsement requirements to operate a light-sport aircraft based on VH?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... to operate a light-sport aircraft based on VH? 61.327 Section 61.327 Aeronautics and Space FEDERAL... INSTRUCTORS, AND GROUND INSTRUCTORS Sport Pilots § 61.327 Are there specific endorsement requirements to operate a light-sport aircraft based on VH? (a) Except as specified in paragraph (c) of this section,...

  8. 14 CFR 61.327 - Are there specific endorsement requirements to operate a light-sport aircraft based on VH?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... to operate a light-sport aircraft based on VH? 61.327 Section 61.327 Aeronautics and Space FEDERAL... INSTRUCTORS, AND GROUND INSTRUCTORS Sport Pilots § 61.327 Are there specific endorsement requirements to operate a light-sport aircraft based on VH? (a) Except as specified in paragraph (c) of this section,...

  9. 14 CFR 61.327 - Are there specific endorsement requirements to operate a light-sport aircraft based on VH?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... to operate a light-sport aircraft based on VH? 61.327 Section 61.327 Aeronautics and Space FEDERAL... INSTRUCTORS, AND GROUND INSTRUCTORS Sport Pilots § 61.327 Are there specific endorsement requirements to operate a light-sport aircraft based on VH? (a) Except as specified in paragraph (c) of this section,...

  10. Comparison of improved Aura Tropospheric Emission Spectrometer (TES) CO{sub 2} with HIPPO and SGP aircraft profile measurements

    SciTech Connect

    Kulawik, S. S.; Worden, J. R.; Wofsy, S. C.; Biraud, S. C.; Nassar, R.; Jones, D. B.A.; Olsen, E. T.; Osterman, G. B.

    2012-02-01

    Comparisons are made between mid-tropospheric Tropospheric Emission Spectrometer (TES) carbon dioxide (CO{sub 2}) satellite measurements and ocean profiles from three Hiaper Pole-to-Pole Observations (HIPPO) campaigns and land aircraft profiles from the United States Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site over a 4-yr period. These comparisons are used to characterize the bias in the TES CO{sub 2} estimates and to assess whether calculated and actual uncertainties and sensitivities are consistent. The HIPPO dataset is one of the few datasets spanning the altitude range where TES CO{sub 2} estimates are sensitive, which is especially important for characterization of biases. We find that TES CO{sub 2} estimates capture the seasonal and latitudinal gradients observed by HIPPO CO{sub 2} measurements; actual errors range from 0.8–1.2 ppm, depending on the campaign, and are approximately 1.4 times larger than the predicted errors. The bias of TES versus HIPPO is within 0.85 ppm for each of the 3 campaigns; however several of the sub-tropical TES CO{sub 2} estimates are lower than expected based on the calculated errors. Comparisons of aircraft flask profiles, which are measured from the surface to 5 km, to TES CO{sub 2} at the SGP ARM site show good agreement with an overall bias of 0.1 ppm and rms of 1.0 ppm. We also find that the predicted sensitivity of the TES CO{sub 2} estimates is too high, which results from using a multi-step retrieval for CO{sub 2} and temperature. We find that the averaging kernel in the TES product corrected by a pressure-dependent factor accurately reflects the sensitivity of the TES CO{sub 2} product.

  11. Training aircraft design considerations based on the successive organization of perception in manual control

    NASA Technical Reports Server (NTRS)

    Heffley, R. K.; Clement, W. F.; Craig, S. J.

    1982-01-01

    The thesis that pilot skill development in the Navy approach and landing task is very strongly tied to the aircraft closure rate and, therefore, that pilot training for this task should be based on an appropriate progression closure rate is considered. A rational and explicit determination of design point approach speeds as well as other important aerodynamic features for training aircraft is also considered. Two keys are discussed: recognition of the significance of transitioning from a purely compensatory control loop technique to one involving a pursuit crossfeed between throttle and pitch attitude, and addressing the terminal flight path adjustment in terms of range-to-go.

  12. Fuzzy Model-based Pitch Stabilization and Wing Vibration Suppression of Flexible Wing Aircraft.

    NASA Technical Reports Server (NTRS)

    Ayoubi, Mohammad A.; Swei, Sean Shan-Min; Nguyen, Nhan T.

    2014-01-01

    This paper presents a fuzzy nonlinear controller to regulate the longitudinal dynamics of an aircraft and suppress the bending and torsional vibrations of its flexible wings. The fuzzy controller utilizes full-state feedback with input constraint. First, the Takagi-Sugeno fuzzy linear model is developed which approximates the coupled aeroelastic aircraft model. Then, based on the fuzzy linear model, a fuzzy controller is developed to utilize a full-state feedback and stabilize the system while it satisfies the control input constraint. Linear matrix inequality (LMI) techniques are employed to solve the fuzzy control problem. Finally, the performance of the proposed controller is demonstrated on the NASA Generic Transport Model (GTM).

  13. A CLIPS-based tool for aircraft pilot-vehicle interface design

    NASA Technical Reports Server (NTRS)

    Fowler, Thomas D.; Rogers, Steven P.

    1991-01-01

    The Pilot-Vehicle Interface of modern aircraft is the cognitive, sensory, and psychomotor link between the pilot, the avionics modules, and all other systems on board the aircraft. To assist pilot-vehicle interface designers, a C Language Integrated Production System (CLIPS) based tool was developed that allows design information to be stored in a table that can be modified by rules representing design knowledge. Developed for the Apple Macintosh, the tool allows users without any CLIPS programming experience to form simple rules using a point and click interface.

  14. Phased Acoustic Array Measurements of a 5.75 Percent Hybrid Wing Body Aircraft

    NASA Technical Reports Server (NTRS)

    Burnside, Nathan J.; Horne, William C.; Elmer, Kevin R.; Cheng, Rui; Brusniak, Leon

    2016-01-01

    Detailed acoustic measurements of the noise from the leading-edge Krueger flap of a 5.75 percent Hybrid Wing Body (HWB) aircraft model were recently acquired with a traversing phased microphone array in the AEDC NFAC (Arnold Engineering Development Complex, National Full Scale Aerodynamics Complex) 40- by 80-Foot Wind Tunnel at NASA Ames Research Center. The spatial resolution of the array was sufficient to distinguish between individual support brackets over the full-scale frequency range of 100 to 2875 Hertz. For conditions representative of landing and take-off configuration, the noise from the brackets dominated other sources near the leading edge. Inclusion of flight-like brackets for select conditions highlights the importance of including the correct number of leading-edge high-lift device brackets with sufficient scale and fidelity. These measurements will support the development of new predictive models.

  15. Comparison of Cirrus height and optical depth derived from satellite and aircraft measurements

    SciTech Connect

    Kastner, M.; Kriebel, K.T.; Meerkoetter, R.; Renger, W.; Ruppersberg, G.H.; Wendling, P. )

    1993-10-01

    During the International Cirrus Experiment (ICE'89) simultaneous measurements of cirrus cloud-top height and optical depth by satellite and aircraft have been taken. Data from the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA polar-orbiting meteorological satellite system have been used together with the algorithm package AVHRR processing scheme over clouds, land and ocean (APOLLO) to derive optical depth. NOAA High-Resolution Infrared Radiation Sounder (HIRS) data have been used together with a bispectral technique to derive cloud-top height. Also, the optical depth of some contrails could be estimated. Airborne measurements have been performed simultaneously by using the Airborne Lidar Experiment (ALEX), a backscatter lidar. Comparison of satellite data with airborne data showed agreement of the top heights to about 500 m and of the optical depths to about 30%. These uncertainties are within the limits obtained from error estimates. 34 refs., 8 figs.

  16. Measurement and prediction of noise from low-altitude military aircraft operations

    NASA Astrophysics Data System (ADS)

    Barry, Bernard F.; Payne, Richard C.; Harris, Anthony L.; Weston, Ralph J.

    1992-04-01

    In response to the rapid growth in demand for information on noise levels around military airfields in the UK, NPL developed AIRNOISE, a mathematical model for computing aircraft noise contours. Since its first applications in 1981, the model has been used to determine zones of eligibility within the MoD compensation scheme. The model has been subject to continuous development, e.g., the incorporation of Harrier V/STOL operations. We have now extended the model to include noise from high-speed, low-level operations. The model predicts not only maximum levels but the complete time-history, so that the time-onset rate can be estimated. To aid refinement and validation of the model, a special exercise has been conducted in which Tornado, Harrier, Jaguar, Hawk, F-15 and F-16 aircraft have flown straight and level at heights between about 100 and 400 feet, at various speeds and engine power settings over an array of microphones. This paper describes the trial and the results obtained. The prediction model is outlined and comparisons made between predictions and measurements.

  17. Structural health monitoring methodology for aircraft condition-based maintenance

    NASA Astrophysics Data System (ADS)

    Saniger, Jordi; Reithler, Livier; Guedra-Degeorges, Didier; Takeda, Nobuo; Dupuis, Jean Pierre

    2001-06-01

    Reducing maintenance costs while keeping a constant level of safety is a major issue for Air Forces and airlines. The long term perspective is to implement condition based maintenance to guarantee a constant safety level while decreasing maintenance costs. On this purpose, the development of a generalized Structural Health Monitoring System (SHMS) is needed. The objective of such a system is to localize the damages and to assess their severity, with enough accuracy to allow low cost corrective actions. The present paper describes a SHMS based on acoustic emission technology. This choice was driven by its reliability and wide use in the aerospace industry. The described SHMS uses a new learning methodology which relies on the generation of artificial acoustic emission events on the structure and an acoustic emission sensor network. The calibrated acoustic emission events picked up by the sensors constitute the knowledge set that the system relies on. With this methodology, the anisotropy of composite structures is taken into account, thus avoiding the major cause of errors of classical localization methods. Moreover, it is adaptive to different structures as it does not rely on any particular model but on measured data. The acquired data is processed and the event's location and corrected amplitude are computed. The methodology has been demonstrated and experimental tests on elementary samples presented a degree of accuracy of 1cm.

  18. Crack propagation monitoring in a full-scale aircraft fatigue test based on guided wave-Gaussian mixture model

    NASA Astrophysics Data System (ADS)

    Qiu, Lei; Yuan, Shenfang; Bao, Qiao; Mei, Hanfei; Ren, Yuanqiang

    2016-05-01

    For aerospace application of structural health monitoring (SHM) technology, the problem of reliable damage monitoring under time-varying conditions must be addressed and the SHM technology has to be fully validated on real aircraft structures under realistic load conditions on ground before it can reach the status of flight test. In this paper, the guided wave (GW) based SHM method is applied to a full-scale aircraft fatigue test which is one of the most similar test status to the flight test. To deal with the time-varying problem, a GW-Gaussian mixture model (GW-GMM) is proposed. The probability characteristic of GW features, which is introduced by time-varying conditions is modeled by GW-GMM. The weak cumulative variation trend of the crack propagation, which is mixed in time-varying influence can be tracked by the GW-GMM migration during on-line damage monitoring process. A best match based Kullback-Leibler divergence is proposed to measure the GW-GMM migration degree to reveal the crack propagation. The method is validated in the full-scale aircraft fatigue test. The validation results indicate that the reliable crack propagation monitoring of the left landing gear spar and the right wing panel under realistic load conditions are achieved.

  19. Aerodynamic Measurements of a Gulfstream Aircraft Model With and Without Noise Reduction Concepts

    NASA Technical Reports Server (NTRS)

    Neuhart, Dan H.; Hannon, Judith A.; Khorrami, Mehdi R.

    2014-01-01

    Steady and unsteady aerodynamic measurements of a high-fidelity, semi-span 18% scale Gulfstream aircraft model are presented. The aerodynamic data were collected concurrently with acoustic measurements as part of a larger aeroacoustic study targeting airframe noise associated with main landing gear/flap components, gear-flap interaction noise, and the viability of related noise mitigation technologies. The aeroacoustic tests were conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Wind Tunnel with the facility in the acoustically treated open-wall (jet) mode. Most of the measurements were obtained with the model in landing configuration with the flap deflected at 39º and the main landing gear on and off. Data were acquired at Mach numbers of 0.16, 0.20, and 0.24. Global forces (lift and drag) and extensive steady and unsteady surface pressure measurements were obtained. Comparison of the present results with those acquired during a previous test shows a significant reduction in the lift experienced by the model. The underlying cause was traced to the likely presence of a much thicker boundary layer on the tunnel floor, which was acoustically treated for the present test. The steady and unsteady pressure fields on the flap, particularly in the regions of predominant noise sources such as the inboard and outboard tips, remained unaffected. It is shown that the changes in lift and drag coefficients for model configurations fitted with gear/flap noise abatement technologies fall within the repeatability of the baseline configuration. Therefore, the noise abatement technologies evaluated in this experiment have no detrimental impact on the aerodynamic performance of the aircraft model.

  20. Minimum time acceleration of aircraft turbofan engines by using an algorithm based on nonlinear programming

    NASA Technical Reports Server (NTRS)

    Teren, F.

    1977-01-01

    Minimum time accelerations of aircraft turbofan engines are presented. The calculation of these accelerations was made by using a piecewise linear engine model, and an algorithm based on nonlinear programming. Use of this model and algorithm allows such trajectories to be readily calculated on a digital computer with a minimal expenditure of computer time.

  1. Noise measurements at Stockton Airport obtained during engineering evaluation of two-segment approaches in a 727-222 aircraft

    NASA Technical Reports Server (NTRS)

    Glass, R. E.; Tanner, C. S.

    1973-01-01

    The results of acoustic measurements made on a 727-222 aircraft during standard ILS and two-segment approaches are presented. The aircraft was equipped with a special purpose glide slope computer to provide the capability of making two-segment noise abatement approaches. For upper segment computations, the computer used barometric-corrected pressure altitude and the slant range to a DME transmitter which was colocated with the glide slope transmitter. The computer used the ILS glide slope deviation for lower segment computations. Additional measurements were made on 737 revenue aircraft using the Stockton Airport. The purpose of the acoustical portion of the test was to measure and identify the noise levels during the various approaches.

  2. Retrieval of cloud top height, effective emissivity, and particle size, from aircraft high-spectral-resolution infrared measurements

    NASA Astrophysics Data System (ADS)

    Antonelli, Paolo B.; Ackerman, Steven A.; Menzel, W. Paul; Huang, Hung-Lung; Baum, Bryan A.; Smith, William L.

    2002-02-01

    In this study we compare different approaches to retrieve Cloud Top Height (CTH), Cloud Effective Emissivity (CEE), and the Cloud Particle Size (CPS) from aircraft high-spectral resolution infrared measurements. Two independent methods are used to infer CTH. One approach is based on a high spectral resolution version of the CO2 Slicing algorithm characterized by a statistically based selection of the optimal channel pairs. Another approach the Minimum Local Emissivity Variance algorithm (MLEV) takes advantage of high-resolution observations in the 8-12 micron region to simultaneously derive CTH and CEE. Once CTH has been retrieved a third method, based on the comparison between simulated and observed radiances, is used to infer CPS and CEE. Simulated radiances are computed for 18 microwindows between 8.5 and 12 microns. The cirrus scattering calculations are based on three-dimensional randomly oriented ice columns assuming six different particle size distributions. Multiple scattering calculations are performed for 26 different cloud optical thicknesses (COT) between 0 and 20. The simulated radiances are then compared to the observed radiances to infer COT and CPS for each spectral measurement. We applied these approaches to High-resolution Interferometer Sounder (HIS), National Polar-Orbiting Operational Environmental Satellite System Airborne Sounder Testbed-Interferometer (NAST-I) and Scanning-HIS (S-HIS) data. The preliminary results, consistent between the different algorithms, suggest that the high spectral resolution measurements improve the accuracy of the cloud property retrievals.

  3. A backward modeling study of intercontinental pollution transport using aircraft measurements

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Eckhardt, S.; Spichtinger, N.; Huntrieser, H.; Heland, J.; Schlager, H.; Wilhelm, S.; Arnold, F.; Cooper, O.

    2003-06-01

    In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. Forward calculations of emission tracers from North America, Europe, and Asia were made in order to understand the transport processes. Both episodes were preceded by stagnant conditions over North America, leading to the accumulation of pollutants in the North American boundary layer. Both anthropogenic sources and, to a lesser extent, forest fire emissions contributed to this pollution, which was then exported by warm conveyor belts to the middle and upper troposphere, where it was transported rapidly to Europe. Concentrations of many trace gases (CO, NOy, CO2, acetone, and several volatile organic compounds; O3 in one case) and of ambient atmospheric ions measured aboard the research aircraft were clearly enhanced in the pollution plumes compared to the conditions outside the plumes. Backward simulations with the particle model were introduced as an indispensable tool for a more detailed analysis of the plume's source region. They make trajectory analyses (which, to date, were mainly used to interpret aircraft measurement data) obsolete. Using an emission inventory, we could decompose the tracer mixing ratios at the receptors (i.e., along the flight tracks) into contributions from every grid cell of the inventory. For both plumes we found that emission sources contributing to the tracer concentrations over Europe were distributed over large areas in North America. In one case, sources in California, Texas, and Florida contributed almost equally, and smaller contributions were also made by other sources located between the Yucatan Peninsula and Canada. In the other case, sources in eastern North America

  4. TES carbon monoxide validation with DACOM aircraft measurements during INTEX-B 2006

    NASA Astrophysics Data System (ADS)

    Luo, M.; Rinsland, C.; Fisher, B.; Sachse, G.; Diskin, G.; Logan, J.; Worden, H.; Kulawik, S.; Osterman, G.; Eldering, A.; Herman, R.; Shephard, M.

    2007-12-01

    Validation of Tropospheric Emission Spectrometer (TES) tropospheric CO profiles with in situ CO measurements from the Differential Absorption CO Measurement (DACOM) instrument during the Intercontinental Chemical Transport Experiment (INTEX)-B campaigns in March to May 2006 are presented. For each identified DACOM CO profile, one to three TES CO profiles are selected closest in location to the small area that the DACOM profile covers. The time differences between the comparison profiles are within 2 hours. The DACOM CO vertical profiles are adjusted by applying nearest coincident TES averaging kernels and the a priori profiles. This step accounts for the effect of the vertical resolution of the TES CO retrievals and removes the influence of the a priori assumptions in the comparisons. Comparison statistics for data taken near Houston in March 2006 show good agreement between TES and the adjusted DACOM CO profiles in the lower and middle troposphere with a correlation coefficient of 0.87. On average, the TES CO volume mixing ratio profile is 0-10% lower than the adjusted DACOM CO profile from the lower to middle troposphere. This is within the 10-20% standard deviations of the TES or DACOM CO profiles taken in the Houston area. The comparisons of TES and DACOM CO profiles near Hawaii and Anchorage in April to May 2006 are not as good. In these regions the aircraft DACOM CO profiles are characterized by plumes or enhanced CO layers, consistent with known features in the tracer fields due to transpacific transport of polluted air parcels originating from East Asia. Although TES observations over the Pacific region also show localized regions of enhanced CO, the coincidence criteria for obtaining good comparisons with aircraft measurements are challenging. The meaning of validation comparisons in profile portions where TES retrievals have little sensitivity is addressed. Examinations of characteristic parameters in TES retrievals are important in data applications.

  5. Aircraft measurements of NO and NOy at 12 km over the Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Koike, M.; Kondo, Y.; Makino, Y.; Sugimura, Y.

    1994-01-01

    Measurements of nitric oxide (NO) and total reactive nitrogen (NOy) at altitudes about 12 km were made from two aircraft missions over the central and western Pacific Ocean at latitudes between 65 deg N and 65 deg S during the International Strato-Tropospheric Air Chemistry (INSTAC) program. NO measurements were performed during the first mission in late February and early march 1990, while NOy measurements were performed during the second mission in October 1990. Lowest NO and NOy mixing ratios in the upper troposphere were observed near the equator to be about 30 to approximately 70pptv and 150 to approximately 220pptv, respectively. NOy mixing ratios in the upper troposphere were higher in the northern middle latitude than in the southern middle latitude; 300 to approximately 900pptv in 30 deg N to approximately 50 deg N and 250 to approximately 400pptv around 25 deg S and 50 deg S possibly due to the transport of the polluted air from the boundary layer and the emissions from the commercial aircraft in the northern middle latitudes. Near the equator up to 40 deg S, the NO values showed very high variability and reached between 200 and 2000 pptv. NOy(pptv)/ozone(ppbv) ratios in the upper troposphere were between about 3 and 20 and these values seem to be higher in the lower latitude except for the polluted air in the northern middle latitude. These NOy/ozone ratios in the equatorial upper troposphere are higher than those in the lower stratosphere observed by others. These features of NO and NOy in the equatorial upper troposphere suggest that NOx is produced possibly by the lightning.

  6. A study of Asian dust plumes using satellite, surface, and aircraft measurements during the INTEX-B field experiment

    NASA Astrophysics Data System (ADS)

    Logan, Timothy; Xi, Baike; Dong, Xiquan; Obrecht, Rebecca; Li, Zhanqing; Cribb, Maureen

    2010-04-01

    Asian dust events occur frequently during the boreal spring season. Their optical properties have been analyzed by using a combination of source region (ground-based and satellite) and remote Pacific Ocean (aircraft) measurements during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B) field campaign which lasted from 7 April to 15 May 2006. A strong dust event originating from the Gobi Desert and passing over the Xianghe surface site on 17 April 2006 has been extensively analyzed. The surface averaged aerosol optical depth (AOD) values increased from 0.17 (clear sky) to 4.0 (strong dust), and the Angström exponent (α) dropped from 1.26 (clear sky) to below 0.1. Its total downwelling SW flux over the Xianghe site (thousands of kilometers away from the dust source region) is only 46% of the clear-sky value with almost no direct transmission and nearly double the diffuse SW clear-sky value. This event was also captured 6 days later by satellite observations as well as the UND/NASA DC-8 aircraft over the eastern Pacific Ocean. The DC-8 measurements in the remote Pacific region further classified the plumes into dust dominant, pollution dominant, and a mixture of dust and pollution events. HYSPLIT backward trajectories not only verified the origins of each case we selected but also showed (1) two possible origins for the dust: the Gobi and Taklimakan deserts; and (2) pollution: urban areas in eastern China, Japan, and other industrialized cities east of the two deserts. Based on the averaged satellite retrieved AOD data (0.5° × 0.5° grid box), declining AOD values with respect to longitude demonstrated the evolution of the transpacific transport pathway of Asian dust and pollution over the period of the field campaign.

  7. ACSYNT - A standards-based system for parametric, computer aided conceptual design of aircraft

    NASA Technical Reports Server (NTRS)

    Jayaram, S.; Myklebust, A.; Gelhausen, P.

    1992-01-01

    A group of eight US aerospace companies together with several NASA and NAVY centers, led by NASA Ames Systems Analysis Branch, and Virginia Tech's CAD Laboratory agreed, through the assistance of Americal Technology Initiative, in 1990 to form the ACSYNT (Aircraft Synthesis) Institute. The Institute is supported by a Joint Sponsored Research Agreement to continue the research and development in computer aided conceptual design of aircraft initiated by NASA Ames Research Center and Virginia Tech's CAD Laboratory. The result of this collaboration, a feature-based, parametric computer aided aircraft conceptual design code called ACSYNT, is described. The code is based on analysis routines begun at NASA Ames in the early 1970's. ACSYNT's CAD system is based entirely on the ISO standard Programmer's Hierarchical Interactive Graphics System and is graphics-device independent. The code includes a highly interactive graphical user interface, automatically generated Hermite and B-Spline surface models, and shaded image displays. Numerous features to enhance aircraft conceptual design are described.

  8. Suppressor nozzle and airframe noise measurements during flyover of a modified F106B aircraft with underwing nacelles

    NASA Technical Reports Server (NTRS)

    Burley, R. R.

    1974-01-01

    The effect of flight velocity on the jet noise and thrust of a 104-tube suppressor nozzle was investigated using an F-106B delta wing aircraft modified to carry two underwing nacelles each containing a turbojet engine. The nozzle was mounted behind one of the nacelles. Flight velocity had a large adverse effect on thrust and a small adverse effect on suppression when correlated with relative jet velocity. The clean airframe noise of the aircraft was measured at Mach 0.4 and was compared with that predicted from an empirical expression. The 83 db measured value was considerably below the predicted value.

  9. Calibration of 3-D wind measurements on a single-engine research aircraft

    NASA Astrophysics Data System (ADS)

    Mallaun, C.; Giez, A.; Baumann, R.

    2015-08-01

    An innovative calibration method for the wind speed measurement using a boom-mounted Rosemount model 858 AJ air velocity probe is introduced. The method is demonstrated for a sensor system installed on a medium-size research aircraft which is used for measurements in the atmospheric boundary layer. The method encounters a series of coordinated flight manoeuvres to directly estimate the aerodynamic influences on the probe and to calculate the measurement uncertainties. The introduction of a differential Global Positioning System (DGPS) combined with a high-accuracy inertial reference system (IRS) has brought major advances to airborne measurement techniques. The exact determination of geometrical height allows the use of the pressure signal as an independent parameter. Furthermore, the exact height information and the stepwise calibration process lead to maximum accuracy. The results show a measurement uncertainty for the aerodynamic influence of the dynamic and static pressures of 0.1 hPa. The applied parametrisation does not require any height dependencies or time shifts. After extensive flight tests a correction for the flow angles (attack and sideslip angles) was found, which is necessary for a successful wind calculation. A new method is demonstrated to correct for the aerodynamic influence on the sideslip angle. For the three-dimensional (3-D) wind vector (with 100 Hz resolution) a novel error propagation scheme is tested, which determines the measurement uncertainties to be 0.3 m s-1 for the horizontal and 0.2 m s-1 for the vertical wind components.

  10. Calibration of 3-D wind measurements on a single engine research aircraft

    NASA Astrophysics Data System (ADS)

    Mallaun, C.; Giez, A.; Baumann, R.

    2015-02-01

    An innovative calibration method for the wind speed measurement using a boom mounted Rosemount model 858 AJ air velocity probe is introduced. The method is demonstrated for a sensor system installed on a medium size research aircraft which is used for measurements in the atmospheric boundary layer. The method encounters a series of coordinated flight manoeuvres to directly estimate the aerodynamic influences on the probe and to calculate the measurement uncertainties. The introduction of a differential Global Positioning System (DGPS) combined with a high accuracy Inertial Reference System (IRS) has brought major advances to airborne measurement techniques. The exact determination of geometrical height allows the use of the pressure signal as an independent parameter. Furthermore, the exact height information and the stepwise calibration process lead to maximum accuracy. The results show a measurement uncertainty for the aerodynamic influence of the dynamic and static pressures of 0.1 hPa. The applied parametrisation does not require any height dependencies or time shifts. After extensive flight tests a correction for the flow angles (attack and sideslip angles) was found, which is necessary for a successful wind calculation. A new method is demonstrated to correct for the aerodynamic influence on the sideslip angle. For the 3-D wind vector (with 100 Hz resolution) a novel error propagation scheme is tested, which determines the measurement uncertainties to be 0.3 m s-1 for the horizontal and 0.2 m s-1 for the vertical wind components.

  11. Polarimetric measurements of sea surface brightness temperatures using an aircraft K-band radiometer

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Wilson, William J.; Li, Fuk K.; Nghiem, Son V.; Ricketts, William B.

    1995-01-01

    This paper presents the first experimental evidence that the polarimetric brightness temperatures of sea surfaces are sensitive to ocean wind direction in the incidence angle range of 30 to 50 degrees. Our experimental data were collected by a K-band (19.35 GHz) polarimetric wind radiometer (WINDRAD) mounted on the NASA DC-8 aircraft. A set of aircraft radiometer flights was successfully completed in November 1993. We performed circle flights over National Data Buoy Center (NDBC) moored buoys deployed off the northern California coast, which provided ocean wind measurements. The first WINDRAD flight was made on November 4, 1993. There was clear weather with a wind speed of 12 m/s at 330 degrees around the Pt. Arena buoy. We circled the buoy at three incidence angles, and all data when plotted as functions of azimuth angles show clear modulations of several Kelvin. At 40 degrees incidence angle, there is a 5 Kelvin peak-to-peak signal in the second Stokes parameter Q and the third Stokes parameter U. The Q data maximum is in the upwind direction and U has a 45 degrees phase shift in azimuth as predicted by theory. There is also an up/downwind asymmetry of 2 Kelvin in the Q data, and 1 Kelvin in the U data. At 50 degrees incidence angle, the collected data show very similar wind direction signatures to the SSM/I model function. Additional flights were made on other days under cloudy conditions. Data taken at a wind speed of 8 m/s show that at 40 degrees incidence Q and U have a smaller azimuthal modulation of 3 Kelvin, probably due to the lower wind speed. Additionally, the simultaneously recorded video images of sea surfaces suggested that Q and U data were less sensitive to unpolarized geophysical variations, such as clouds and whitecaps, while the T(v) and T(h) increased by a few Kelvin when the radiometer beam crossed over clouds, or there was a sudden increase of whitecaps in the radiometer footprint. The results of our aircraft flights indicate that passive

  12. Aircraft Measurements of Temperature and Liquid Water Content in Entrainment Interface Layer of Stratocumulus Clouds.

    NASA Astrophysics Data System (ADS)

    Haman, K. E.; Gerber, H.; Kumala, W.; Malinowski, S. P.

    2009-09-01

    Entrainment of dry, warm air from above the cloud and its mixing with the colder cloudy air is an important process in dynamics of inversion topped stratocumulus, leading to formation of a transition layer of complex structure - Entrainment Interface Layer (EIL). It consists of mutual filaments if cloudy and clear air of various thickness at different stages of stirring, mixing and homogenization. Borders between these filaments are often very sharp, with temperature jumps of few kelvins and liquid water content (LWC) jumps of up to 0.5 gmE-3 over distance of few centimeters, which cannot be resolved by means of standard aircraft instrumentation. This layer is an area of various specific dynamic and thermodynamic phenomena; in particular it is a source of downdrafts penetrating the cloud as the so called "cloud holes". Small scale structure of EIL has been investigated in 2001 during DYCOMS II campaign in marine stratocumulus over Eastern Pacific, by means of Ultrafast Aircraft Thermometer (UFT-F) from University of Warsaw and PVM-100A LWC-meter from Gerber Scientific, Inc. Some results of this research has been published in 2007 in Quarterly Journal of RMS. UFT-F has a thermoresistive sensing element protected against impact of cloud droplets and response time constant of order 10E-4s. PVM-100A is an optical instrument and has spatial resolution of order 10 cm. For recording a sampling rate of 1kHz has been typically applied with 10 kHz (for UFT-F only) on selected fragments of flights. Unfortunately, for some technical reasons, these two instruments, installed on the NCAR C-130 aircraft, were separated by about 6 meters what limited possibilities and precision of comparing their indications. There were also some failures during the flights due to which many potentially interesting measurements and observations have been lost. Opportunity to get improved observations of EIL appeared in 2008 at POST (Physics of Stratocumulus Top) Project. During POST a number of

  13. Analysis of vibration induced error in turbulence velocity measurements from an aircraft wing tip boom

    NASA Technical Reports Server (NTRS)

    Akkari, S. H.; Frost, W.

    1982-01-01

    The effect of rolling motion of a wing on the magnitude of error induced due to the wing vibration when measuring atmospheric turbulence with a wind probe mounted on the wing tip was investigated. The wing considered had characteristics similar to that of a B-57 Cambera aircraft, and Von Karman's cross spectrum function was used to estimate the cross-correlation of atmospheric turbulence. Although the error calculated was found to be less than that calculated when only elastic bendings and vertical motions of the wing are considered, it is still relatively large in the frequency's range close to the natural frequencies of the wing. Therefore, it is concluded that accelerometers mounted on the wing tip are needed to correct for this error, or the atmospheric velocity data must be appropriately filtered.

  14. Probing emissions of military cargo aircraft: description of a joint field measurement Strategic Environmental Research and Development Program.

    PubMed

    Cheng, Meng-Dawn; Corporan, Edwin; DeWitt, Matthew J; Spicer, Chester W; Holdren, Michael W; Cowen, Kenneth A; Laskin, Alex; Harris, David B; Shores, Richard C; Kagann, Robert; Hashmonay, Ram

    2008-06-01

    To develop effective air quality control strategies for military air bases, there is a need to accurately quantify these emissions. In support of the Strategic Environmental Research and Development Program project, the particulate matter (PM) and gaseous emissions from two T56 engines on a parked C-130 aircraft were characterized at the Kentucky Air National Guard base in Louisville, KY. Conventional and research-grade instrumentation and methodology were used in the field campaign during the first week of October 2005. Particulate emissions were sampled at the engine exit plane and at 15 m downstream. In addition, remote sensing of the gaseous species was performed via spectroscopic techniques at 5 and 15 m downstream of the engine exit. It was found that PM mass and number concentrations measured at 15-m downstream locations, after dilution-correction generally agreed well with those measured at the engine exhaust plane; however, higher variations were observed in the far-field after natural dilution of the downstream measurements was accounted for. Using carbon dioxide-normalized data we demonstrated that gas species measurements by extractive and remote sensing techniques agreed reasonably well.

  15. Video-based cargo fire verification system with fuzzy inference engine for commercial aircraft

    NASA Astrophysics Data System (ADS)

    Sadok, Mokhtar; Zakrzewski, Radek; Zeliff, Bob

    2005-02-01

    Conventional smoke detection systems currently installed onboard aircraft are often subject to high rates of false alarms. Under current procedures, whenever an alarm is issued the pilot is obliged to release fire extinguishers and to divert to the nearest airport. Aircraft diversions are costly and dangerous in some situations. A reliable detection system that minimizes false-alarm rate and allows continuous monitoring of cargo compartments is highly desirable. A video-based system has been recently developed by Goodrich Corporation to address this problem. The Cargo Fire Verification System (CFVS) is a multi camera system designed to provide live stream video to the cockpit crew and to perform hotspot, fire, and smoke detection in aircraft cargo bays. In addition to video frames, the CFVS uses other sensor readings to discriminate between genuine events such as fire or smoke and nuisance alarms such as fog or dust. A Mamdani-type fuzzy inference engine is developed to provide approximate reasoning for decision making. In one implementation, Gaussian membership functions for frame intensity-based features, relative humidity, and temperature are constructed using experimental data to form the system inference engine. The CFVS performed better than conventional aircraft smoke detectors in all standardized tests.

  16. The effects of aircraft noise at Williams Air Force Base Auxiliary Field on residential property values

    SciTech Connect

    Morey, M.J.

    1990-11-01

    This report considers the environmental consequences of moving the flight training operations of the US Air Force's 82nd Flying Training Wing from the auxiliary airfield, Coolidge-Florence Municipal Airport (CFMA), to a more remote location in Pinal County, Arizona. It examines how actual noise from touch-and-go flights of T-37 aircraft and perceived (anticipated) noise affect the market value of residential property near CFMA. Noise, measured by a noise index, is correlated with market values through a regression analysis applied to a hedonic price model of the Coolidge-Florence housing market. Prices and characteristics of 42 residential properties sold in 1987 and 1988 were used to estimate a perceived noise effect. The report finds that the coefficient on the measure of perceived noise, based on the noise exposure forecast (NEF) index, is statistically insignificant, even though the sign and value are consistent with those estimated in other studies. It concludes that current flights do not have a significant effect on residential property values, partially because there is no housing near CFMA. This and larger studies indicate that flight operations at a new auxiliary airfield would not affect property values if runways were at least 12,000 feet away from housing. 12 refs., 2 tabs.

  17. Measuring subjective response to aircraft noise: the effects of survey context.

    PubMed

    Kroesen, Maarten; Molin, Eric J E; van Wee, Bert

    2013-01-01

    In applied research, noise annoyance is often used as indicator of subjective reaction to aircraft noise in residential areas. The present study aims to show that the meaning which respondents attach to the concept of aircraft noise annoyance is partly a function of survey context. To this purpose a survey is conducted among residents living near Schiphol Airport, the largest airport in the Netherlands. In line with the formulated hypotheses it is shown that different sets of preceding questionnaire items influence the response distribution of aircraft noise annoyance as well as the correlational patterns between aircraft noise annoyance and other relevant scales.

  18. Comparison of Measured and Block Structured Simulations for the F-16XL Aircraft

    NASA Technical Reports Server (NTRS)

    Boelens, O. J.; Badcock, K. J.; Elmilgui, A.; Abdol-Hamid, K. S.; Massey, S. J.

    2008-01-01

    This article presents a comparison of the predictions of three RANS codes for flight conditions of the F-16XL aircraft which feature vortical flow. The three codes, ENSOLV, PMB and PAB3D, solve on structured multi-block grids. Flight data for comparison was available in the form of surface pressures, skin friction, boundary layer data and photographs of tufts. The three codes provided predictions which were consistent with expectations based on the turbulence modelling used, which was k- , k- with vortex corrections and an Algebraic Stress Model. The agreement with flight data was good, with the exception of the outer wing primary vortex strength. The confidence in the application of the CFD codes to complex fighter configurations increased significantly through this study.

  19. Aircraft measurements of nitrogen dioxide and peroxyacetyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Steele, H.D.; Drayton, P.J.; Hubbe, J.M.

    1999-10-01

    Fast capillary gas chromatography with luminol detection has been used to make airborne measurements of nitrogen dioxide (NO{sub 2}) and peroxyacetyl nitrate (PAN). The analysis system allows for the simultaneous measurement of NO{sub 2} and peroxyacyl nitrates (PANs) with time resolution of less than 1 min, and improvement of a factor of 4--5 over previously reported methods using electron capture detection. Data presented were taken near Pasco, Washington, in August 1997, during a test flight onboard the US Department of Energy G-1 aircraft. The authors report measurements of NO{sub 2} in the boundary layer in a paper mill plume and a plume from a grass fire, in addition to analyses for free tropospheric NO{sub 2} and PAN. Ratios of PAN/NO{sub 2} were observed to increase with altitude (decreasing temperature) and to reach values of 2--4 above the boundary layer, consistent with the thermal equilibrium of the peroxyacetyl radical and NO{sub 2} and PAN. Estimates for the peroxyacetyl radical in the continental free troposphere, calculated from this equilibrium, were found to be in the range of 10{sup 4}--10{sup 5} molecules per cubic centimeter. These results demonstrate the application of this approach for airborne measurements of NO{sub 2} and PAN in a wide range of field study scenarios.

  20. Aerosol Forcing During INDOEX and ACE-Asia as Determined From Aircraft and Grou nd Measurements

    NASA Astrophysics Data System (ADS)

    Marsden, D. C.; Valero, F. P.; Bush, B. C.; Pope, S. K.; Leitner, A. S.

    2002-12-01

    A suite of radiometers was flown on the NCAR C-130 aircraft throughout the INDOEX and ACE-Asia experiments to measure broadband and spectral irradiances. Identical instruments were placed in the zenith and nadir positions, allowing net flux and optical depth to be determined. The radiative forcing efficiency (aerosol forcing per unit optical depth) was determined below the aerosol layer, i.e. at an altitude of about 40 meters. This was measured in the spectral range s 220 to 3910 nm (total solar forcing) and 680 to 3300 nm (near infrared) and in seven spectral channels covering contiguously the visible range from 400 to 700 nm. Surface measurements of solar insolation as well as aerosol column optical depth were made at Kaashidoo, Maldives (INDOEX) and at Cheju Island, South Korea (ACE-Asia). These measurements, in conjunction with aerosol-free model simulations, are used to determine the radiative forcing at the surface for the visible, near-infrared, and total solar spectral bandpasses. During INDOEX the diurnally averaged broadband surface aerosol radiative forcing was -72.2+/- 5.5 W m-2 per unit optical depth at 500 nm with roughly half being contributed from the visible (-38.5+/- 4.0 W m-2). The corresponding results during ACE-Asia were: broadband -73.1+/- 9.7 W m-2, visible -41.7+/- 4.7 W m-2, and near infrared -36.3+/- -5.6 W m-2.

  1. Description of an aircraft lightning and simulated nuclear electromagnetic pulse (NEMP) threat based on experimental data

    NASA Technical Reports Server (NTRS)

    Rustan, Pedro L., Jr.

    1987-01-01

    Lightning data obtained by measuring the surface electromagnetic fields on a CV-580 research aircraft during 48 lightning strikes between 1500 and 18,000 feet in central Florida during the summers of 1984 and 1985, and nuclear electromagnetic pulse (NEMP) data obtained by surface electromagnetic field measurements using a 1:74 CV-580 scale model, are presented. From one lightning event, maximum values of 3750 T/s for the time rate of change of the surface magnetic flux density, and 4.7 kA for the peak current, were obtained. From the simulated NEMP test, maximum values of 40,000 T/s for the time rate of change of the surface magnetic flux density, and 90 A/sq m for the total normal current density, were found. The data have application to the development of a military aircraft lightning/NEMP standard.

  2. Extending acoustic data measured with small-scale supersonic model jets to practical aircraft exhaust jets

    NASA Astrophysics Data System (ADS)

    Kuo, Ching-Wen

    2010-06-01

    Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions within the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania State University and the NASA Glenn Research Center, in partnership with GE Aviation, is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles. An equally important objective is to develop a scaling methodology for using data obtained from small- and moderate-scale experiments which exhibits the independence of the jet sizes to the measured noise levels. The experimental results presented in this thesis have shown reasonable agreement between small-scale and moderate-scale jet acoustic data, as well as between heated jets and heat-simulated ones. As the scaling methodology is validated, it will be extended to using acoustic data measured with small-scale supersonic model jets to the prediction of the most important components of full-scale engine noise. When comparing the measured acoustic spectra with a microphone array set at different radial locations, the characteristics of the jet noise source distribution may induce subtle inaccuracies, depending on the conditions of jet operation. A close look is taken at the details of the noise generation region in order to better understand the mismatch between spectra measured at various acoustic field radial locations. A processing methodology was developed to correct the effect of the noise source distribution and efficiently compare near-field and far-field spectra with unprecedented accuracy. This technique then demonstrates that the measured noise levels in the physically restricted space of an anechoic chamber can be appropriately

  3. USE OF REMPI-TOFMS FOR REAL-TIME MEASUREMENT OF TRACE AROMATICS DURING OPERATION OF AIRCRAFT GROUND EQUIPMENT

    EPA Science Inventory

    Emissions of aromatic air toxics from aircraft ground equipment were measured with a resonance enhanced multiphoton ionization—time of flight mass spectrometry (REMPI-TOFMS) system consisting of a pulsed solid state laser for photoionization and a TOFMS for mass discrimination. T...

  4. Volume-imaging lidar observations of the convective structure surrounding the flight path of a flux-measuring aircraft

    NASA Technical Reports Server (NTRS)

    Eloranta, Edwin W.; Forrest, Daniel K.

    1992-01-01

    The University of Wisconsin volume imaging lidar has been used to portray images of the three-dimensional structure of clear air convective plumes in the atmosphere surrounding the flight path of the instrumented Twin Otter aircraft operated by the National Aeronautical Establishment of Canada. Lidar images provide a context for interpretation of the aircraft measurements. The position of data points within a convective element can be determined and the temporal development of the plume can be observed to time the observation with respect to the life cycle of the plume. Plots of the vertical flux of water vapor, superimposed on lidar images clearly demonstrate the well-known sampling difficulties encountered when attempting to measure fluxes near the top of the convective layer. When loran was used to determine average aircraft velocity, flight-leg-averaged horizontal winds measured by the aircraft and area-averaged winds measured by lidar agree to within 0.2 m/s in speed and 1 deg in direction.

  5. Interior and exterior fuselage noise measured on NASA's C-8a augmentor wing jet-STOL research aircraft

    NASA Technical Reports Server (NTRS)

    Shovlin, M. D.

    1977-01-01

    Interior and exterior fuselage noise levels were measured on NASA's C-8A Augmentor Wing Jet-STOL Research Aircraft in order to provide design information for the Quiet Short-Haul Research Aircraft (QSRA), which will use a modified C-8A fuselage. The noise field was mapped by 11 microphones located internally and externally in three areas: mid-fuselage, aft fuselage, and on the flight deck. Noise levels were recorded at four power settings varying from takeoff to flight idle and were plotted in one-third octave band spectra. The overall sound pressure levels of the external noise field were compared to previous tests and found to correlate well with engine primary thrust levels. Fuselage values were 145 + or - 3 dB over the aircraft's normal STOL operating range.

  6. Adaptive Data-based Predictive Control for Short Take-off and Landing (STOL) Aircraft

    NASA Technical Reports Server (NTRS)

    Barlow, Jonathan Spencer; Acosta, Diana Michelle; Phan, Minh Q.

    2010-01-01

    Data-based Predictive Control is an emerging control method that stems from Model Predictive Control (MPC). MPC computes current control action based on a prediction of the system output a number of time steps into the future and is generally derived from a known model of the system. Data-based predictive control has the advantage of deriving predictive models and controller gains from input-output data. Thus, a controller can be designed from the outputs of complex simulation code or a physical system where no explicit model exists. If the output data happens to be corrupted by periodic disturbances, the designed controller will also have the built-in ability to reject these disturbances without the need to know them. When data-based predictive control is implemented online, it becomes a version of adaptive control. The characteristics of adaptive data-based predictive control are particularly appropriate for the control of nonlinear and time-varying systems, such as Short Take-off and Landing (STOL) aircraft. STOL is a capability of interest to NASA because conceptual Cruise Efficient Short Take-off and Landing (CESTOL) transport aircraft offer the ability to reduce congestion in the terminal area by utilizing existing shorter runways at airports, as well as to lower community noise by flying steep approach and climb-out patterns that reduce the noise footprint of the aircraft. In this study, adaptive data-based predictive control is implemented as an integrated flight-propulsion controller for the outer-loop control of a CESTOL-type aircraft. Results show that the controller successfully tracks velocity while attempting to maintain a constant flight path angle, using longitudinal command, thrust and flap setting as the control inputs.

  7. Design and evaluation of a wireless sensor network based aircraft strength testing system.

    PubMed

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system. PMID:22408521

  8. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-01

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking. PMID:26730457

  9. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-01

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking.

  10. Aircraft Operations Classification System

    NASA Technical Reports Server (NTRS)

    Harlow, Charles; Zhu, Weihong

    2001-01-01

    Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.

  11. Impact imaging of aircraft composite structure based on a model-independent spatial-wavenumber filter.

    PubMed

    Qiu, Lei; Liu, Bin; Yuan, Shenfang; Su, Zhongqing

    2016-01-01

    The spatial-wavenumber filtering technique is an effective approach to distinguish the propagating direction and wave mode of Lamb wave in spatial-wavenumber domain. Therefore, it has been gradually studied for damage evaluation in recent years. But for on-line impact monitoring in practical application, the main problem is how to realize the spatial-wavenumber filtering of impact signal when the wavenumber of high spatial resolution cannot be measured or the accurate wavenumber curve cannot be modeled. In this paper, a new model-independent spatial-wavenumber filter based impact imaging method is proposed. In this method, a 2D cross-shaped array constructed by two linear piezoelectric (PZT) sensor arrays is used to acquire impact signal on-line. The continuous complex Shannon wavelet transform is adopted to extract the frequency narrowband signals from the frequency wideband impact response signals of the PZT sensors. A model-independent spatial-wavenumber filter is designed based on the spatial-wavenumber filtering technique. Based on the designed filter, a wavenumber searching and best match mechanism is proposed to implement the spatial-wavenumber filtering of the frequency narrowband signals without modeling, which can be used to obtain a wavenumber-time image of the impact relative to a linear PZT sensor array. By using the two wavenumber-time images of the 2D cross-shaped array, the impact direction can be estimated without blind angle. The impact distance relative to the 2D cross-shaped array can be calculated by using the difference of time-of-flight between the frequency narrowband signals of two different central frequencies and the corresponding group velocities. The validations performed on a carbon fiber composite laminate plate and an aircraft composite oil tank show a good impact localization accuracy of the model-independent spatial-wavenumber filter based impact imaging method.

  12. Impact imaging of aircraft composite structure based on a model-independent spatial-wavenumber filter.

    PubMed

    Qiu, Lei; Liu, Bin; Yuan, Shenfang; Su, Zhongqing

    2016-01-01

    The spatial-wavenumber filtering technique is an effective approach to distinguish the propagating direction and wave mode of Lamb wave in spatial-wavenumber domain. Therefore, it has been gradually studied for damage evaluation in recent years. But for on-line impact monitoring in practical application, the main problem is how to realize the spatial-wavenumber filtering of impact signal when the wavenumber of high spatial resolution cannot be measured or the accurate wavenumber curve cannot be modeled. In this paper, a new model-independent spatial-wavenumber filter based impact imaging method is proposed. In this method, a 2D cross-shaped array constructed by two linear piezoelectric (PZT) sensor arrays is used to acquire impact signal on-line. The continuous complex Shannon wavelet transform is adopted to extract the frequency narrowband signals from the frequency wideband impact response signals of the PZT sensors. A model-independent spatial-wavenumber filter is designed based on the spatial-wavenumber filtering technique. Based on the designed filter, a wavenumber searching and best match mechanism is proposed to implement the spatial-wavenumber filtering of the frequency narrowband signals without modeling, which can be used to obtain a wavenumber-time image of the impact relative to a linear PZT sensor array. By using the two wavenumber-time images of the 2D cross-shaped array, the impact direction can be estimated without blind angle. The impact distance relative to the 2D cross-shaped array can be calculated by using the difference of time-of-flight between the frequency narrowband signals of two different central frequencies and the corresponding group velocities. The validations performed on a carbon fiber composite laminate plate and an aircraft composite oil tank show a good impact localization accuracy of the model-independent spatial-wavenumber filter based impact imaging method. PMID:26253754

  13. A laser-induced fluorescence instrument for aircraft measurements of sulfur dioxide in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Rollins, Andrew W.; Thornberry, Troy D.; Ciciora, Steven J.; McLaughlin, Richard J.; Watts, Laurel A.; Hanisco, Thomas F.; Baumann, Esther; Giorgetta, Fabrizio R.; Bui, Thaopaul V.; Fahey, David W.; Gao, Ru-Shan

    2016-09-01

    This work describes the development and testing of a new instrument for in situ measurements of sulfur dioxide (SO2) on airborne platforms in the upper troposphere and lower stratosphere (UT-LS). The instrument is based on the laser-induced fluorescence technique and uses the fifth harmonic of a tunable fiber-amplified semiconductor diode laser system at 1084.5 nm to excite SO2 at 216.9 nm. Sensitivity and background checks are achieved in flight by additions of SO2 calibration gas and zero air, respectively. Aircraft demonstration was performed during the NASA Volcano-Plume Investigation Readiness and Gas-Phase and Aerosol Sulfur (VIRGAS) experiment, which was a series of flights using the NASA WB-57F during October 2015 based at Ellington Field and Harlingen, Texas. During these flights, the instrument successfully measured SO2 in the UT-LS at background (non-volcanic) conditions with a precision of 2 ppt at 10 s and an overall uncertainty determined primarily by instrument drifts of ±(16 % + 0.9 ppt).

  14. Morphing Wing Weight Predictors and Their Application in a Template-Based Morphing Aircraft Sizing Environment II. Part 2; Morphing Aircraft Sizing via Multi-level Optimization

    NASA Technical Reports Server (NTRS)

    Skillen, Michael D.; Crossley, William A.

    2008-01-01

    This report presents an approach for sizing of a morphing aircraft based upon a multi-level design optimization approach. For this effort, a morphing wing is one whose planform can make significant shape changes in flight - increasing wing area by 50% or more from the lowest possible area, changing sweep 30 or more, and/or increasing aspect ratio by as much as 200% from the lowest possible value. The top-level optimization problem seeks to minimize the gross weight of the aircraft by determining a set of "baseline" variables - these are common aircraft sizing variables, along with a set of "morphing limit" variables - these describe the maximum shape change for a particular morphing strategy. The sub-level optimization problems represent each segment in the morphing aircraft's design mission; here, each sub-level optimizer minimizes fuel consumed during each mission segment by changing the wing planform within the bounds set by the baseline and morphing limit variables from the top-level problem.

  15. Aircraft measurements of nitrogen dioxide and peroxyacyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Drayton, P.J.

    1997-09-01

    Peroxyacyl nitrates (PANs) and nitrogen dioxide (NO{sub 2}) are important trace gas species associated with photochemical air pollution. The PANs are in thermal equilibrium with the peroxyacetyl radical and NO{sub 2}. Because PANs are trapped peroxy radicals, they are an important indicator species of the photochemical age of an air parcel, as well as being a means of long-range transporting of NO{sub 2}, leading to the formation of regional ozone and other oxidants. Typically, PANs are measured by using a gas chromatograph with electron-capture detection (ECD). Once automated, this method has been shown to be reliable and quite sensitive, allowing the levels of PANs to be measured at low parts per trillion in the troposphere. Unfortunately, a number of other atmospheric gases also have strong ECD signals or act as inferences and limit the speed in which the analysis can be completed. Currently, the shortest analysis time for PAN is approx. 5 minutes with ECD. The authors recent examined the luminol detection of NO{sub 2} and PANs using gas capillary chromatography for rapid monitoring of these important trace gases. Analysis of the PANs (PAN, PPN, and PBN) and NO{sub 2} in one minute has been demonstrated in laboratory studies by using this approach. Reported here are modifications of this instrument for aircraft operation and preliminary results from test flights taken near Pasco, Washington in August of 1997.

  16. Aeroacoustic Study of a High-Fidelity Aircraft Model: Part 1- Steady Aerodynamic Measurements

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Hannon, Judith A.; Neuhart, Danny H.; Markowski, Gregory A.; VandeVen, Thomas

    2012-01-01

    In this paper, we present steady aerodynamic measurements for an 18% scale model of a Gulfstream air-craft. The high fidelity and highly-instrumented semi-span model was developed to perform detailed aeroacoustic studies of airframe noise associated with main landing gear/flap components and gear-flap interaction noise, as well as to evaluate novel noise reduction concepts. The aeroacoustic tests, being conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel, are split into two entries. The first entry, completed November 2010, was entirely devoted to the detailed mapping of the aerodynamic characteristics of the fabricated model. Flap deflections of 39?, 20?, and 0? with the main landing gear on and off were tested at Mach numbers of 0.16, 0.20, and 0.24. Additionally, for each flap deflection, the model was tested with the tunnel both in the closed-wall and open-wall (jet) modes. During this first entry, global forces (lift and drag) and extensive steady and unsteady surface pressure measurements were obtained. Preliminary analysis of the measured forces indicates that lift, drag, and stall characteristics compare favorably with Gulfstream?s high Reynolds number flight data. The favorable comparison between wind-tunnel and flight data allows the semi-span model to be used as a test bed for developing/evaluating airframe noise reduction concepts under a relevant environment. Moreover, initial comparison of the aerodynamic measurements obtained with the tunnel in the closed- and open-wall configurations shows similar aerodynamic behavior. This permits the acoustic and off-surface flow measurements, planned for the second entry, to be conducted with the tunnel in the open-jet mode.

  17. Artificial intelligence (AI) based tactical guidance for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Mcmanus, John W.; Goodrich, Kenneth H.

    1990-01-01

    A research program investigating the use of artificial intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS), a second generation TDG, is presented. The knowledge-based systems used by CLAWS to aid in the tactical decision-making process are outlined in detail, and the results of tests to evaluate the performance of CLAWS versus a baseline TDG developed in FORTRAN to run in real time in the Langley Differential Maneuvering Simulator, are presented. To date, these test results have shown significant performance gains with respect to the TDG baseline in one-versus-one air combat engagements, and the AI-based TDG software has proven to be much easier to modify and maintain than the baseline FORTRAN TDG programs.

  18. Fault Diagnosis for the Heat Exchanger of the Aircraft Environmental Control System Based on the Strong Tracking Filter

    PubMed Central

    Ma, Jian; Lu, Chen; Liu, Hongmei

    2015-01-01

    The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system’s efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger. PMID:25823010

  19. Fault diagnosis for the heat exchanger of the aircraft environmental control system based on the strong tracking filter.

    PubMed

    Ma, Jian; Lu, Chen; Liu, Hongmei

    2015-01-01

    The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.

  20. Fault diagnosis for the heat exchanger of the aircraft environmental control system based on the strong tracking filter.

    PubMed

    Ma, Jian; Lu, Chen; Liu, Hongmei

    2015-01-01

    The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger. PMID:25823010

  1. In situ ozone measurements within the 1987 Antarctic ozone hole from a high-altitude ER-2 aircraft

    NASA Technical Reports Server (NTRS)

    Proffitt, M. H.; Steinkamp, M. J.; Powell, J. A.; Mclaughlin, R. J.; Mills, O. A.; Schmeltekopf, A. L.; Thompson, T. L.; Tuck, A. F.; Tyler, T.; Chan, K. R.

    1989-01-01

    In situ ozone measurements were made from the ER-2 aircraft during the 1987 Airborne Antarctic Ozone Experiment both inside and outside the ozone hole. Midday measurements from late August until late September during aircraft ascent near 53 deg S latitude indicate no clear temporal trend in ozone mixing ratio but instead reflect the distance of the measurement from the chemically perturbed region. The measurements made within the ozone hole at 72 deg S show altitude-dependent decreases in ozone of 61 percent at a potential temperature of 425 K down to 39 percent at 365 K. Temporal trends are also calculated at various positions relative to the boundary of the chemically perturbed region to locate the region of large ozone decreases and thereby accurately locate the boundary of the ozone hole.

  2. In situ ozone measurements within the 1987 Antarctic ozone hole from a high-altitude ER-2 aircraft

    SciTech Connect

    Proffitt, M.H.; Steinkamp, M.J.; Powell, J.A. Univ. of Colorado, Boulder ); McLaughlin, R.J.; Mills, O.A.; Schmeltekopf, A.L.; Thompson, T.L.; Tuck, A.F.; Tyler, T.; Winkler, R.H. ); Chan, K.R. )

    1989-11-30

    In situ ozone measurements were made from the ER-2 aircraft during the 1987 Airborne Antarctic Ozone Experiment both inside and outside the ozone hole. Midday measurements from late August until late September during aircraft ascent near 53{degree}S latitude indicate no clear temporal trend in ozone mixing ratio but instead reflect the distance of the measurement from the chemically perturbed region. The measurements made within the ozone hole at 72{degree}S show altitude dependent decreases in ozone of 61% at a potential temperature of 425 K down to 39% at 365 K. Temporal trends are also calculated at various positions relative to the boundary of the chemically perturbed region to locate the region of large ozone decreases and thereby accurately locate the boundary of the ozone hole.

  3. Sulfuric acid measurements in the exhaust plume of a jet aircraft in flight: Implications for the sulfuric acid formation efficiency

    NASA Astrophysics Data System (ADS)

    Curtius, J.; Arnold, F.; Schulte, P.

    2002-04-01

    Sulfuric acid concentrations were measured in the exhaust plume of a B737-300 aircraft in flight. The measurements were made onboard of the German research aircraft Falcon using the Volatile Aerosol Component Analyzer (VACA). The VACA measures total H2SO4, which is the sum of gaseous H2SO4 and aerosol H2SO4. Measurements took place at distances of 25-200 m behind the B737 corresponding to plume ages of about 0.1-1 seconds. The fuel sulfur content (FSC) of the fuel burned by the B737 engines was alternatively 2.6 and 56 mg sulfur per kilogram fuel (ppmm). H2SO4 concentrations measured in the plume for the 56 ppmm sulfur case were up to ~600 pptv. The average concentration of H2SO4 measured in the ambient atmosphere outside the aircraft plume was 88 pptv, the maximum ambient atmospheric H2SO4 was ~300 pptv. Average efficiencies ɛΔCO2 = 3.3 +/- 1.8% and ɛΔT = 2.9 +/- 1.6% for fuel sulfur conversion to sulfuric acid were inferred when relating the H2SO4 data to measurements of the plume tracers ΔCO2 and ΔT.

  4. Trajectory-Based Complexity (TBX): A Modified Aircraft Count to Predict Sector Complexity During Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Lee, Paul U.

    2011-01-01

    In this paper we introduce a new complexity metric to predict -in real-time- sector complexity for trajectory-based operations (TBO). TBO will be implemented in the Next Generation Air Transportation System (NextGen). Trajectory-Based Complexity (TBX) is a modified aircraft count that can easily be computed and communicated in a TBO environment based upon predictions of aircraft and weather trajectories. TBX is scaled to aircraft count and represents an alternate and additional means to manage air traffic demand and capacity with more consideration of dynamic factors such as weather, aircraft equipage or predicted separation violations, as well as static factors such as sector size. We have developed and evaluated TBX in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center during human-in-the-loop studies of trajectory-based concepts since 2009. In this paper we will describe the TBX computation in detail and present the underlying algorithm. Next, we will describe the specific TBX used in an experiment at NASA's AOL. We will evaluate the performance of this metric using data collected during a controller-inthe- loop study on trajectory-based operations at different equipage levels. In this study controllers were prompted at regular intervals to rate their current workload on a numeric scale. When comparing this real-time workload rating to the TBX values predicted for these time periods we demonstrate that TBX is a better predictor of workload than aircraft count. Furthermore we demonstrate that TBX is well suited to be used for complexity management in TBO and can easily be adjusted to future operational concepts.

  5. Artificial Intelligence (AI) Based Tactical Guidance for Fighter Aircraft

    NASA Technical Reports Server (NTRS)

    McManus, John W.; Goodrich, Kenneth H.

    1990-01-01

    A research program investigating the use of Artificial Intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range (WVR) air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS), a second generation TDG, is presented. The Knowledge-Based Systems used by CLAWS to aid in the tactical decision-making process are outlined in detail, and the results of tests to evaluate the performance of CLAWS versus a baseline TDG developed in FORTRAN to run in real-time in the Langley Differential Maneuvering Simulator (DMS), are presented. To date, these test results have shown significant performance gains with respect to the TDG baseline in one-versus-one air combat engagements, and the AI-based TDG software has proven to be much easier to modify and maintain than the baseline FORTRAN TDG programs. Alternate computing environments and programming approaches, including the use of parallel algorithms and heterogeneous computer networks are discussed, and the design and performance of a prototype concurrent TDG system are presented.

  6. Interoperability of satellite-based augmentation systems for aircraft navigation

    NASA Astrophysics Data System (ADS)

    Dai, Donghai

    The Federal Aviation Administration (FAA) is pioneering a transformation of the national airspace system from its present ground based navigation and landing systems to a satellite based system using the Global Positioning System (GPS). To meet the critical safety-of-life aviation positioning requirements, a Satellite-Based Augmentation System (SBAS), the Wide Area Augmentation System (WAAS), is being implemented to support navigation for all phases of flight, including Category I precision approach. The system is designed to be used as a primary means of navigation, capable of meeting the Required Navigation Performance (RNP), and therefore must satisfy the accuracy, integrity, continuity and availability requirements. In recent years there has been international acceptance of Global Navigation Satellite Systems (GNSS), spurring widespread growth in the independent development of SBASs. Besides the FAA's WAAS, the European Geostationary Navigation Overlay Service System (EGNOS) and the Japan Civil Aviation Bureau's MTSAT-Satellite Augmentation System (MSAS) are also being actively developed. Although all of these SBASs can operate as stand-alone, regional systems, there is increasing interest in linking these SBASs together to reduce costs while improving service coverage. This research investigated the coverage and availability improvements due to cooperative efforts among regional SBAS networks. The primary goal was to identify the optimal interoperation strategies in terms of performance, complexity and practicality. The core algorithms associated with the most promising concepts were developed and demonstrated. Experimental verification of the most promising concepts was conducted using data collected from a joint international test between the National Satellite Test Bed (NSTB) and the EGNOS System Test Bed (ESTB). This research clearly shows that a simple switch between SBASs made by the airborne equipment is the most effective choice for achieving the

  7. Measurement of OH, H2SO4, MSA, NH3 and DMSO Aboard the NASA P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, Fred

    2001-01-01

    This project involved the installation of a downsized multichannel mass spectrometer instrument on the NASA P-3B aircraft and its subsequent use on the PEM-Tropics B mission. The new instrument performed well, measuring a number of difficult-to-measure compounds and providing much new photochemical and sulfur data as well as possibly uncovering a new nighttime DMSO source. The details of this effort are discussed.

  8. Aircraft Detection in High-Resolution SAR Images Based on a Gradient Textural Saliency Map.

    PubMed

    Tan, Yihua; Li, Qingyun; Li, Yansheng; Tian, Jinwen

    2015-09-11

    This paper proposes a new automatic and adaptive aircraft target detection algorithm in high-resolution synthetic aperture radar (SAR) images of airport. The proposed method is based on gradient textural saliency map under the contextual cues of apron area. Firstly, the candidate regions with the possible existence of airport are detected from the apron area. Secondly, directional local gradient distribution detector is used to obtain a gradient textural saliency map in the favor of the candidate regions. In addition, the final targets will be detected by segmenting the saliency map using CFAR-type algorithm. The real high-resolution airborne SAR image data is used to verify the proposed algorithm. The results demonstrate that this algorithm can detect aircraft targets quickly and accurately, and decrease the false alarm rate.

  9. Aircraft Detection in High-Resolution SAR Images Based on a Gradient Textural Saliency Map

    PubMed Central

    Tan, Yihua; Li, Qingyun; Li, Yansheng; Tian, Jinwen

    2015-01-01

    This paper proposes a new automatic and adaptive aircraft target detection algorithm in high-resolution synthetic aperture radar (SAR) images of airport. The proposed method is based on gradient textural saliency map under the contextual cues of apron area. Firstly, the candidate regions with the possible existence of airport are detected from the apron area. Secondly, directional local gradient distribution detector is used to obtain a gradient textural saliency map in the favor of the candidate regions. In addition, the final targets will be detected by segmenting the saliency map using CFAR-type algorithm. The real high-resolution airborne SAR image data is used to verify the proposed algorithm. The results demonstrate that this algorithm can detect aircraft targets quickly and accurately, and decrease the false alarm rate. PMID:26378543

  10. A survey of autonomous vision-based See and Avoid for Unmanned Aircraft Systems

    NASA Astrophysics Data System (ADS)

    Mcfadyen, Aaron; Mejias, Luis

    2016-01-01

    This paper provides a comprehensive review of the vision-based See and Avoid problem for unmanned aircraft. The unique problem environment and associated constraints are detailed, followed by an in-depth analysis of visual sensing limitations. In light of such detection and estimation constraints, relevant human, aircraft and robot collision avoidance concepts are then compared from a decision and control perspective. Remarks on system evaluation and certification are also included to provide a holistic review approach. The intention of this work is to clarify common misconceptions, realistically bound feasible design expectations and offer new research directions. It is hoped that this paper will help us to unify design efforts across the aerospace and robotics communities.

  11. A.I.-based real-time support for high performance aircraft operations

    NASA Technical Reports Server (NTRS)

    Vidal, J. J.

    1985-01-01

    Artificial intelligence (AI) based software and hardware concepts are applied to the handling system malfunctions during flight tests. A representation of malfunction procedure logic using Boolean normal forms are presented. The representation facilitates the automation of malfunction procedures and provides easy testing for the embedded rules. It also forms a potential basis for a parallel implementation in logic hardware. The extraction of logic control rules, from dynamic simulation and their adaptive revision after partial failure are examined. It uses a simplified 2-dimensional aircraft model with a controller that adaptively extracts control rules for directional thrust that satisfies a navigational goal without exceeding pre-established position and velocity limits. Failure recovery (rule adjusting) is examined after partial actuator failure. While this experiment was performed with primitive aircraft and mission models, it illustrates an important paradigm and provided complexity extrapolations for the proposed extraction of expertise from simulation, as discussed. The use of relaxation and inexact reasoning in expert systems was also investigated.

  12. Aircraft Detection in High-Resolution SAR Images Based on a Gradient Textural Saliency Map.

    PubMed

    Tan, Yihua; Li, Qingyun; Li, Yansheng; Tian, Jinwen

    2015-01-01

    This paper proposes a new automatic and adaptive aircraft target detection algorithm in high-resolution synthetic aperture radar (SAR) images of airport. The proposed method is based on gradient textural saliency map under the contextual cues of apron area. Firstly, the candidate regions with the possible existence of airport are detected from the apron area. Secondly, directional local gradient distribution detector is used to obtain a gradient textural saliency map in the favor of the candidate regions. In addition, the final targets will be detected by segmenting the saliency map using CFAR-type algorithm. The real high-resolution airborne SAR image data is used to verify the proposed algorithm. The results demonstrate that this algorithm can detect aircraft targets quickly and accurately, and decrease the false alarm rate. PMID:26378543

  13. Weibull-Based Design Methodology for Rotating Aircraft Engine Structures

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin; Hendricks, Robert C.; Soditus, Sherry

    2002-01-01

    The NASA Energy Efficient Engine (E(sup 3)-Engine) is used as the basis of a Weibull-based life and reliability analysis. Each component's life and thus the engine's life is defined by high-cycle fatigue (HCF) or low-cycle fatigue (LCF). Knowing the cumulative life distribution of each of the components making up the engine as represented by a Weibull slope is a prerequisite to predicting the life and reliability of the entire engine. As the engine Weibull slope increases, the predicted lives decrease. The predicted engine lives L(sub 5) (95 % probability of survival) of approximately 17,000 and 32,000 hr do correlate with current engine maintenance practices without and with refurbishment. respectively. The individual high pressure turbine (HPT) blade lives necessary to obtain a blade system life L(sub 0.1) (99.9 % probability of survival) of 9000 hr for Weibull slopes of 3, 6 and 9, are 47,391 and 20,652 and 15,658 hr, respectively. For a design life of the HPT disks having probable points of failure equal to or greater than 36,000 hr at a probability of survival of 99.9 %, the predicted disk system life L(sub 0.1) can vary from 9,408 to 24,911 hr.

  14. Immunity-based detection, identification, and evaluation of aircraft sub-system failures

    NASA Astrophysics Data System (ADS)

    Moncayo, Hever Y.

    This thesis describes the design, development, and flight-simulation testing of an integrated Artificial Immune System (AIS) for detection, identification, and evaluation of a wide variety of sensor, actuator, propulsion, and structural failures/damages including the prediction of the achievable states and other limitations on performance and handling qualities. The AIS scheme achieves high detection rate and low number of false alarms for all the failure categories considered. Data collected using a motion-based flight simulator are used to define the self for an extended sub-region of the flight envelope. The NASA IFCS F-15 research aircraft model is used and represents a supersonic fighter which include model following adaptive control laws based on non-linear dynamic inversion and artificial neural network augmentation. The flight simulation tests are designed to analyze and demonstrate the performance of the immunity-based aircraft failure detection, identification and evaluation (FDIE) scheme. A general robustness analysis is also presented by determining the achievable limits for a desired performance in the presence of atmospheric perturbations. For the purpose of this work, the integrated AIS scheme is implemented based on three main components. The first component performs the detection when one of the considered failures is present in the system. The second component consists in the identification of the failure category and the classification according to the failed element. During the third phase a general evaluation of the failure is performed with the estimation of the magnitude/severity of the failure and the prediction of its effect on reducing the flight envelope of the aircraft system. Solutions and alternatives to specific design issues of the AIS scheme, such as data clustering and empty space optimization, data fusion and duplication removal, definition of features, dimensionality reduction, and selection of cluster/detector shape are also

  15. Design and evaluation of an onboard computer-based information system for aircraft

    NASA Technical Reports Server (NTRS)

    Rouse, S. H.; Rouse, W. B.; Hammer, J. M.

    1982-01-01

    Information seeking by human operators of technical systems is considered. Types of information and forms of presentation are discussed and important issues reviewed. This broad discussion provides a framework within which flight management is considered. The design of an onboard computer-based information system for aircraft is discussed. The aiding possibilities of a computer-based system are emphasized. Results of an experimental evaluation of a prototype system are presented. It is concluded that a computer-based information system can substantially lessen the frequency of human errors.

  16. Comparison of methane emissions from wetlands measured from aircraft and towers

    NASA Astrophysics Data System (ADS)

    Conley, S. A.; Faloona, I. C.; Drexler, J. Z.; Anderson, F. E.; Baldocchi, D. D.; Sturtevant, C. S.; Verfaillie, J. G.; Knox, S. H.

    2013-12-01

    The ability to estimate surface fluxes from light, fixed-wing aircraft is investigated during two flights over Twitchell Island, a heavily managed peatland dominated by irrigated crops approximately 6 km x 3 km in the Sacramento Delta. Flux towers provide a continuous measurement at a single point, while airborne fluxes provide a snapshot of a large area at a given time. The ability to integrate the two methods would provide a means to estimate a continuous regional flux from tower measurements. The single engine airplane (Mooney TLS), provided by Scientific Aviation, was flown around the island while concurrent flux measurements (latent & sensible heat, CO2, CH4) were being made from 4 m towers at two locations on the surface. The flux estimate made with the airplane uses horizontal mean wind measured in real-time from the airplane and the methane mixing ratio measured onboard with a Picarro f2301 analyzer. During the flights there was clear periodicity in all scalars measured coincident with the flight time required to circle the island (~6 minutes), indicating a connection between the surface and the observed signal in the airplane. For methane, higher mixing ratios were observed on the downwind side of the island. An internal boundary layer was observed, which we believe resulted from the Montezuma Hills wind farms upwind of Twitchell Island. Scalars were well-mixed throughout the depth of that internal boundary layer (~500m), which is shown to be consistent with a theoretical estimate of the internal boundary layer given the transition from the wind farm to the island vegetation. Surface emissions were estimated using a mass-balance approach where each of the terms in the scalar budget equation are estimated using a least squares minimization of the data while the airplane was within 10 km of the center of the island and the altitude was below 300 meters. Surface emission of methane during the first flight was estimated at 36 × 13 nmol m-2 s-1. During the

  17. Aircraft Measurements of Convective System Vertical Structure and Coldpools during the DYNAMO Project

    NASA Astrophysics Data System (ADS)

    Guy, N.; Jorgensen, D. P.; Chen, S. S.; Wang, Q.

    2012-12-01

    The DYNAMO (Dynamics of the Madden-Julian Oscillation) field experiment employed a large number of measurement platforms with which to study environmental and convective cloud system characteristics of the MJO initiation region in the Indian Ocean. One such platform, the NOAA P-3 instrumented aircraft, provided mobility to sample convective cloud systems along with the surrounding environment. The tail-mounted, X-band Doppler radar allowed a pseudo-dual-Doppler analysis technique to study system kinematics and derive vertical wind motion. GPS dropwindsondes provided a robust means for thermodynamic characterization both in and around the sampled convective cloud systems. This presentation will focus on the relationships between coldpool strength and depth (along with other environmental characteristics) and the vertical structure of convective systems. In addition, a comparison of the DYNAMO observations to previous results in the region (e.g. TOGA COARE) will be presented. Differences in organizational aspects of convective clouds into mesoscale convective systems between the studies will provide a context of regional differences, which may serve as a basis for future model simulations.

  18. Simulation and analysis of dynamic heating in the ultrafast aircraft thermometer measurements

    NASA Astrophysics Data System (ADS)

    Rosa, Bogdan; Bajer, Konrad; Haman, Krzysztof E.; Szoplik, Tomasz

    2005-10-01

    The ultrafast aircraft thermometer is an airborne device designed for measuring temperature in clouds with centimeter spatial resolution. Its sensor consists of 5mm long and 2.5μm thick thermo-resistive wire protected against impact of cloud droplets by a shield in the form of a suitably shaped rod, placed upstream. However the disturbances of airflow around this rod result in noise in the temperature record. Suction applied through slits located on both sides of the rod reduces the noise generated by vortices shed from the rod and lowers the probability of droplet-wire collisions. Our recent theoretical analysis and numerical simulations led to optimization of this device and additionally clarified the role of the sampling method in processing of the analogue output of the thermometer. In this paper we try to deepen our understanding of the nature of the noise as well as to improve calculations of the corrections connected with the dynamic heating. For this purpose we have done extensive three-dimensional numerical simulations of the airflow around the protective rod and the sensing wire, which permitted precise computation of dynamic heating and showed how applying the suction removes the thermal boundary layer from the rod and damps the sources of the noise.

  19. Flux measurements by the NRC Twin Otter atmospheric research aircraft: 1987-2011

    NASA Astrophysics Data System (ADS)

    Desjardins, Raymond L.; Worth, Devon E.; MacPherson, J. Ian; Bastian, Matthew; Srinivasan, Ramesh

    2016-03-01

    Over the past 30 years, the Canadian Twin Otter research group has operated an aircraft platform for the study of atmospheric greenhouse gas fluxes (carbon dioxide, ozone, nitrous oxide and methane) and energy exchange (latent and sensible heat) over a wide range of terrestrial ecosystems in North America. Some of the acquired data from these projects have now been archived at the Flight Research Laboratory and Agriculture and Agri-Food Canada. The dataset, which contains the measurements obtained in eight projects from 1987 to 2011 are now publicly available. All these projects were carried out in order to improve our understanding of the biophysical controls acting on land-surface atmosphere fluxes. Some of the projects also attempted to quantify the impacts of agroecosystems on the environment. To provide information on the data available, we briefly describe each project and some of the key findings by referring to previously published relevant work. As new flux analysis techniques are being developed, we are confident that much additional information can be extracted from this unique data set.

  20. An overview of reactive chlorine measurements during the WINTER C-130 aircraft campaign

    NASA Astrophysics Data System (ADS)

    Thornton, J. A.; Lopez-Hilfiker, F.; Lee, B. H.; Jaegle, L.; Haskins, J.; Shah, V.; Brown, S. S.; Fibiger, D. L.; McDuffie, E. E.; Veres, P. R.; Dibb, J. E.; Sparks, T.; Ebben, C. J.; Cohen, R. C.; Sullivan, A.; Guo, H.; Weber, R. J.; Schroder, J. C.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Campos, T. L.; Weinheimer, A. J.; Apel, E. C.; Blake, N. J.

    2015-12-01

    As part of the Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER) campaign, the University of Washington Iodide-adduct high resolution time of flight chemical ionization mass spectrometer (HRToF-CIMS) was deployed aboard the NSF/NCAR C-130 aircraft. Calibrated measurements of ClNO2, Cl2, HCl, N2O5, HNO3, HONO, among several other compounds, were made at 2Hz on all 13 research flights. ClNO2 and HCl were often the dominant forms of reactive gas-phase chlorine compounds, with ClNO2 routinely reaching >1.5 ppb in the polluted outflow of the eastern U.S. urban corridor. ClNO2 often becomes a substantial fraction (~30%) of NOz (NOz = NOy - NOx) in these plumes at night. Preliminary analyses suggests that ClNO2 production is most efficient in the polluted marine boundary layer, with yields approaching unity and the evolution of nighttime ClNO2 highly correlated with that of HNO3 and particulate nitrate. However, ClNO2 production was observed throughout the region and a significant source of reactive chlorine from coal-fired power plants was directly confirmed with measurements of HCl strongly correlated with SO2. In addition, there is some evidence that biomass or biofuel combustion is a source of reactive chlorine that can lead to ClNO2 production. Examples of the nocturnal and diel evolution of reactive chlorine species are given, and we show to our knowledge the first measurements of chlorine nitrate (ClONO2) in the polluted mid-latitude marine boundary layer.

  1. Piezomechatronic-based systems in aircraft, space, and defense applications

    NASA Astrophysics Data System (ADS)

    Maillard, T.; Claeyssen, F.; LeLetty, R.; Sosnicki, O.; Pages, A.; Vazquez Carazo, A.

    2009-05-01

    mechatronic based system such like, piezo micro-scanning stage for IR camera resolution enhancement, piezo active flap on helicopter blade for noise reduction, micro amplified piezo actuator for tilting MAV rotor, hollow piezo actuator for external laser cavity tuning of a space LIDAR, in order to discuss the state-of-the-art performance and deduce further needs.

  2. HALO aircraft measurements of East Asian anthropogenic SO2 import into the lower stratosphere by a warm conveyor belt uplift

    NASA Astrophysics Data System (ADS)

    Schlager, H.; Arnold, F.; Aufmhoff, H.; Baumann, R.; Pirjola, L.; Roiger, A.; Sailer, T.; Wirth, M.; Schumann, U.

    2012-04-01

    We report on a case study of anthropogenic SO2 pollution transport into the lower stratosphere from East Asian source regions. The pollution layer was observed over Central Europe by measurements from the new German research aircraft HALO. The layer contained enhanced SO2, HNO3 and water vapor and caused increased Lidar backscatter radiation. Meteorological analysis and air mass transport and dispersion model simulations reveal that the detected pollutants were released from ground-based sources in East-China, South-Korea, and Japan. The pollution plume was uplifted by a warm conveyor belt associated with a West-Pacific cyclone and finally injected into the lower stratosphere. Our HALO measurements were performed 5 days after the air mass uplift event, when significant parts of the Northern Hemisphere were already covered by the pollution plume. Accompanying trajectory chemistry and aerosol box model simulations indicate that H2SO4/H2O aerosol droplets were generated in the SO2-rich plume and grew to sizes large enough to explain the observed increased Lidar backscatter signal. Implications of the SO2 transport pathway into the lower stratosphere presented in this study will be discussed.

  3. NASA-UVa Light Aerospace Alloy and Structures Technology Program: Aluminum-Based Materials for High Speed Aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr. (Editor)

    1996-01-01

    This report is concerned with 'Aluminum-Based Materials for High Speed Aircraft' which was initiated to identify the technology needs associated with advanced, low-cost aluminum base materials for use as primary structural materials. Using a reference baseline aircraft, these materials concept will be further developed and evaluated both technically and economically to determine the most attractive combinations of designs, materials, and manufacturing techniques for major structural sections of an HSCT. Once this has been accomplished, the baseline aircraft will be resized, if applicable, and performance objectives and economic evaluations made to determine aircraft operating costs. The two primary objectives of this study are: (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials, and (2) to assess these materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT.

  4. A comparison of ground-based and aircraft-based methane emission flux estimates in a western oil and natural gas production basin

    NASA Astrophysics Data System (ADS)

    Snare, Dustin A.

    Recent increases in oil and gas production from unconventional reservoirs has brought with it an increase of methane emissions. Estimating methane emissions from oil and gas production is complex due to differences in equipment designs, maintenance, and variable product composition. Site access to oil and gas production equipment can be difficult and time consuming, making remote assessment of emissions vital to understanding local point source emissions. This work presents measurements of methane leakage made from a new ground-based mobile laboratory and a research aircraft around oil and gas fields in the Upper Green River Basin (UGRB) of Wyoming in 2014. It was recently shown that the application of the Point Source Gaussian (PSG) method, utilizing atmospheric dispersion tables developed by US EPA (Appendix B), is an effective way to accurately measure methane flux from a ground-based location downwind of a source without the use of a tracer (Brantley et al., 2014). Aircraft measurements of methane enhancement regions downwind of oil and natural gas production and Planetary Boundary Layer observations are utilized to obtain a flux for the entire UGRB. Methane emissions are compared to volumes of natural gas produced to derive a leakage rate from production operations for individual production sites and basin-wide production. Ground-based flux estimates derive a leakage rate of 0.14 - 0.78 % (95 % confidence interval) per site with a mass-weighted average (MWA) of 0.20 % for all sites. Aircraft-based flux estimates derive a MWA leakage rate of 0.54 - 0.91 % for the UGRB.

  5. Constraining the 2012-2014 growing season Alaskan methane budget using CARVE aircraft measurements

    NASA Astrophysics Data System (ADS)

    Hartery, S.; Chang, R. Y. W.; Commane, R.; Lindaas, J.; Miller, S. M.; Wofsy, S. C.; Karion, A.; Sweeney, C.; Miller, C. E.; Dinardo, S. J.; Steiner, N.; McDonald, K. C.; Watts, J. D.; Zona, D.; Oechel, W. C.; Kimball, J. S.; Henderson, J.; Mountain, M. E.

    2015-12-01

    Soil in northen latitudes contains rich carbon stores which have been historically preserved via permafrost within the soil bed; however, recent surface warming in these regions is allowing deeper soil layers to thaw, influencing the net carbon exchange from these areas. Due to the extreme nature of its climate, these eco-regions remain poorly understood by most global models. In this study we analyze methane fluxes from Alaska using in situ aircraft observations from the 2012-2014 Carbon in Arctic Reservoir Vulnerability Experiment (CARVE). These observations are coupled with an atmospheric particle transport model which quantitatively links surface emissions to atmospheric observations to make regional methane emission estimates. The results of this study are two-fold. First, the inter-annual variability of the methane emissions was found to be <1 Tg over the area of interest and is largely influenced by the length of time the deep soil remains unfrozen. Second, the resulting methane flux estimates and mean soil parameters were used to develop an empirical emissions model to help spatially and temporally constrain the methane exchange at the Alaskan soil surface. The empirical emissions model will provide a basis for exploring the sensitivity of methane emissions to subsurface soil temperature, soil moisture, organic carbon content, and other parameters commonly used in process-based models.

  6. Aircraft measurements of the mean and turbulent structure of marine stratocumulus clouds during FIRE

    NASA Technical Reports Server (NTRS)

    Albrecht, Bruce A.; Kloesel, Kevin A.; Moyer, Kerry A.; Nucciarone, Jefferey J.; Young, George

    1990-01-01

    The mean and turbulent structure of marine stratocumulus clouds is defined from data that were collected from 10 flights made with the National Center for Atmospheric Research (NCAR) Electra during the First ISCCP Regional Experiment (FIRE). The number of cases sampled is sufficiently large that researchers can compare the boundary layer structure obtained (1) for solid and broken cloud conditions, (2) for light and strong surface wind conditions, (3) for different sea-surface temperatures, and (4) on day and night flights. Researchers will describe the cloud and synoptic conditions present at the time of the Electra flights and show how those flights were coordinated with the operations of other aircraft and with satellite overpasses. Mean thermodynamic and wind profiles and the heat, moisture, and momentum fluxes obtained from data collected during these flights will be compared. Variations in the cloud-top structure will be quantified using LIDAR data collected during several of the Electra flights. The spatial structure of cloud-top height and the cloud-base height will be compared with the turbulent structure in the boundary layer as defined by spectra and cospectra of the wind, temperature, and moisture.

  7. Unmanned Aircraft in the Measurement of Carbon Dioxide in Buoyant Plumes

    NASA Astrophysics Data System (ADS)

    Jacob, J.

    2015-12-01

    Carbon sequestration, the storage of carbon dioxide gas underground, has the potential to reduce global warming by removing a greenhouse gas from the atmosphere. These storage sites, however, must first be monitored to detect if carbon dioxide is leaking back out to the atmosphere. As an alternative to traditional large ground-based sensor networks to monitor CO2 levels for leaks, unmanned aircraft offer the potential to perform in-situ atmospheric leak detection over large areas for a fraction of the cost. This project developed a proof-of-concept sensor system to map relative carbon dioxide levels to detect potential leaks. Ground tests were performed to verify and calibrate the system including wind tunnel tests to determine the optimal configuration of the system to account for dynamic calibration models required to determine accurate location of gas concentration in (x,y,z,t). Field tests were then conducted over a controlled release of CO2 as well as over controlled rangeland fires which released carbon dioxide over a large area. 3D maps of carbon dioxide were developed from the system telemetry that clearly illustrated increased CO2 levels from the fires. Results are compared with dynamic atmospheric models of gas dispersion within plumes.

  8. Measured Changes in C-Band Radar Reflectivity of Clear Air Caused by Aircraft Wake Vortices

    NASA Technical Reports Server (NTRS)

    Mackenzie, Anne I.

    1997-01-01

    Wake vortices from a C-130 airplane were observed at the NASA Wallops Flight Facility with a ground-based, monostatic C-band radar and an antenna-mounted boresight video camera. The airplane wake was viewed from a distance of approximately 1 km, and radar scanning was adjusted to cross a pair of marker smoke trails generated by the C-130. For each airplane pass, changes in radar reflectivity were calculated by subtracting the signal magnitudes during an initial clutter scan from the signal magnitudes during vortex-plus-clutter scans. The results showed both increases and decreases in reflectivity on and near the smoke trails in a characteristic sinusoidal pattern of heightened reflectivity in the center and lessened reflectivity at the sides. Reflectivity changes in either direction varied from -131 to -102 dBm(exp -1); the vortex-plus-clutter to noise ratio varied from 20 to 41 dB. The radar recordings lasted 2.5 min each; evidence of wake vortices was found for up to 2 min after the passage of the airplane. Ground and aircraft clutter were eliminated as possible sources of the disturbance by noting the occurrence of vortex signatures at different positions relative to the ground and the airplane. This work supports the feasibility of vortex detection by radar, and it is recommended that future radar vortex detection be done with Doppler systems.

  9. Balloon-borne and aircraft infrared measurements of ethane (C2H6) in the upper troposphere and lower stratosphere

    NASA Technical Reports Server (NTRS)

    Goldman, A.; Murcray, F. J.; Murcray, D. G.; Rinsland, C. P.; Coffey, M. T.; Mankin, W. G.

    1984-01-01

    Quantitative infrared measurements of ethane (C2H6) in the upper troposphere and lower stratosphere are reported. The results have been obtained from the analysis of absorption features of the nu9 band at 12.2 microns, which have been identified in high-resolution balloon-borne and aircraft solar absorption spectra. The balloon-borne spectral data were recorded at sunset with the 0.02/cm resolution University of Denver interferometer system, from a float altitude of 33.5 km near Alamogordo, New Mexico, on March 23, 1981. The aircraft spectra were recorded at sunset in July 1978 with a 0.06/cm resolution interferometer aboard a jet aircraft at 12 km altitude, near 35 deg N, 96 deg W. The balloon analysis indicates the C2H6 mixing ratio decreased from 3.5 ppbv near 8.8 km to 0.91 ppbv near 12.1 km. The results are consistent with the column value obtained from the aircraft data.

  10. Balloon-borne and aircraft infrared measurements of ethane (C2H6) in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Goldman, A.; Murcray, F. J.; Murcray, D. G.; Rinsland, C. P.; Coffey, M. T.; Mankin, W. G.

    Quantitative infrared measurements of ethane (C2H6) in the upper troposphere and lower stratosphere are reported. The results have been obtained from the analysis of absorption features of the nu9 band at 12.2 microns, which have been identified in high-resolution balloon-borne and aircraft solar absorption spectra. The balloon-borne spectral data were recorded at sunset with the 0.02/cm resolution University of Denver interferometer system, from a float altitude of 33.5 km near Alamogordo, New Mexico, on March 23, 1981. The aircraft spectra were recorded at sunset in July 1978 with a 0.06/cm resolution interferometer aboard a jet aircraft at 12 km altitude, near 35 deg N, 96 deg W. The balloon analysis indicates the C2H6 mixing ratio decreased from 3.5 ppbv near 8.8 km to 0.91 ppbv near 12.1 km. The results are consistent with the column value obtained from the aircraft data.

  11. Developing an Accurate CFD Based Gust Model for the Truss Braced Wing Aircraft

    NASA Technical Reports Server (NTRS)

    Bartels, Robert E.

    2013-01-01

    The increased flexibility of long endurance aircraft having high aspect ratio wings necessitates attention to gust response and perhaps the incorporation of gust load alleviation. The design of civil transport aircraft with a strut or truss-braced high aspect ratio wing furthermore requires gust response analysis in the transonic cruise range. This requirement motivates the use of high fidelity nonlinear computational fluid dynamics (CFD) for gust response analysis. This paper presents the development of a CFD based gust model for the truss braced wing aircraft. A sharp-edged gust provides the gust system identification. The result of the system identification is several thousand time steps of instantaneous pressure coefficients over the entire vehicle. This data is filtered and downsampled to provide the snapshot data set from which a reduced order model is developed. A stochastic singular value decomposition algorithm is used to obtain a proper orthogonal decomposition (POD). The POD model is combined with a convolution integral to predict the time varying pressure coefficient distribution due to a novel gust profile. Finally the unsteady surface pressure response of the truss braced wing vehicle to a one-minus-cosine gust, simulated using the reduced order model, is compared with the full CFD.

  12. Predictions of F-111 TACT aircraft buffet response and correlations of fluctuating pressures measured on aluminum and steel models and the aircraft

    NASA Technical Reports Server (NTRS)

    Coe, Charles F.; Cunningham, Atlee M., Jr.

    1987-01-01

    Results of buffet research that was conducted as part of the joint USAF/NASA F-111 TACT Research Program are presented. The correlation of wind tunnel and flight measurements of buffet excitation showed that there generally was good agreement between measurements of pressure fluctuations on the models and aircraft in regions of separated flow. At shock-wave boundaries of the separated flow, correlations of pressure fluctuations were not so good, due to Reynolds number and static elastic effects. The buffet prediction method, which applies a forcing function that is obtained by real-time integration of pressure time histories with the natural modes, is described. The generalized forces, including the effects of wing and tail, correlations of predicted and measured damping, and correlations of predicted and measured buffet response are presented. All presented data are for a Mach number of 0.8 with wing-sweep angles of 26 and 35 deg for a range of angles-of-attack that include buffet onset to high intensity buffeting. Generally, the buffet predictions were considered to be quite good particularly in light of past buffet-prediction experience.

  13. Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants.

    PubMed

    Solbu, Kasper; Daae, Hanne Line; Olsen, Raymond; Thorud, Syvert; Ellingsen, Dag Gunnar; Lindgren, Torsten; Bakke, Berit; Lundanes, Elsa; Molander, Paal

    2011-05-01

    Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max

  14. Physical Processes Governing Atmospheric Trace Constituents Measured from an Aircraft on PEM-Tropics

    NASA Technical Reports Server (NTRS)

    Newell, Reginald E.; Hoell, James M., Jr. (Technical Monitor)

    2001-01-01

    Before the mission, the PI (principal investigator) was instrumental in securing real-time use of the new 51-level ECMWF (European Centre for Medium Range Weather Forecasts) meteorological data. During the mission, he provided flight planning and execution guidance as meteorologist for the P-3B. Mr. Yong Zhu computed and plotted meteorological forecast maps using the ECMWF data and transmitted them to the field from MIT (Massachusetts Institute of Technology). Dr. John Cho was in the field for the Christmas Island portion to extract data from the on-site NOAA (National Oceanic and Atmospheric Administration) radars for local wind profiles that were used at the flight planning meetings. When the power supply for the VHF radar failed, he assisted the NOAA engineer in its repair. After the mission, Mr. Zhu produced meteorological data memos, which were made available to the PEM (Pacific Exploratory Mission)-Tropics B science team on request. An undergraduate student, Ms. Danielle Morse, wrote memos annotating the cloud conditions seen on the aircraft external monitor video tapes. Dr. Cho and the PI circulated a memo regarding the status (and associated problems) of the meteorological measurement systems on the DC-8 and P-3B to the relevant people on the science team. Several papers by members of our project were completed and accepted by JGR (Journal of Geophysical Research) for the first special section on PEM-Tropics B. These papers included coverage of the following topics: 1) examination of boundary layer data; 2) water vapor transport; 3) tropospheric trace constituent layers; 4) summarizations of the meteorological background and events during PEM-Tropics B; 5) concomitant lidar measurements of ozone, water vapor, and aerosol.

  15. Aircraft measurements of gases pollutants and particles during CAREBeijing-2008: distributions, characteristics and influencing factors

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Zhu, T.; Yang, W.; Bai, Z.; Sun, Y. L.; Xu, Y.; Yin, B.

    2013-01-01

    Measurements of gaseous pollutants, including ozone (O3), sulfur dioxide (SO2), nitrogen oxides (NOx = NO + NO2), carbon monoxide (CO), particle number concentrations (5.6-560 nm and 0.47-30 μm), and meteorological parameters (T, RH, P) were conducted during the Program of Campaigns of Air Quality Research in Beijing and Surrounding Region (CAREBeijing) from 27 August through 13 October 2008. The data of total 18 flights (70 h flight time) from the ground to 2100 m were obtained by a Yun-12 aircraft in the southern surrounded areas of Beijing (38° N-40° N, 114° E-118° E). This measurement was to characterize the regional variation of air pollution during and after the Olympics of 2008, the impacts of different transport direction and possible influencing factors. Results suggested that four different groups of transport sources influenced the pollution level of pollutants with the consideration of the backward trajectory analysis, including: (1) the pollutant transport of the southern direction with higher pollutants level; (2) the cleaner long-range transport of the northern or northwestern direction with lower pollutants level; (3) the transport from the eastern direction with characteristics of sea sources, i.e. middle level of gases pollutants and higher particle concentration; (4) the transport of mixing directions, i.e. lower altitudes from the pollutant transport direction or local pollution but higher altitudes from the clean transport direction. Additionally, the relatively long-lived CO was shown to be a possible transport tracer of long-range transport of northwestern direction especially on the higher altitudes. Three factors influenced the size distribution of particles, i.e. air mass transport direction, ground source emissions and meteorological influences were also discussed.

  16. Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants.

    PubMed

    Solbu, Kasper; Daae, Hanne Line; Olsen, Raymond; Thorud, Syvert; Ellingsen, Dag Gunnar; Lindgren, Torsten; Bakke, Berit; Lundanes, Elsa; Molander, Paal

    2011-05-01

    Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max

  17. A computer program to obtain time-correlated gust loads for nonlinear aircraft using the matched-filter-based method

    NASA Technical Reports Server (NTRS)

    Scott, Robert C.; Pototzky, Anthony S.; Perry, Boyd, III

    1994-01-01

    NASA Langley Research Center has, for several years, conducted research in the area of time-correlated gust loads for linear and nonlinear aircraft. The results of this work led NASA to recommend that the Matched-Filter-Based One-Dimensional Search Method be used for gust load analyses of nonlinear aircraft. This manual describes this method, describes a FORTRAN code which performs this method, and presents example calculations for a sample nonlinear aircraft model. The name of the code is MFD1DS (Matched-Filter-Based One-Dimensional Search). The program source code, the example aircraft equations of motion, a sample input file, and a sample program output are all listed in the appendices.

  18. Measurement of dose equivalent distribution on-board commercial jet aircraft.

    PubMed

    Kubančák, J; Ambrožová, I; Ploc, O; Pachnerová Brabcová, K; Štěpán, V; Uchihori, Y

    2014-12-01

    The annual effective doses of aircrew members often exceed the limit of 1 mSv for the public due to the increased level of cosmic radiation at the flight altitudes, and thus, it is recommended to monitor them [International Commission on Radiation Protection. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21: (1-3), (1991)]. According to the Monte Carlo simulations [Battistoni, G., Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the doses to aircrew members taking into consideration the aircraft structures. Adv. Space Res. 36: , 1645-1652 (2005) and Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the influence of aircraft shielding on the aircrew exposure through an aircraft mathematical model. Radiat. Prot. Dosim. 108: (2), 91-105 (2004)], the ambient dose equivalent rate Ḣ*(10) depends on the location in the aircraft. The aim of this article is to experimentally evaluate Ḣ*(10) on-board selected types of aircraft. The authors found that Ḣ*(10) values are higher in the front and the back of the cabin and lesser in the middle of the cabin. Moreover, total dosimetry characteristics obtained in this way are in a reasonable agreement with other data, in particular with the above-mentioned simulations. PMID:24344348

  19. Measurement of dose equivalent distribution on-board commercial jet aircraft.

    PubMed

    Kubančák, J; Ambrožová, I; Ploc, O; Pachnerová Brabcová, K; Štěpán, V; Uchihori, Y

    2014-12-01

    The annual effective doses of aircrew members often exceed the limit of 1 mSv for the public due to the increased level of cosmic radiation at the flight altitudes, and thus, it is recommended to monitor them [International Commission on Radiation Protection. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21: (1-3), (1991)]. According to the Monte Carlo simulations [Battistoni, G., Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the doses to aircrew members taking into consideration the aircraft structures. Adv. Space Res. 36: , 1645-1652 (2005) and Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the influence of aircraft shielding on the aircrew exposure through an aircraft mathematical model. Radiat. Prot. Dosim. 108: (2), 91-105 (2004)], the ambient dose equivalent rate Ḣ*(10) depends on the location in the aircraft. The aim of this article is to experimentally evaluate Ḣ*(10) on-board selected types of aircraft. The authors found that Ḣ*(10) values are higher in the front and the back of the cabin and lesser in the middle of the cabin. Moreover, total dosimetry characteristics obtained in this way are in a reasonable agreement with other data, in particular with the above-mentioned simulations.

  20. Aircraft measurements of the impacts of urban plume on cloud activation properties during GoAmazon - preliminary results

    NASA Astrophysics Data System (ADS)

    Mei, F.; Comstock, J. M.; Wang, J.; Tomlinson, J. M.; Hubbe, J. M.; Schmid, B.; Martin, S. T.; Longo, K.; Kuang, C.; Chand, D.; Pekour, M. S.; Shilling, J. E.

    2014-12-01

    Currently, the indirect effects of atmospheric aerosols remain the most uncertain components in forcing of climate change over the industrial period (IPCC, 2007). This large uncertainty is partially a result of our incomplete understanding of the ability of particles to form cloud droplets under atmospherically relevant supersaturations. One of the objectives of the US Department of Energy (DOE) Green Ocean Amazon Project (GoAmazon) is to understand the influence of the emission from Manaus, a tropical megacity, on aerosol size, concentration, and chemical composition, and their impact on aerosol cloud condensation nuclei (CCN) spectrum. During the GoAmazon study, size distributions, CCN spectra and chemical composition of aerosols both under pristine conditions and inside Manaus plume were measured in-situ from the DOE Gulfstream 1 (G-1) research aircraft during two Intensive Operations Periods, one conducted in the wet season (Feb 22- March 24, 2014) and the other in dry season (Sep 1 - Oct 10, 2014). Aerosol size distributions were measured by a Fast Integrated Mobility Spectrometer (FIMS) and compared with the merged size distribution from two other instruments, an Ultra High Sensitivity Aerosol Spectrometer - Airborne (UHSAS-A, DMT), and a Passive Cavity Aerosol Spectrometer Probe (PCASP-200, DMT). Optical measurements of light scattering by nephelometer and absorption by a particle soot absorption photometer (PSAP) were combined with number/size distributions data in a iterative method, which retrieves the effective imaginary refractive index of the particles at a wavelength of 545 nm. Aerosol chemical composition was characterized using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, Aerodyne Inc.). CCN number concentration was measured by a DMT dual column CCN counter at two supersaturations 0.25% and 0.5%. Based on the aerosol properties mentioned above, CCN closure is carried out. In addition, the sensitivity of calculated CCN

  1. Aircraft landing gear systems

    NASA Technical Reports Server (NTRS)

    Tanner, John A. (Editor)

    1990-01-01

    Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

  2. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-03-01

    A detailed understanding of the climate and air quality impacts of aviation requires detailed measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground, 143 m downwind of the engines and characterized as a function of engine power from ground idle (~4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine-idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas phase emissions at idle, and an increasing fraction of the total gas phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (≤30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  3. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-08-01

    A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground 143 m downwind of the engines and characterized as a function of engine power from idle (4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas-phase emissions at idle, and an increasing fraction of the total gas-phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (≤30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  4. Aircraft accident report: NASA 712, Convair 990, N712NA, March Air Force Base, California, July 17, 1985, executive summary

    NASA Technical Reports Server (NTRS)

    Batthauer, Byron E.; Mccarthy, G. T.; Hannah, Michael; Hogan, Robert J.; Marlow, Frank J.; Reynard, William D.; Stoklosa, Janis H.; Yager, Thomas J.

    1986-01-01

    On July 17, l985, NASA 712, a Convair 990 aircraft, was destroyed by fire during an aborted takeoff at March Air Force Base in California. Material ejected from a blowout in the tires of the right main landing gear penetrated the right-wing fuel tank. The leaking fuel ignited. Fire engulfed the right wing and fuselage as the aircraft stopped its forward motion. The crew of four and the 15 scientists and technicians aboard escaped without serious injury.

  5. Measurement and analysis of aircraft engine PM emissions downwind of an active runway at the Oakland International Airport

    NASA Astrophysics Data System (ADS)

    Lobo, Prem; Hagen, Donald E.; Whitefield, Philip D.

    2012-12-01

    The growth of commercial aviation has fueled concerns over air quality around airports and the surrounding communities. Airports must expand their operations to meet the increase in air traffic, but expansion plans have been delayed or canceled due to concerns over local air quality. This paper presents the methodology for real-time measurements of aircraft engine specific Particulate Matter (PM) emissions and analysis of the associated high resolution data acquired during normal Landing and Take-Off (LTO) operations 100-300 m downwind of an active taxi-/runway at the Oakland International Airport. The airframe-engine combinations studied included B737-300 with CFM56-3B engines, B737-700/800 with CFM56-7B engines, A320 with V2500-A5 engines, MD-80 with JT-8D engines, A300 with CF6-80 engines, DC-10 with CF6-50 engines, and CRJ-100/200 with CF34-3B engines. For all engine types studied, the size distributions were typically bimodal in nature with a nucleation mode comprised of freshly nucleated PM and an accumulation mode comprised mostly of PM soot with some condensed volatile material. The PM number-based emission index observed ranged between 7 × 1015-3 × 1017 particles kg-1 fuel burned at idle/taxi and between 4 × 1015-2 × 1017 particles kg-1 fuel burned at take-off, and the associated PM mass-based emission index (EIm) ranged between 0.1 and 0.7 g kg-1 fuel burned at both the idle/taxi and take-off conditions. Older technology engines such as the CFM56-3B and JT8D engines were observed to have as much as 3× higher PM EIm values at take-off compared to newer engine technology such as the CFM56-7B engine. The results from this study provide information for better characterizing evolving PM emissions from in-service commercial aircraft under normal LTO operations and assessing their impact on local and regional air quality and health related impacts.

  6. Aircraft Configuration and Flight Crew Compliance with Procedures While Conducting Flight Deck Based Interval Management (FIM) Operations

    NASA Technical Reports Server (NTRS)

    Shay, Rick; Swieringa, Kurt A.; Baxley, Brian T.

    2012-01-01

    Flight deck based Interval Management (FIM) applications using ADS-B are being developed to improve both the safety and capacity of the National Airspace System (NAS). FIM is expected to improve the safety and efficiency of the NAS by giving pilots the technology and procedures to precisely achieve an interval behind the preceding aircraft by a specific point. Concurrently but independently, Optimized Profile Descents (OPD) are being developed to help reduce fuel consumption and noise, however, the range of speeds available when flying an OPD results in a decrease in the delivery precision of aircraft to the runway. This requires the addition of a spacing buffer between aircraft, reducing system throughput. FIM addresses this problem by providing pilots with speed guidance to achieve a precise interval behind another aircraft, even while flying optimized descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) human-in-the-loop experiment employed 24 commercial pilots to explore the use of FIM equipment to conduct spacing operations behind two aircraft arriving to parallel runways, while flying an OPD during high-density operations. This paper describes the impact of variations in pilot operations; in particular configuring the aircraft, their compliance with FIM operating procedures, and their response to changes of the FIM speed. An example of the displayed FIM speeds used incorrectly by a pilot is also discussed. Finally, this paper examines the relationship between achieving airline operational goals for individual aircraft and the need for ATC to deliver aircraft to the runway with greater precision. The results show that aircraft can fly an OPD and conduct FIM operations to dependent parallel runways, enabling operational goals to be achieved efficiently while maintaining system throughput.

  7. Lyapunov-based control of limit cycle oscillations in uncertain aircraft systems

    NASA Astrophysics Data System (ADS)

    Bialy, Brendan

    Store-induced limit cycle oscillations (LCO) affect several fighter aircraft and is expected to remain an issue for next generation fighters. LCO arises from the interaction of aerodynamic and structural forces, however the primary contributor to the phenomenon is still unclear. The practical concerns regarding this phenomenon include whether or not ordnance can be safely released and the ability of the aircrew to perform mission-related tasks while in an LCO condition. The focus of this dissertation is the development of control strategies to suppress LCO in aircraft systems. The first contribution of this work (Chapter 2) is the development of a controller consisting of a continuous Robust Integral of the Sign of the Error (RISE) feedback term with a neural network (NN) feedforward term to suppress LCO behavior in an uncertain airfoil system. The second contribution of this work (Chapter 3) is the extension of the development in Chapter 2 to include actuator saturation. Suppression of LCO behavior is achieved through the implementation of an auxiliary error system that features hyperbolic functions and a saturated RISE feedback control structure. Due to the lack of clarity regarding the driving mechanism behind LCO, common practice in literature and in Chapters 2 and 3 is to replicate the symptoms of LCO by including nonlinearities in the wing structure, typically a nonlinear torsional stiffness. To improve the accuracy of the system model a partial differential equation (PDE) model of a flexible wing is derived (see Appendix F) using Hamilton's principle. Chapters 4 and 5 are focused on developing boundary control strategies for regulating the bending and twisting deformations of the derived model. The contribution of Chapter 4 is the construction of a backstepping-based boundary control strategy for a linear PDE model of an aircraft wing. The backstepping-based strategy transforms the original system to a exponentially stable system. A Lyapunov-based stability

  8. Tracking and Characterization of Aircraft Wakes Using Acoustic and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Booth, Earl R., Jr.; Humphreys, William M., Jr.

    2005-01-01

    Data from the 2003 Denver International Airport Wake Acoustics Test are further examined to discern spectral content of aircraft wake signatures, and to compare three dimensional wake tracking from acoustic data to wake tracking data obtained through use of continuous wave and pulsed lidar. Wake tracking data derived from acoustic array data agree well with both continuous wave and pulsed lidar in the horizontal plane, but less well with pulsed lidar in the vertical direction. Results from this study show that the spectral distribution of acoustic energy in a wake signature varies greatly with aircraft type.

  9. Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2010-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie

  10. Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    2001-01-01

    The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

  11. A new Methane and carbon dioxide eddy-covariance flux monitor for land-based, sea-based, and aircraft-based applications.

    NASA Astrophysics Data System (ADS)

    Crosson, Eric; Karion, Anna; Law, Beverly; Sweeney, Colm; Christoph, Thomas; Rahn, Thomas; Mc Gillis, Wade

    2010-05-01

    It is now recognized that a comprehensive understanding of global warming's full impact on local and global weather patterns still requires much more data, namely, mapping the atmospheric mixing ratios (concentrations) of carbon dioxide (CO2), methane (CH4). Moreover, even as this understanding becomes more complete, there will also be a major ongoing need to continuously map quantitative levels of these gases to monitor the effects of regional, national and international green house gas (GHG) reduction efforts, as well as to certify compliance. To carry out this effort will require analyzers that can produce continuous, parts-per-billion precision, high accuracy measurements of ambient levels of atmospheric gases at very high data rates over years of operation in land-based, sea-based, as well as aircraft-based applications. A challenge worth considering is to create a single analyzer that can address the GHG measurement needs of virtually all these applications. Such an analyzer would be required to produce slow time-response (e.g. minute to minute data is considered very fast time response), and very high accuracy (which can also be described as precision across a network of independent measurements) as required for atmospheric inversions and some mobile applications as well as fast time-response (e.g. 1 Hz to 10 Hz) and excellent relative precision (without the need for long-term accuracy, or comparability of mixing ratios across multiple sites) as needed for eddy covariance flux measurements. Such an analyzer would give the research community much more flexibility, a wider choice of research applications, reduce overall capital equipment cost, and improve the inter-comparability of GHG measurements across applications. Picarro, Inc. has developed a high speed Cavity Ring-Down Spectroscopy (CRDS) based analyzer, able to measure carbon dioxide (CO2) concentration to a precision (one standard deviation) of 200 parts-per-billion (ppbv), and methane (CH4

  12. Sea Surface Slope Statistics for Intermediate and Shore Scale Ocean Waves Measured Using a Low-Altitude Aircraft

    NASA Technical Reports Server (NTRS)

    Vandemack, Douglas; Crawford, Tim; Dobosy, Ron; Elfouhaily, Tanos; Busalacchi, Antonio J. (Technical Monitor)

    1999-01-01

    Ocean surface remote sensing techniques often rely on scattering or emission linked to shorter- scale gravity-capillary ocean wavelets. However, it is increasingly apparent that slightly longer wavelengths of O(10 to 500 cm) are vital components in the robust sea surface description needed to link varied global remote sensing data sets. This paper describes a sensor suite developed to examine sea surface slope variations in the field using an aircraft flying at very low altitude (below 30 m) and will also provide preliminary measurements detailing changes in slope characteristics versus sea state and friction velocity. Two-dimensional surface slope is measured using simultaneous range measurements from three compact short-range laser altimeters mounted in an equilateral triangle arrangement with spacing of about 1 m. In addition, all three lasers provide independent wave elevation profiles after GPS-aided correction for aircraft altitude. Laser range precision is 1 cm rms while vertical motion correction is 15 cm rms. The measurements are made along-track at approximately 1 m intervals setting the spatial scale of the measurement to cover waves of intermediate to long scale. Products available for this array then include surface elevation, two-dimensional slope distribution, and the cross- and along-track 1-D slope distributions. To complement the laser, a down-looking mm-wave radar scatterometer is centered within the laser array to measure radar backscatter simultaneously with the laser slope. The radar's footprint is nominally 1 m in diameter. Near-vertical radar backscatter is inversely proportional to the small-scale surface slope variance and to the tilt of the underlying (laser-measured) surface facet. Together the laser and radar data provide information on wave roughness from the longest scales down to about 1 cm. These measurements are complemented by aircraft turbulence probe data that provides robust surface flux information.

  13. Moving base simulation evaluation of translational rate command systems for STOVL aircraft in hover

    NASA Technical Reports Server (NTRS)

    Franklin, James A.; Stortz, Michael W.

    1996-01-01

    Using a generalized simulation model, a moving-base simulation of a lift-fan short takeoff/vertical landing fighter aircraft has been conducted on the Vertical Motion Simulator at Ames Research Center. Objectives of the experiment were to determine the influence of system bandwidth and phase delay on flying qualities for translational rate command and vertical velocity command systems. Assessments were made for precision hover control and for landings aboard an LPH type amphibious assault ship in the presence of winds and rough seas. Results obtained define the boundaries between satisfactory and adequate flying qualities for these design features for longitudinal and lateral translational rate command and for vertical velocity command.

  14. A Simulation Based Approach for Contingency Planning for Aircraft Turnaround Operation System Activities in Airline Hubs

    NASA Technical Reports Server (NTRS)

    Adeleye, Sanya; Chung, Christopher

    2006-01-01

    Commercial aircraft undergo a significant number of maintenance and logistical activities during the turnaround operation at the departure gate. By analyzing the sequencing of these activities, more effective turnaround contingency plans may be developed for logistical and maintenance disruptions. Turnaround contingency plans are particularly important as any kind of delay in a hub based system may cascade into further delays with subsequent connections. The contingency sequencing of the maintenance and logistical turnaround activities were analyzed using a combined network and computer simulation modeling approach. Experimental analysis of both current and alternative policies provides a framework to aid in more effective tactical decision making.

  15. Development of hybrid particle tracking algorithms and their applications in airflow measurement within an aircraft cabin mock-up

    NASA Astrophysics Data System (ADS)

    Yan, Wei

    Obtaining reliable experimental airflow data within an indoor environment is a challenging task and critical in studying and solving indoor air quality problems. The Hybrid Particle Tracking Velocimetry (HPTV) system is aimed at fulfilling this need. It was developed based on existing Particle Tracking Velocimety (PTV) and Volumetric Particle Tracking Velocimetry (VPTV) techniques. The HPTV system requires three charge-coupled device (CCD) cameras to view the illuminated flow field and capture the trajectories of the seeded particles. By adopting the hybrid spatial matching and object tracking algorithms, this system can acquire the 3-Dimensional velocity components within a large volume with relatively high spatial and temporal resolution. Synthetic images were employed to validate the performance of three components of the system: image processing, camera calibration and 3D velocity reconstruction. These three components are also the main error sources. The accuracy of the whole algorithm was analyzed and discussed through a back projection approach. The results showed that the algorithms performed effectively and accurately. The reconstructed 3D trajectories and streaks agreed well with the simulated streamline of the particles. As an overall testing and application of the system, HPTV was applied to measure the airflow pattern within a full-scale, five-row section of a Boeing 767-300 aircraft cabin mockup. A complete experimental procedure was developed and strictly followed throughout the experiment. Both global flow field at the whole cabin scale and the local flow field at the breathing zone of one passenger were studied. Each test case was also simulated numerically using a commercial computational fluid dynamic (CFD) package. Through comparison between the results from the numerical simulation and the experimental measurement, the potential model validation capability of the system was demonstrated. Possible reasons explaining the difference between

  16. Airborne aldehydes in cabin-air of commercial aircraft: Measurement by HPLC with UV absorbance detection of 2,4-dinitrophenylhydrazones.

    PubMed

    Rosenberger, Wolfgang; Beckmann, Bibiana; Wrbitzky, Renate

    2016-04-15

    This paper presents the strategy and results of in-flight measurements of airborne aldehydes during normal operation and reported "smell events" on commercial aircraft. The aldehyde-measurement is a part of a large-scale study on cabin-air quality. The aims of this study were to describe cabin-air quality in general and to detect chemical abnormalities during the so-called "smell-events". Adsorption and derivatization of airborne aldehydes on 2,4-dinitrophenylhydrazine coated silica gel (DNPH-cartridge) was applied using tailor-made sampling kits. Samples were collected with battery supplied personal air sampling pumps during different flight phases. Furthermore, the influence of ozone was investigated by simultaneous sampling with and without ozone absorption unit (ozone converter) assembled to the DNPH-cartridges and found to be negligible. The method was validated for 14 aldehydes and found to be precise (RSD, 5.5-10.6%) and accurate (recovery, 98-103 %), with LOD levels being 0.3-0.6 μg/m(3). According to occupational exposure limits (OEL) or indoor air guidelines no unusual or noticeable aldehyde pollution was observed. In total, 353 aldehyde samples were taken from two types of aircraft. Formaldehyde (overall average 5.7 μg/m(3), overall median 4.9 μg/m(3), range 0.4-44 μg/m(3)), acetaldehyde (overall average 6.5 μg/m(3), overall median 4.6, range 0.3-90 μg/m(3)) and mostly very low concentrations of other aldehydes were measured on 108 flights. Simultaneous adsorption and derivatization of airborne aldehydes on DNPH-cartridges to the Schiff bases and their HPLC analysis with UV absorbance detection is a useful method to measure aldehydes in cabin-air of commercial aircraft.

  17. Airborne aldehydes in cabin-air of commercial aircraft: Measurement by HPLC with UV absorbance detection of 2,4-dinitrophenylhydrazones.

    PubMed

    Rosenberger, Wolfgang; Beckmann, Bibiana; Wrbitzky, Renate

    2016-04-15

    This paper presents the strategy and results of in-flight measurements of airborne aldehydes during normal operation and reported "smell events" on commercial aircraft. The aldehyde-measurement is a part of a large-scale study on cabin-air quality. The aims of this study were to describe cabin-air quality in general and to detect chemical abnormalities during the so-called "smell-events". Adsorption and derivatization of airborne aldehydes on 2,4-dinitrophenylhydrazine coated silica gel (DNPH-cartridge) was applied using tailor-made sampling kits. Samples were collected with battery supplied personal air sampling pumps during different flight phases. Furthermore, the influence of ozone was investigated by simultaneous sampling with and without ozone absorption unit (ozone converter) assembled to the DNPH-cartridges and found to be negligible. The method was validated for 14 aldehydes and found to be precise (RSD, 5.5-10.6%) and accurate (recovery, 98-103 %), with LOD levels being 0.3-0.6 μg/m(3). According to occupational exposure limits (OEL) or indoor air guidelines no unusual or noticeable aldehyde pollution was observed. In total, 353 aldehyde samples were taken from two types of aircraft. Formaldehyde (overall average 5.7 μg/m(3), overall median 4.9 μg/m(3), range 0.4-44 μg/m(3)), acetaldehyde (overall average 6.5 μg/m(3), overall median 4.6, range 0.3-90 μg/m(3)) and mostly very low concentrations of other aldehydes were measured on 108 flights. Simultaneous adsorption and derivatization of airborne aldehydes on DNPH-cartridges to the Schiff bases and their HPLC analysis with UV absorbance detection is a useful method to measure aldehydes in cabin-air of commercial aircraft. PMID:26376451

  18. En route noise of two turboprop aircraft

    NASA Technical Reports Server (NTRS)

    Dobrzynski, Werner

    1990-01-01

    In order to weigh en route noise emissions originating from future propfan powered aircraft, a data base of emission levels from conventional turboprop aircraft is needed. For this reason flyover noise measurements on two twin-engine turboprop aircraft were conducted at flight heights between 17,000 and 21,000 ft. Acoustic data are presented together with propeller operational parameters and environmental meteorological data. Narrowband spectral analyses demonstrate the characteristic features of the measured propeller noise signatures: Noise spectra are dominated by the propeller rotational noise fundamental frequency and pronounced noise beats occur as a consequence of different rotational speeds of the propellers.

  19. Total ozone derived from UV spectrophotometer measurements on the NASA CV-990 aircraft for the fall 1976 latitude survey flights

    NASA Technical Reports Server (NTRS)

    Hanser, F. A.

    1977-01-01

    An ultraviolet interference filter spectrophotometer was modified to use a photodiode and was flown on latitude survey flights in the fall of 1976. Comparison with Dobson station total ozone values shows agreement between UVS and Dobson total ozone of + or - 2 percent. The procedure used to convert UVS measured ozone above the aircraft altitude to total ozone above ground level introduces an additional 2 percent deviation for very high altitude UVS ozone data. Under stable aircraft operating conditions, the UVS derived ozone values have a variability, or reproducibility, of better than + or -1 percent. The UVS data from the latitude survey flights yield a detailed latitude profile of total ozone over the Pacific Ocean during November 1976. Significant latitudinal structure in total ozone is found at the middle latitudes (30 deg to 40 deg N and S).

  20. Evaluating source area contributions from aircraft flux measurements over heterogeneous land cover by large eddy simulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The estimation of spatial patterns in surface fluxes from aircraft observations poses several challenges in presence of heterogeneous land cover. In particular, the effects of turbulence on scalar transport and the different behavior of passive (e.g. moisture) versus active (e.g. temperature) scalar...

  1. Application of a cost/performance measurement system on a research aircraft project

    NASA Technical Reports Server (NTRS)

    Diehl, J. J.

    1978-01-01

    The fundamentals of the cost/performance management system used in the procurement of two tilt rotor aircraft for a joint NASA/Army research project are discussed. The contractor's reporting system and the GPO's analyses are examined. The use of this type of reporting system is assessed. Recommendations concerning the use of like systems on future projects are included.

  2. Measures to increase airfield capacity by changing aircraft runway occupancy characteristics

    NASA Technical Reports Server (NTRS)

    Gosling, G. D.; Kanafani, A.; Rockaday, S. L. M.

    1981-01-01

    Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations.

  3. DIAL with heterodyne detection including speckle noise: Aircraft/shuttle measurements of O3, H2O, and NH3 with pulsed tunable CO2 lasers

    NASA Technical Reports Server (NTRS)

    Brockman, P.; Hess, R. V.; Staton, L. D.; Bair, C. H.

    1980-01-01

    Atmospheric trace constituent measurements with higher vertical resolution than attainable with passive radiometers are discussed. Infrared differential absorption lidar (DIAL), which depends on Mie scattering from aerosols, has special advantages for tropospheric and lower stratospheric applications and has great potential importance for measurements from shuttle and aircraft. Differential absorption lidar data reduction involves comparing large amplitude signals which have small differences. The accuracy of the trace constituent concentration inferred from DIAL measurements depends strongly on the errors in determining the amplitude of the signals. Thus, the commonly used SNR expression (signal divided by noise in the absence of signal) is not adequate to describe DIAL measurement accuracy and must be replaced by an expression which includes the random coherent (speckle) noise within the signal. A comprehensive DIAL computer algorithm is modified to include heterodyne detection and speckle noise. Examples for monitoring vertical distributions of O3, H2O, and NH3 using a ground-, aircraft-, or shuttle-based pulsed tunable CO2 laser DIAL system are given.

  4. DIAL with heterodyne detection including speckle noise: Aircraft/shuttle measurements of O3, H2O, and NH3 with pulsed tunable CO2lasers

    NASA Technical Reports Server (NTRS)

    Brockman, P.; Hess, R. V.; Staton, L. D.; Bair, C. H.

    1980-01-01

    A parametric analysis of DIAL sensitivity with heterodyne detection is presented and comparisons with direct detection are discussed. Examples are given for monitoring vertical distributions of O3, H2O, and NH3 using a ground-, aircraft-, or shuttle-based pulsed tunable CO2 laser DIAL system. Results indicate that maximum sensitivity at minimum laser energy per measurement requires multiple pulse operation with the energy per pulse selected so that the measured photon rate is approximately equal to the detector IF bandwidth. Measurement sensitivities can be maximized and interference effects minimized by fine adjustment of measurement frequencies using the tunability of high pressure lasers. The use of rare isotope lasers minimizes loss due to CO2 atmospheric absorption.

  5. Measurement of Turbulent Water Vapor Fluxes from Lightweight Unmanned Aircraft Systems

    NASA Astrophysics Data System (ADS)

    Thomas, R. M.; Ramanathan, V.; Nguyen, H.; Lehmann*, K.

    2010-12-01

    Scientists at the Center for Clouds, Chemistry and Climate (C4) at the Scripps Institution of Oceanography have successfully used Unmanned Aircraft Systems (UASs) for measurements of radiation fluxes, aerosol concentrations and cloud microphysical properties. Building on this success, a payload to measure water vapor fluxes using the eddy covariance (EC) technique has been recently developed and tested. To our knowledge this is the first UAS turbulent flux system to incorporate high-frequency water vapor measurements. The driving aim of the water vapor flux system’s development is to investigate ‘atmospheric rivers’ in the north-western Pacific Ocean, these can lead to sporadic yet extreme rainfall and flooding events upon landfall in California. Such a flux system may also be used to investigate other weather events (e.g. the formation of hurricanes) and offers a powerful aerosol-cloud-radiative forcing investigative tool when combined with the existing aerosol/radiation and cloud microphysics UAS payloads. The atmospheric vertical wind component (w) is derived by this system at up to 100Hz using data from a GPS/Inertial Measurement Unit (GPS/IMU) combined with a fast-response gust probe mounted on the UAV. Measurements of w are then combined with equally high frequency water vapor data (collected using a Campbell Scientific Krypton Hygrometer) to calculate latent heat fluxes (λE). Two test flights were conducted at the NASA Dryden test facility on 27th May 2010, located in the Mojave Desert. Horizontal flight legs were recorded at four altitudes between 1000-2500 masl within the convective boundary layer. Preliminary data analysis indicates averaged spectral data follow the theoretical -5/3 slope , and extrapolation of the flux profile to the surface resulted in λE of 1.6 W m-2; in good agreement with 1.0 W m-2 λE measured by NOAA from a surface tower using standard flux techniques. The system performance during the Dryden test, as well as subsequent

  6. Aircraft detection from VHR images based on circle-frequency filter and multilevel features.

    PubMed

    Gao, Feng; Xu, Qizhi; Li, Bo

    2013-01-01

    Aircraft automatic detection from very high-resolution (VHR) images plays an important role in a wide variety of applications. This paper proposes a novel detector for aircraft detection from very high-resolution (VHR) remote sensing images. To accurately distinguish aircrafts from background, a circle-frequency filter (CF-filter) is used to extract the candidate locations of aircrafts from a large size image. A multi-level feature model is then employed to represent both local appearance and spatial layout of aircrafts by means of Robust Hue Descriptor and Histogram of Oriented Gradients. The experimental results demonstrate the superior performance of the proposed method.

  7. Silicon Carbide Mixers Demonstrated to Improve the Interference Immunity of Radio-Based Aircraft Avionics

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.

    1998-01-01

    Concern over the interference of stray radiofrequency (RF) emissions with key aircraft avionics is evident during takeoff and landing of every commercial flight when the flight attendant requests that all portable electronics be switched off. The operation of key radio-based avionics (such as glide-slope and localizer approach instruments) depends on the ability of front-end RF receivers to detect and amplify desired information signals while rejecting interference from undesired RF sources both inside and outside the aircraft. Incidents where key navigation and approach avionics malfunction because of RF interference clearly represent an increasing threat to flight safety as the radio spectrum becomes more crowded. In an initial feasibility experiment, the U.S. Army Research Laboratory and the NASA Lewis Research Center recently demonstrated the strategic use of silicon carbide (SiC) semiconductor components to significantly reduce the susceptibility of an RF receiver circuit to undesired RF interference. A pair of silicon carbide mixer diodes successfully reduced RF interference (intermodulation distortion) in a prototype receiver circuit by a factor of 10 (20 dB) in comparison to a pair of commercial silicon-based mixer diodes.

  8. Aircraft IR/acoustic detection evaluation. Volume 2: Development of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft

    NASA Technical Reports Server (NTRS)

    Kraft, Robert E.

    1992-01-01

    The design and performance of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft is described and specified. The acoustic detection system performance criteria will subsequently be used to determine target detection ranges for the subject contract. Although the defined system has never been built and demonstrated in the field, the design parameters were chosen on the basis of achievable technology and overall system practicality. Areas where additional information is needed to substantiate the design are identified.

  9. Bias corrections of GOSAT SWIR XCO2 and XCH4 with TCCON data and their evaluation using aircraft measurement data

    NASA Astrophysics Data System (ADS)

    Inoue, Makoto; Morino, Isamu; Uchino, Osamu; Nakatsuru, Takahiro; Yoshida, Yukio; Yokota, Tatsuya; Wunch, Debra; Wennberg, Paul O.; Roehl, Coleen M.; Griffith, David W. T.; Velazco, Voltaire A.; Deutscher, Nicholas M.; Warneke, Thorsten; Notholt, Justus; Robinson, John; Sherlock, Vanessa; Hase, Frank; Blumenstock, Thomas; Rettinger, Markus; Sussmann, Ralf; Kyrö, Esko; Kivi, Rigel; Shiomi, Kei; Kawakami, Shuji; De Mazière, Martine; Arnold, Sabrina G.; Feist, Dietrich G.; Barrow, Erica A.; Barney, James; Dubey, Manvendra; Schneider, Matthias; Iraci, Laura T.; Podolske, James R.; Hillyard, Patrick W.; Machida, Toshinobu; Sawa, Yousuke; Tsuboi, Kazuhiro; Matsueda, Hidekazu; Sweeney, Colm; Tans, Pieter P.; Andrews, Arlyn E.; Biraud, Sebastien C.; Fukuyama, Yukio; Pittman, Jasna V.; Kort, Eric A.; Tanaka, Tomoaki

    2016-08-01

    We describe a method for removing systematic biases of column-averaged dry air mole fractions of CO2 (XCO2) and CH4 (XCH4) derived from short-wavelength infrared (SWIR) spectra of the Greenhouse gases Observing SATellite (GOSAT). We conduct correlation analyses between the GOSAT biases and simultaneously retrieved auxiliary parameters. We use these correlations to bias correct the GOSAT data, removing these spurious correlations. Data from the Total Carbon Column Observing Network (TCCON) were used as reference values for this regression analysis. To evaluate the effectiveness of this correction method, the uncorrected/corrected GOSAT data were compared to independent XCO2 and XCH4 data derived from aircraft measurements taken for the Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL) project, the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the Japan Meteorological Agency (JMA), the HIAPER Pole-to-Pole observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. These comparisons demonstrate that the empirically derived bias correction improves the agreement between GOSAT XCO2/XCH4 and the aircraft data. Finally, we present spatial distributions and temporal variations of the derived GOSAT biases.

  10. DC-8-based observations of aircraft CO, CH4, N2O, and H2O(g) emission indices during SUCCESS

    NASA Astrophysics Data System (ADS)

    Vay, S. A.; Anderson, B. E.; Sachse, G. W.; Collins, J. E., Jr.; Podolske, J. R.; Twohy, C. H.; Gandrud, B.; Chan, K. R.; Baughcum, S. L.; Wallio, H. A.

    We report the first measurements of CO, CH4, N2O, CO2, and H2O(g) in the exhaust trails of T-39, B-757, and DC-8 aircraft at cruise conditions. Emission indices (EI) derived from these in-situ measurements are presented. Results are in agreement with ground-based tests indicating aircraft act as a net sink for CH4 and recent airborne in-situ measurements that N2O is not an important exhaust constituent. Condensation of H2O(g) on exhaust particles resulted in EI(H2O(g)) values less than those expected from the combustion of fuel alone. Observed apparent negative EI(H2O(g)) values suggest that aircraft aerosol emissions, under unique atmospheric conditions, seed cloud formation and lead to dehydration of the exhaust-influenced air parcel. Such conditions may induce the formation of cirrus clouds from persistent contrails. Comparisons with the Boeing EMIT Code show measurement-derived CO emission index values consistent with model evaluations.

  11. Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

    NASA Technical Reports Server (NTRS)

    Zamora, L. M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300% over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were approx. 40- 60% smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq)/ and various biomass burning tracers (BBt/ across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACIs, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be approx. 0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/cu m and very high aerosol concentrations (2000- 3000/ cu cm in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 W/sq m or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic.We lastly explore evidence suggesting that numerous northern

  12. Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

    NASA Technical Reports Server (NTRS)

    Zamora, Lauren; Kahn, R. A.; Cubison, M. C.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were 50 smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq))/ and various biomass burning tracers (BBt/ across the multi-campaign dataset, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACI, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be 0.12 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/ cu m) and very high aerosol concentrations (2000-3000 cu m) in the most polluted clouds, the estimated ACI value was only 0.06. In this case, competition for water vapor by the high concentration of CCN strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease shortwave radiative flux by 2 and 4 W/sq or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly show evidence to suggest that numerous northern latitude background Aitken particles can interact with combustion particles

  13. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    NASA Astrophysics Data System (ADS)

    Zamora, L. M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 % over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ˜ 40-60 % smaller than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACIs, where ACI = (1/3) × dln(Nliq)/dln(BBt)) to be ˜ 0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content ( ˜ 0.02 g m-3) and very high aerosol concentrations (2000-3000 cm-3) in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 W m-2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly explore evidence suggesting that numerous northern

  14. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    DOE PAGES

    Zamora, Lauren M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; et al

    2016-01-21

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200–300% over the next 50–100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ~40–60% smallermore » than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol–cloud interactions (ACIs, where ACI = (1/3) × dln(Nliq)/dln(BBt)) to be ~0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (~0.02gm–3) and very high aerosol concentrations (2000–3000 cm–3) in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 Wm–2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. Furthermore, we lastly explore evidence suggesting that

  15. NO and NO2 emission ratios measured from in-use commercial aircraft during taxi and takeoff.

    PubMed

    Herndon, Scott C; Shorter, Joanne H; Zahniser, Mark S; Nelson, David D; Jayne, John; Brown, Robert C; Miake-Lye, Richard C; Waitz, Ian; Silva, Phillip; Lanni, Thomas; Demerjian, Ken; Kolb, Charles E

    2004-11-15

    In August 2001, the Aerodyne Mobile Laboratory simultaneously measured NO, NO2, and CO2 within 350 m of a taxiway and 550 m of a runway at John F. Kennedy Airport. The meteorological conditions were such that taxi and takeoff plumes from individual aircraft were clearly resolved against background levels. NO and NO2 concentrations were measured with 1 s time resolution using a dual tunable infrared laser differential absorption spectroscopy instrument, utilizing an astigmatic multipass Herriott cell. The CO2 measurements were also obtained at 1 s time resolution using a commercial non-dispersive infrared absorption instrument. Plumes were measured from over 30 individual planes, ranging from turbo props to jumbo jets. NOx emission indices were determined by examining the correlation between NOx (NO + NO2) and CO2 during the plume measurements. Several aircraft tail numbers were unambiguously identified, allowing those specific airframe/engine combinations to be determined. The resulting NOx emission indices from positively identified in-service operating airplanes are compared with the published International Civil Aviation Organization engine certification test database collected on new engines in certification test cells.

  16. Development of a multi-sensor airborne investigation platform based on an ultra-light aircraft

    NASA Astrophysics Data System (ADS)

    Herd, Rainer; Holst, Jonathan; Lay, Michael

    2013-04-01

    In the year 2012 the chair Raw Material and Natural Resource Management of Brandenburg University of Technology Cottbus, Germany started to develop, construct and assemble a multi-sensor airborne investigation system based on an ultra-light aircraft. The conceptual ideas were born several years before and triggered by the increasing demand of spatial underground information, increasing restrictions to access private property and the lack of affordable commercially operated systems for projects with small budgets. The concept of the presented system comprehends a full composite ultra-light aircraft, the Pipistrel VIRUS which combines a low minimum (65 km/h, a high crusing speed (250 km/h, a long range (1700 km) and a low noise potential. The investigation equipment which can be modified according to the investigation target comprises actually a CsI-y-spectrometer in the fuselage, 2 K-magnetometer at the wing tips and a VLF-EM-receiver underneath the tail. This configuration enables the system to operate for mineral exploration, geological mapping, detection of freshwater resources and brines and different environmental monitoring missions. The development and actual stage of the project will be presented. The first operating flight is scheduled for spring 2013.

  17. Advanced piloted aircraft flight control system design methodology. Volume 1: Knowledge base

    NASA Technical Reports Server (NTRS)

    Mcruer, Duane T.; Myers, Thomas T.

    1988-01-01

    The development of a comprehensive and electric methodology for conceptual and preliminary design of flight control systems is presented and illustrated. The methodology is focused on the design stages starting with the layout of system requirements and ending when some viable competing system architectures (feedback control structures) are defined. The approach is centered on the human pilot and the aircraft as both the sources of, and the keys to the solution of, many flight control problems. The methodology relies heavily on computational procedures which are highly interactive with the design engineer. To maximize effectiveness, these techniques, as selected and modified to be used together in the methodology, form a cadre of computational tools specifically tailored for integrated flight control system preliminary design purposes. While theory and associated computational means are an important aspect of the design methodology, the lore, knowledge and experience elements, which guide and govern applications are critical features. This material is presented as summary tables, outlines, recipes, empirical data, lists, etc., which encapsulate a great deal of expert knowledge. Much of this is presented in topical knowledge summaries which are attached as Supplements. The composite of the supplements and the main body elements constitutes a first cut at a a Mark 1 Knowledge Base for manned-aircraft flight control.

  18. Terminal-Area Aircraft Intent Inference Approach Based on Online Trajectory Clustering.

    PubMed

    Yang, Yang; Zhang, Jun; Cai, Kai-quan

    2015-01-01

    Terminal-area aircraft intent inference (T-AII) is a prerequisite to detect and avoid potential aircraft conflict in the terminal airspace. T-AII challenges the state-of-the-art AII approaches due to the uncertainties of air traffic situation, in particular due to the undefined flight routes and frequent maneuvers. In this paper, a novel T-AII approach is introduced to address the limitations by solving the problem with two steps that are intent modeling and intent inference. In the modeling step, an online trajectory clustering procedure is designed for recognizing the real-time available routes in replacing of the missed plan routes. In the inference step, we then present a probabilistic T-AII approach based on the multiple flight attributes to improve the inference performance in maneuvering scenarios. The proposed approach is validated with real radar trajectory and flight attributes data of 34 days collected from Chengdu terminal area in China. Preliminary results show the efficacy of the presented approach.

  19. Simplified Aircraft-Based Paired Approach: Concept Definition and Initial Analysis

    NASA Technical Reports Server (NTRS)

    Johnson, Sally C.; Lohr, Gary W.; McKissick, Burnell T.; Abbott, Terence S.; Geurreiro, Nelson M.; Volk, Paul

    2013-01-01

    Simplified Aircraft-based Parallel Approach (SAPA) is an advanced concept proposed by the Federal Aviation Administration (FAA) to support dependent parallel approach operations to runways with lateral spacing closer than 2500 ft. At the request of the FAA, NASA performed an initial assessment of the potential performance and feasibility of the SAPA concept, including developing and assessing an operational implementation of the concept and conducting a Monte Carlo wake simulation study to examine the longitudinal spacing requirements. The SAPA concept was shown to have significant operational advantages in supporting the pairing of aircraft with dissimilar final approach speeds. The wake simulation study showed that support for dissimilar final approach speeds could be significantly enhanced through the use of a two-phased altitudebased longitudinal positioning requirement, with larger longitudinal positioning allowed for higher altitudes out of ground effect and tighter longitudinal positioning defined for altitudes near and in ground effect. While this assessment is preliminary and there are a number of operational issues still to be examined, it has shown the basic SAPA concept to be technically and operationally feasible.

  20. Terminal-Area Aircraft Intent Inference Approach Based on Online Trajectory Clustering.

    PubMed

    Yang, Yang; Zhang, Jun; Cai, Kai-quan

    2015-01-01

    Terminal-area aircraft intent inference (T-AII) is a prerequisite to detect and avoid potential aircraft conflict in the terminal airspace. T-AII challenges the state-of-the-art AII approaches due to the uncertainties of air traffic situation, in particular due to the undefined flight routes and frequent maneuvers. In this paper, a novel T-AII approach is introduced to address the limitations by solving the problem with two steps that are intent modeling and intent inference. In the modeling step, an online trajectory clustering procedure is designed for recognizing the real-time available routes in replacing of the missed plan routes. In the inference step, we then present a probabilistic T-AII approach based on the multiple flight attributes to improve the inference performance in maneuvering scenarios. The proposed approach is validated with real radar trajectory and flight attributes data of 34 days collected from Chengdu terminal area in China. Preliminary results show the efficacy of the presented approach. PMID:26171417

  1. An aircraft-based case study of new particle formation and growth in the summertime Arctic

    NASA Astrophysics Data System (ADS)

    Willis, M. D.; Abbatt, J.; Burkart, J.; Bozem, H.; Koellner, F.; Schneider, J.; Hoor, P. M.; Herber, A. B.; Leaitch, W. R.

    2015-12-01

    Motivated by the changing climate of the Arctic and decreasing summer sea-ice extent, we aim to better understand how atmospheric composition will impact, or be impacted by, climate and environmental change in this region. Much attention has been paid to springtime Arctic aerosol owing to significant anthropogenic influence on this remote environment, but the cleaner, more locally influenced summertime Arctic is not well characterized. We present results of vertically resolved, particle number, aerosol size distributions, submicron aerosol composition from an aerosol mass spectrometer (AMS), and cloud condensation nuclei (CCN) concentrations from the NETCARE 2014 Polar 6 aircraft campaign. The campaign was based in the high Arctic, at Resolute Bay, Nunavut, Canada (74°N, 94°W), allowing measurements from 60 to 2900 meters over ice, open water and near the ice-edge. The focus of this case study is a new particle formation and growth event observed at the eastern end of Lancaster Sound (74°N, 81°W) on July 12, 2014 under clear sky conditions. During this flight Polar 6 travelled to the end of Lancaster Sound at 2900 m and subsequently descended to 60-70 m above the surface heading due west, with winds from the west. At the lowest altitude we observed a significant increase in particles > 4 nm, between 20 - 100 nm, and > 100 nm, indicating the presence of small particles between 4 - 20 nm and growth to larger sizes. In addition, CCN concentrations were enhanced up to ~ 200/cm3 from background levels of ≤ 100/cm3. Concurrently, the AMS indicated enhanced levels of methane sulfonic acid (MSA) and marine-like organic aerosol (OA) correlated in time with the presence of larger particles, as well as an iodide signal which correlated with the presence of small particles. These observations suggest that iodine oxides could be one contributor to particle formation, and that marine-like OA and MSA could contribute to particle growth in the summertime Arctic.

  2. Rheological Behavior of Composites Based on Carbon Fibers Recycled from Aircraft Waste

    NASA Astrophysics Data System (ADS)

    Marcaníková, Lucie; Hausnerová, Berenika; Kitano, Takeshi

    2009-07-01

    Rheological investigation of composite materials prepared from the recycled aircraft waste materials based on thermoset (epoxy/resin) matrix and long carbon fibers (CF) is presented with the aim of their utilization in consumer industry applications. The carbon fibers recovered via thermal process of pyrolysis were cut into about 150 μm length and melt mixed with thermoplastic matrices based on polypropylene (PP) and polyamide 6 (PA) and various modifiers—ethylene-ethyl acrylate-maleic anhydride (E-EA-MAH), polypropylene grafted maleic anhydride (PP-g-MA) and poly(styrene)-block-poly(ethylene-co-but-1-ene)-block-poly(styrene) (SEBS). Rheological, electrical, mechanical, thermal and morphological results revealed the composites of recycled CF and PP/PP-g-MA as well as PA/E-EA-MAH to be the most promising candidates for new applications.

  3. A high ozone episode in winter 2013 in the Uinta Basin oil and gas region characterized by aircraft measurements

    NASA Astrophysics Data System (ADS)

    Oltmans, S. J.; Karion, A.; Schnell, R. C.; Pétron, G.; Sweeney, C.; Wolter, S.; Neff, D.; Montzka, S. A.; Miller, B. R.; Helmig, D.; Johnson, B. J.; Hueber, J.

    2014-08-01

    During the winter of 2012-2013 atmospheric surface ozone mole fractions exceeded the US 8 h standard of 75 ppb on 39 days in the Uinta Basin of Utah. As part of the Uinta Basin Winter Ozone Study (UBWOS) aircraft flights were conducted throughout the basin with continuous measurements of ozone (O3), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), and discrete whole air flask samples for determination of ∼50 trace gases including a number of non-methane hydrocarbons (NMHCs). During the course of seven flights conducted between 31 January and 7 February 2013, coinciding with strong, multi-day temperature inversions, O3 levels gradually built up in the shallow boundary layer from ∼45 ppb to ∼140 ppb. Near-surface CH4 mole fractions increased during the episode from near background levels of ∼2 ppm to over 10 ppm. Based on elevated levels of CH4 across the basin and high correlations of CH4 with NMHCs from the discrete air samples, O3 precursor NMHCs were also inferred to be elevated throughout the basin. Discrete plumes of high NO2 were observed in the gas production region of the basin suggesting that gas processing plants and compressor facilities were important point sources of reactive nitrogen oxides (NOx). Vertical profiles obtained during the flights showed that the high O3 mole fractions (as well as other elevated constituents) were confined to a shallow layer from near the ground to 300-400 m above ground level (m a.g.l.) capped by a strong temperature inversion. The highest mole fractions of the measured constituents during the study period were in an isothermal cold layer that varied from ∼300 m depth on 4 February to ∼150 m on 5 February. A gradient layer with declining mole fractions with altitude extended above the isothermal layer to ∼1900 m a.s.l. (300-400 m a.g.l.) indicative of some mixing of air out of the boundary layer. O3 mole fractions continued to increase within the basin as the

  4. A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique.

    PubMed

    Shivananju, B N; Yamdagni, S; Vasu, R M; Asokan, S

    2012-12-01

    Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than ±0.1 mrad (≈0.036 mrad) and has an excellent repeatability with an error of less than 2%.

  5. A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique

    SciTech Connect

    Shivananju, B. N.; Yamdagni, S.; Vasu, R. M.; Asokan, S.

    2012-12-15

    Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than {+-}0.1 mrad ( Almost-Equal-To 0.036 mrad) and has an excellent repeatability with an error of less than 2%.

  6. Extrapolating Ground-Based Aircraft Engine Exhaust Emissions to Cruise Conditions: Lessons From the 2013 ACCESS Chase Plane Experiment

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2011-12-01

    Aircraft engine emissions constitute a tiny fraction of the global black carbon mass, but can have a disproportionate climatic impact because they are emitted high in the troposphere and in remote regions with otherwise low aerosol concentrations. Consequently, these particles are likely to strongly influence cirrus and contrail formation by acting as ice nuclei (IN). However, the ice nucleating properties of aircraft exhaust at relevant atmospheric conditions are not well known, and thus, the overall impact of aviation on cloud formation remains very uncertain. While a number of aircraft engine emissions studies have previously been conducted at sea level temperature and pressure (e.g., APEX, AAFEX-1 and 2), it unclear the extent to which exhaust emissions on the ground translate to emissions at cruise conditions with much lower inlet gas temperatures and pressures. To address this need, the NASA Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) was conducted in February-April, 2013 to examine the aerosol and gas emissions from the NASA DC-8 under a variety of different fuel types, engine power, and altitude/meteorological conditions. Two different fuel types were studied: a traditional JP-8 fuel and a 50:50 blend of JP-8 and a camelina-based hydro-treated renewable jet (HRJ) fuel. Emissions were sampled using a comprehensive suite of gas- and aerosol-phase instrumentation integrated on an HU-25 Falcon jet that was positioned in the DC-8 exhaust plume at approximately 100-500m distance behind the engines. In addition, a four-hour ground test was carried out with sample probes positioned at 30 m behind each of the inboard engines. Measurements of aerosol concentration, size distribution, soot mass, and hygroscopicity were carried out along with trace gas measurements of CO2, NO, NO2, O3, and water vapor. NOx emissions were reconciled by employing the well-established Boeing method for normalizing engine fuel flow rates to STP; however, comparison

  7. Extrapolating Ground-Based Aircraft Engine Exhaust Emissions to Cruise Conditions: Lessons From the 2013 ACCESS Chase Plane Experiment

    NASA Astrophysics Data System (ADS)

    Moore, R.; Shook, M.; Thornhill, K. L.; Winstead, E.; Anderson, B. E.

    2013-12-01

    Aircraft engine emissions constitute a tiny fraction of the global black carbon mass, but can have a disproportionate climatic impact because they are emitted high in the troposphere and in remote regions with otherwise low aerosol concentrations. Consequently, these particles are likely to strongly influence cirrus and contrail formation by acting as ice nuclei (IN). However, the ice nucleating properties of aircraft exhaust at relevant atmospheric conditions are not well known, and thus, the overall impact of aviation on cloud formation remains very uncertain. While a number of aircraft engine emissions studies have previously been conducted at sea level temperature and pressure (e.g., APEX, AAFEX-1 and 2), it unclear the extent to which exhaust emissions on the ground translate to emissions at cruise conditions with much lower inlet gas temperatures and pressures. To address this need, the NASA Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) was conducted in February-April, 2013 to examine the aerosol and gas emissions from the NASA DC-8 under a variety of different fuel types, engine power, and altitude/meteorological conditions. Two different fuel types were studied: a traditional JP-8 fuel and a 50:50 blend of JP-8 and a camelina-based hydro-treated renewable jet (HRJ) fuel. Emissions were sampled using a comprehensive suite of gas- and aerosol-phase instrumentation integrated on an HU-25 Falcon jet that was positioned in the DC-8 exhaust plume at approximately 100-500m distance behind the engines. In addition, a four-hour ground test was carried out with sample probes positioned at 30 m behind each of the inboard engines. Measurements of aerosol concentration, size distribution, soot mass, and hygroscopicity were carried out along with trace gas measurements of CO2, NO, NO2, O3, and water vapor. NOx emissions were reconciled by employing the well-established Boeing method for normalizing engine fuel flow rates to STP; however, comparison

  8. The atmospheric effects of stratospheric aircraft. Report of the 1992 Models and Measurements Workshop. Volume 1: Workshop objectives and summary

    NASA Technical Reports Server (NTRS)

    Prather, Michael J. (Editor); Remsburg, Ellis E. (Editor)

    1993-01-01

    This Workshop on Stratospheric Models and Measurements (M&M) marks a significant expansion in the history of model intercomparisons. It provides a foundation for establishing the credibility of stratospheric models used in environmental assessments of chlorofluorocarbons, aircraft emissions, and climate-chemistry interactions. The core of the M&M comparisons involves the selection of observations of the current stratosphere (i.e., within the last 15 years): these data are believed to be accurate and representative of certain aspects of stratospheric chemistry and dynamics that the models should be able to simulate.

  9. The atmospheric effects of stratospheric aircraft. Report of the 1992 Models and Measurements Workshop. Volume 3: Special diagnostic studies

    NASA Technical Reports Server (NTRS)

    Prather, Michael J. (Editor); Remsberg, Ellis E. (Editor)

    1993-01-01

    This Workshop on Stratospheric Models and Measurements (M&M) marks a significant expansion in the history of model intercomparisons. It provides a foundation for establishing the credibility of stratospheric models used in environmental assessments of chlorofluorocarbons, aircraft emissions, and climate-chemistry interactions. The core of the M&M comparisons involves the selection of observations of the current stratosphere (i.e., within the last 15 years): these data are believed to be accurate and representative of certain aspects of stratospheric chemistry and dynamics that the models should be able to simulate.

  10. Aircraft gas-turbine engines: Noise reduction and vibration control. (Latest citations from Information Services in Mechanical Engineering data base). Published Search

    SciTech Connect

    Not Available

    1992-06-01

    The bibliography contains citations concerning the design and analysis of aircraft gas turbine engines with respect to noise and vibration control. Included are studies regarding the measurement and reduction of noise at its source, within the aircraft, and on the ground. Inlet, nozzle and core aerodynamic studies are cited. Propfan, turbofan, turboprop engines, and applications in short take-off and landing (STOL) aircraft are included. (Contains a minimum of 202 citations and includes a subject term index and title list.)

  11. Performance Evaluation of Individual Aircraft Based Advisory Concept for Surface Management

    NASA Technical Reports Server (NTRS)

    Gupta, Gautam; Malik, Waqar; Tobias, Leonard; Jung, Yoon; Hong, Ty; Hayashi, Miwa

    2013-01-01

    Surface operations at airports in the US are based on tactical operations, where departure aircraft primarily queue up and wait at the departure runways. NASA's Spot And Runway Departure Advisor (SARDA) tool was developed to address these inefficiencies through Air Traffic Control Tower advisories. The SARDA system is being updated to include collaborative gate hold, either tactically or strategically. This paper presents the results of the human-in-the-loop evaluation of the tactical gate hold version of SARDA in a 360 degree simulated tower setting. The simulations were conducted for the east side of the Dallas/Fort Worth airport. The new system provides gate hold, ground controller and local controller advisories based on a single scheduler. Simulations were conducted with SARDA on and off, the off case reflecting current day operations with no gate hold. Scenarios based on medium (1.2x current levels) and heavy (1.5x current levels) traffic were explored. Data collected from the simulation was analyzed for runway usage, delay for departures and arrivals, and fuel consumption. Further, Traffic Management Initiatives were introduced for a subset of the aircraft. Results indicated that runway usage did not change with the use of SARDA, i.e., there was no loss in runway throughput as compared to baseline. Taxiing delay was significantly reduced with the use of advisory by 45% in medium scenarios and 60% in heavy. Arrival delay was unaffected by the use of advisory. Total fuel consumption was also reduced by 23% in medium traffic and 33% in heavy. TMI compliance appeared unaffected by the advisory

  12. Performance Evaluation of SARDA: An Individual Aircraft-Based Advisory Concept for Surface Management

    NASA Technical Reports Server (NTRS)

    Jung, Yoon; Malik, Waqar; Tobias, Leonard; Gupta, Gautam; Hoang, Ty; Hayashi, Miwa

    2015-01-01

    Surface operations at airports in the US are based on tactical operations, where departure aircraft primarily queue up and wait at the departure runways. NASAs Spot And Runway Departure Advisor (SARDA) tool was developed to address these inefficiencies through Air Traffic Control Tower advisories. The SARDA system is being updated to include collaborative gate hold, either tactically or strategically. This paper presents the results of the human-in-the-loop evaluation of the tactical gate hold version of SARDA in a 360 degree simulated tower setting. The simulations were conducted for the east side of the Dallas-Fort Worth airport. The new system provides gate hold, ground controller and local controller advisories based on a single scheduler. Simulations were conducted with SARDA on and off, the off case reflecting current day operations with no gate hold. Scenarios based on medium (1.2x current levels) and heavy (1.5x current levels) traffic were explored. Data collected from the simulation was analyzed for runway usage, delay for departures and arrivals, and fuel consumption. Further, Traffic Management Initiatives were introduced for a subset of the aircraft. Results indicated that runway usage did not change with the use of SARDA, i.e., there was no loss in runway throughput as compared to baseline. Taxiing delay was significantly reduced with the use of advisory by 45 in medium scenarios and 60 in heavy. Arrival delay was unaffected by the use of advisory. Total fuel consumption was also reduced by 23 in medium traffic and 33 in heavy. TMI compliance appeared unaffected by the advisory.

  13. Cosmic ray measurements at aircraft altitudes and comparison with predictions of computer codes.

    PubMed

    Zhou, D; O'Sullivan, D; Xu, B; Flood, E

    2003-01-01

    Extensive measurements of dose exposure of aircrew have been carried out in recent years using passive detectors on subsonic and supersonic air routes by DIAS (Dublin Institute for Advanced Studies). Studies were based on measurement of LET spectra using nuclear recoils produced in CR-39 nuclear track detectors by high energy neutrons and protons. The detectors were calibrated using energetic heavy ions. Data obtained were compared with the predictions of the EPCARD and CARI-6 codes. Good agreement has been found between the experimental and theoretical values.

  14. A UT/LS ozone climatology of the nineteen seventies deduced from the GASP aircraft measurement program

    NASA Astrophysics Data System (ADS)

    Schnadt Poberaj, C.; Staehelin, J.; Brunner, D.; Thouret, V.; Mohnen, V.

    2007-11-01

    We present ozone measurements of the Global Atmospheric Sampling Program (GASP) performed from four commercial and one research aircraft in the late 1970s. The GASP quality assurance and control program was reviewed, and an ozone climatology of the upper troposphere and lower stratosphere (UT/LS) of the years 1975-1979 was built. The data set was estimated to have an overall uncertainty of 9% or 3 ppb whichever is greater for the first two years and 4% or 3 ppb for the remaining years, i.e. after implementation of silicone rubber membranes in the pumps. Two cases of nearly coincident flights of two GASP airliners along the same flight route, and the comparison with independent observations from the literature, including ozonesondes and aircraft campaigns, indicate that the ozone measurements are of high quality. The UT/LS climatology of the GASP data set is in general agreement with that derived from MOZAIC in the 1990s in regions covered by both programmes. GASP provides unique large-scale climatological information on UT/LS ozone above the northern hemisphere Pacific region, which is not covered by MOZAIC. There, the GASP climatology confirms several characteristic features derived from individual research aircraft campaigns and from ozone soundings. In particular, summertime ozone in the UT over the midlatitude eastern Pacific Ocean was significantly lower in the 1970s than over the American continent. The generally lower ozone concentrations in the tropics near the dateline as compared to farther east are indicative of convective uplifting of ozone poor air from the marine boundary layer.

  15. TOMS Validation Based on Profiles of Aerosol Properties in the Lower Troposphere as Obtained with Light Aircraft Systems

    NASA Technical Reports Server (NTRS)

    Prospero, Joseph M.; Maring, Hal; Savoie, Dennis

    2003-01-01

    The goal of the University of Miami Aerosol Group (UMAG) in this project was to make measurements of vertical profiles of aerosol properties and aerosol optical depth using a light aircraft. The UMAG developed a light aircraft aerosol package (LAAP) that was used in light aircraft (Cessna 172) during the Puerto Rico Dust Experiment (PRIDE). This field campaign took place on Puerto Rico during July 2000. Design details and results from the use of the LAAP were presented at TOMS Science team meetings on April 1998, April 1999, and May 2000. Results from the LAAP collected during the PRIDE Experiment were presented at the Fall Meeting of the American Geophysical Union, December 2000. Some of the results from the LAAP collected during the PRIDE Experiment have been accepted for publication in the Journal of Geophysical Research in a "topical section" made up of papers from the PRIDE Program.

  16. Tree attenuation at 869 MHz derived from remotely piloted aircraft measurements

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Goldhirsh, Julius

    1986-01-01

    Attenuation due to single trees is experimentally investigated using UHF transmissions at 869 MHz between a remotely piloted aircraft and a ground receiver system located in a stationary vehicle. Single trees of each tree type in full foliage were found to attenuate from 10-20 dB, with an average median value of about 12 dB. Attenuation coefficients associated with path lengths through the foliage may on average be about 1 dB/m, with maximum values closer to 2 dB/m.

  17. Airborne measurements of CO2 and CH4 onboard the UK FAAM research aircraft using a, Los Gatos Research Inc, cavity enhanced absorption spectrometer

    NASA Astrophysics Data System (ADS)

    O'Shea, S.; Bauguitte, S.; Muller, J. B.; Le Breton, M.; Gallagher, M. W.; Allen, G.; Percival, C. J.

    2012-12-01

    Airborne measurements of CO2 and CH4 have been made using the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft since spring 2011.The measurement system uses a commercially available analyser, based on the off-axis integrated cavity output spectroscopy technique, from Los Gatos Research Inc (FGGA, Model RMT-200). During the first year of operation (29 flights), 1 Hz measurements were found to be accurate to 0.07 ± 2.48ppbv for CH4 and -0.06± 0.66ppmv for CO2. In summer 2011, as part of the BORTAS project (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites), outflow from boreal forest fires was measured in Eastern Canada. A number of fresh and photochemically-aged plumes were identified using simultaneous HCN measurements, a widely used tracer for biomass burning. In the freshest plumes, strong relationships were found between CH4, CO2 and other tracers for biomass burning. From this we were able to estimate that 6.9±0.8 g of CH4 and 1551±213 g of CO2 were released into the atmosphere per kg of dry matter burnt. These emission factors are in good agreement with estimates from previous studies in boreal regions. However for aged plumes the correlations between CH4 and other biomass burning tracers were not as robust, most likely due to mixing from other CH4 emission sources, such as the wetland regions. The role of additional emission sources will be investigated using the UK Met Office NAME atmospheric dispersion model and the HYSPLIT trajectory model. Using tailored back trajectory analysis, we will present an interpretation of this new dataset in the context of air mass/fire origin, relating this to MODIS fire maps and source strength.

  18. Aircraft trace gas measurements during the London 2012 Olympics: Air quality and emission fluxes derived from sampling upwind and downwind of a megacity

    NASA Astrophysics Data System (ADS)

    Allen, G.; O'Shea, S.; Muller, J.; Jones, B.; O'Sullivan, D.; Lee, J. D.; Bauguitte, S.; Gallagher, M. W.; Percival, C.; Barratt, B.; McQuaid, J. B.; Illingworth, S.

    2013-12-01

    This study presents airborne in situ and remote sensing measurements recorded during July and August 2012, across the period of the London 2012 Summer Olympics and simultaneous with the Clear air for London (ClearfLo) ground-based measurement and modelling campaign. Through long-term (2-year) and intensive observation periods (Winter 2011 and Summer 2012), the ClearfLo programme aims to better understand emissions, as well as the chemical, dynamical and micro-meteorological processes which modulate air quality in the London urban environment - an important risk factor for both acute and chronic health effects. The work presented here focuses on two contrasting case studies within the summer ClearfLo period: 30 July 2012 and 9 August 2012, representing relatively clean background and polluted background cases, respectively, and characterised by well-mixed Atlantic westerly maritime inflow in the former and stagnant air (high pressure) in the latter. Measurements of CO, CO2, CH4, N2O, O3, HCN, and other gases measured on board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 aircraft will be presented and interpreted, with emphasis on observed concentration gradients and tracer-tracer correlations as well as airmass vertical structure and airmass history upwind and downwind of central London in each case. By applying a simple advective model and making use of vertically resolved thermodynamic and composition data, we are able to derive emission strengths for these gases that are representative of the total enclosed surface area. Example emissions for these two cases range between 6x105 kg(C)/hr and 9x105 kg(C)/hr for CO2, and ~0.6x105 kg(C)/hr for CH4. This airborne sampling methodology highlights the unique utility of aircraft measurements to routinely and climatologically characterise emissions from area sources such as cities, and points to future missions to target localised hotspots and distributed point sources.

  19. Relative receiver autonomous integrity monitoring for future GNSS-based aircraft navigation

    NASA Astrophysics Data System (ADS)

    Gratton, Livio Rafael

    The Global Positioning System (GPS) has enabled reliable, safe, and practical aircraft positioning for en-route and non-precision phases of flight for more than a decade. Intense research is currently devoted to extending the use of Global Navigation Satellite Systems (GNSS), including GPS, to precision approach and landing operations. In this context, this work is focused on the development, analysis, and verification of the concept of Relative Receiver Autonomous Integrity Monitoring (RRAIM) and its potential applications to precision approach navigation. RRAIM fault detection algorithms are developed, and associated mathematical bounds on position error are derived. These are investigated as possible solutions to some current key challenges in precision approach navigation, discussed below. Augmentation systems serving continent-size areas (like the Wide Area Augmentation System or WAAS) allow certain precision approach operations within the covered region. More and better satellites, with dual frequency capabilities, are expected to be in orbit in the mid-term future, which will potentially allow WAAS-like capabilities worldwide with a sparse ground station network. Two main challenges in achieving this goal are (1) ensuring that navigation fault detection functions are fast enough to alert worldwide users of hazardously misleading information, and (2) minimizing situations in which navigation is unavailable because the user's local satellite geometry is insufficient for safe position estimation. Local augmentation systems (implemented at individual airports, like the Local Area Augmentation System or LAAS) have the potential to allow precision approach and landing operations by providing precise corrections to user-satellite range measurements. An exception to these capabilities arises during ionospheric storms (caused by solar activity), when hazardous situations can exist with residual range errors several orders of magnitudes higher than nominal. Until dual

  20. Moving-Base Simulation Evaluation of Control/Display Integration Issues for ASTOVL Aircraft

    NASA Technical Reports Server (NTRS)

    Franklin, James A.

    1997-01-01

    A moving-base simulation has been conducted on the Vertical Motion Simulator at Ames Research Center using a model of an advanced, short takeoff and vertical landing (STOVL) lift fan fighter aircraft. This experiment expanded on investigations during previous simulations with this STOVL configuration with the objective of evaluating (1) control law modifications over the low speed flight envelope, (2) integration of the throttle inceptor with flight control laws that provide direct thrust command for conventional flight, vertical and short takeoff, and flightpath or vertical velocity command for transition, hover, and vertical landing, (3) control mode blending for pitch, roll, yaw, and flightpath control during transition from wing-borne to jet-borne flight, and (4) effects of conformal versus nonconformal presentation of flightpath and pursuit guidance symbology on the out-the-window display for low speed STOVL operations. Assessments were made for takeoff, transition, hover, and landing, including precision hover and landing aboard an LPH-type amphibious assault ship in the presence of winds and rough seas. Results yielded Level 1 pilot ratings for the flightpath and vertical velocity command modes for a range of land-based and shipboard operation and were consistent with previous experience with earlier control laws and displays for this STOVL concept. Control mode blending was performed over speed ranges in accord with the pilot's tasks and with the change of the basic aircraft's characteristics between wing-borne and hover flight. Blending of yaw control from heading command in hover to sideslip command in wing-borne flight performed over a broad speed range helped reduce yaw transients during acceleration through the low speed regime. Although the pilots appreciated conformality of flightpath and guidance symbols with the external scene during the approach, increased sensitivity of the symbols for lateral path tracking elevated the pilots' control activity

  1. Drop size distributions and related properties of fog for five locations measured from aircraft

    NASA Technical Reports Server (NTRS)

    Zak, J. Allen

    1994-01-01

    Fog drop size distributions were collected from aircraft as part of the Synthetic Vision Technology Demonstration Program. Three west coast marine advection fogs, one frontal fog, and a radiation fog were sampled from the top of the cloud to the bottom as the aircraft descended on a 3-degree glideslope. Drop size versus altitude versus concentration are shown in three dimensional plots for each 10-meter altitude interval from 1-minute samples. Also shown are median volume radius and liquid water content. Advection fogs contained the largest drops with median volume radius of 5-8 micrometers, although the drop sizes in the radiation fog were also large just above the runway surface. Liquid water content increased with height, and the total number of drops generally increased with time. Multimodal variations in number density and particle size were noted in most samples where there was a peak concentration of small drops (2-5 micrometers) at low altitudes, midaltitude peak of drops 5-11 micrometers, and high-altitude peak of the larger drops (11-15 micrometers and above). These observations are compared with others and corroborate previous results in fog gross properties, although there is considerable variation with time and altitude even in the same type of fog.

  2. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft

    NASA Technical Reports Server (NTRS)

    Starke, E. A., Jr. (Editor)

    1995-01-01

    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  3. Aircraft measurements of electrified clouds at Kennedy Space Center. Part 2: Case study: 4 November 1988 (88309)

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.

    1990-01-01

    During the fall of 1988, a Schweizer airplane equipped to measure electric field and other meteorological parameters flew over Kennedy Space Center (KSC) in a program to study clouds defined in the existing launch restriction criteria. A case study is presented of a single flight over KSC on November 4, 1988. This flight was chosen for two reasons: (1) the clouds were weakly electrified, and no lightning was reported during the flight; and (2) electric field mills in the surface array at KSC indicated field strengths greater than 3 kV/m, yet the aircraft flying directly over them at an altitude of 3.4 km above sea level measured field strengths of less than 1.6 kV/m. A weather summary, sounding description, record of cloud types, and an account of electric field measurements are included.

  4. Cable Tensiometer for Aircraft

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark (Inventor)

    2008-01-01

    The invention is a cable tensiometer that can be used on aircraft for real-time, in-flight cable tension measurements. The invention can be used on any aircraft cables with high precision. The invention is extremely light-weight, hangs on the cable being tested and uses a dual bending beam design with a high mill-volt output to determine tension.

  5. Measurement of OH, H2SO4, MSA, DMSO, DMSO2 on the NASA P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, F. L.

    1998-01-01

    This project involves the deployment of a variety of unique aircraft measurements for the PEM-Tropics program. These measurements were all to be accomplished on a near simultaneous basis using a two channel selected ion chemical ionization mass spectrometer instrument. The first year of this project consisted of four components; improve and perform additional testing of the OH, H2SO4, and MSA instrument which had only flown on one previous mission (ACE-I); develop and test the vacuum and electronic hardware and software which would allow two independent mass spectrometer systems to be operated from a single instrument (one vacuum/pumping system); construct an aircraft compatible DMSO/DMS02 ion source and calibration system; and operate the above system on the NASA P-3B during PEM-Tropics. The first two of the components were to be accomplished at NCAR. The third component was to be completed at Georgia Tech and the fourth was to be conducted by researchers from both institutions on the NASA P-3B.

  6. Aircraft measurements of electrified clouds at Kennedy Space Center, part 3

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.; Fleischhacker, P.

    1990-01-01

    Flights made by the Special Purpose Test Vehicle for Atmospheric Research (SPTVAR) airplane during a second deployment to Florida during the summer of 1989 are discussed. The findings based on the data gathered are presented. The progress made during the second year of the project is discussed. The summer 1989 study was carried out with the support and guidance of Col. John Madura, Commander of Detachment 11, 2nd Weather Squadron, USAF, at Patrick Air Force Base (PAFB) and Cape Canaveral Air Force Station. The project goals were to develop and demonstrate techniques for measuring the electric field aloft and locating regions of charge during flight within and near clouds; to characterize the electric conditions that are presently identified as a threat to space launch vehicles; and to study the correlation between the electric field aloft and that at Kennedy Space Center's ground-based electric field mill array for a variety of electrified clouds.

  7. Laser beacon system for aircraft collision hazard determination.

    PubMed

    Miles, R B

    1980-07-01

    A laser beacon collision hazard determination system is capable of simultaneously determining range, bearing, and heading of threat aircraft. Calculations demonstrate that threat aircraft may be observed at > 10 km under good visibility conditions. When the visibility is limited to 5.6 km (3 nautical miles), the shortest possible warning time for aircraft below 3000 m (10,000 ft) can be > 15 sec. A wide variety of detection systems may be chosen based on cost, detection range, and sophistication. Traffic saturation is not a problem since closer aircraft produce easily distinguishable signals so traffic may be prioritized. Preliminary tests demonstrate that accurate range measurements are possible under daylight conditions.

  8. Directional monitoring terminal for aircraft noise

    NASA Astrophysics Data System (ADS)

    Genescà, M.

    2016-07-01

    This paper presents a concept of an aircraft noise monitoring terminal (NMT) that reduces background noise and the influence of ground reflection, in comparison with a single microphone. Also, it automatically identifies aircraft sound events based on the direction of arrival of the sound rather than on the sound pressure level (or radar data). And moreover, it provides an indicator of the quality of the sound pressure level measurement, i.e. if it is possibly disturbed by extraneous sources. The performance of this NMT is experimentally tested under real conditions in a measurement site close to Zurich airport. The results show that the NMT unambiguously identifies the noise events generated by the target aircraft, correctly detects those aircraft noise events that may be disturbed by the presence of other sources, and offers a substantial reduction in background and ground reflected sound.

  9. Remote sensing of potential aircraft icing areas

    NASA Astrophysics Data System (ADS)

    Zuev, Vladimir V.; Nakhtigalova, Daria P.; Shelekhov, Alexander P.; Shelekhova, Evgeniya A.; Baranov, Nikolay A.; Kizhner, Lubov I.

    2015-11-01

    Remote sensing technique of detection of potential aircraft icing areas based on temperature profile measurements, using meteorological temperature profiler, and the data of the Airfield Measuring and Information System (AMIS-RF), was proposed, theoretically described and experimentally validated during the field project in 2012 - 2013 in the Tomsk Bogashevo Airport. Spatial areas of potential aircraft icing were determined using the RAP algorithm and Godske formula. The equations for the reconstruction of profiles of relative humidity and dew point using data from AMIS-RF are given. Actual data on the aircraft icing for the Tomsk Bogashevo Airport on 11 October 2012 and 17 March 2013 are presented in this paper. The RAP algorithm and Godske formula show similar results for the location of spatial areas of potential icing. Though, the results obtained using the RAP algorithm are closer to the actual data on the icing known from aircraft crew reports.

  10. Handling Qualities Prediction of an F-16XL-Based Reduced Sonic Boom Aircraft

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce; Yoo, Seung

    2010-01-01

    A major goal of the Supersonics Project under NASA s Fundamental Aeronautics program is sonic boom reduction of supersonic aircraft. An important part of this effort is development and validation of sonic boom prediction tools used in aircraft design. NASA Dryden s F- 16XL was selected as a potential testbed aircraft to provide flight validation. Part of this task was predicting the handling qualities of the modified aircraft. Due to the high cost of modifying the existing F-16XL control laws, it was desirable to find modifications that reduced the aircraft sonic boom but did not degrade baseline aircraft handling qualities allowing for the potential of flight test without changing the current control laws. This was not a requirement for the initial modification design work, but an important consideration for proceeding to the flight test option. The primary objective of this work was to determine an aerodynamic and mass properties envelope of the F-16XL aircraft. The designers could use this envelope to determine the effect of proposed modifications on aircraft handling qualities.

  11. Analysis of Satellite-Derived Arctic Tropospheric BrO Columns in Conjunction with Aircraft Measurements During ARCTAS and ARCPAC

    NASA Technical Reports Server (NTRS)

    Choi, S.; Wang, Y.; Salawitch, R. J.; Canty, T.; Joiner, J.; Zeng, T.; Kurosu, T. P.; Chance, K.; Richter, A.; Huey, L. G.; Liao, J.; Neuman, J. A.; Nowak, J. B.; Dibb, J. E.; Weinheimer, A. J.; Diskin, G.; Ryerson, T. B.; da Silva, A.; Curry, J.; Kinnison, D.; Tilmes, S.; Levelt, P. F.

    2012-01-01

    We derive tropospheric column BrO during the ARCTAS and ARCPAC field campaigns in spring 2008 using retrievals of total column BrO from the satellite UV nadir sensors OMI and GOME-2 using a radiative transfer model and stratospheric column BrO from a photochemical simulation. We conduct a comprehensive comparison of satellite-derived tropospheric BrO column to aircraft in-situ observations ofBrO and related species. The aircraft profiles reveal that tropospheric BrO, when present during April 2008, was distributed over a broad range of altitudes rather than being confined to the planetary boundary layer (PBL). Perturbations to the total column resulting from tropospheric BrO are the same magnitude as perturbations due to longitudinal variations in the stratospheric component, so proper accounting of the stratospheric signal is essential for accurate determination of satellite-derived tropospheric BrO. We find reasonably good agreement between satellite-derived tropospheric BrO and columns found using aircraft in-situ BrO profiles, particularly when satellite rad