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  • 1
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    Piloted Simulation to Evaluate the Utility of a Real Time Envelope Protection System for Mitigating In-Flight Icing Hazards (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The utility of the Icing Contamination Envelope Protection (ICEPro) system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device (ICEFTD). ICEPro provides real time envelope protection cues and alerting messages on pilot displays. The pilots participating in this test were divided into two groups; a control group using baseline displays without ICEPro, and an experimental group using ICEPro driven display cueing. Each group flew identical precision approach and missed approach procedures with a simulated failure case icing condition. Pilot performance, workload, and survey questionnaires were collected for both groups of pilots. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their situation awareness of a hazardous aircraft state.
    Keywords: Air Transportation and Safety
    Type: NASA/TM-2011-216951 , AIAA Paper 2010-7987 , E-17556 , Atmospheric and Space Environments Conference; Aug 02, 2010 - Aug 05, 2010; Toronto, Ontario; Canada
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Flight Test Results of a GPS-Based Pitot-Static Calibration Method Using Output-Error Optimization for a Light Twin-Engine Airplane (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: As part of the NASA Aviation Safety Program (AvSP), a novel pitot-static calibration method was developed to allow rapid in-flight calibration for subscale aircraft while flying within confined test areas. This approach uses Global Positioning System (GPS) technology coupled with modern system identification methods that rapidly computes optimal pressure error models over a range of airspeed with defined confidence bounds. This method has been demonstrated in subscale flight tests and has shown small 2- error bounds with significant reduction in test time compared to other methods. The current research was motivated by the desire to further evaluate and develop this method for full-scale aircraft. A goal of this research was to develop an accurate calibration method that enables reductions in test equipment and flight time, thus reducing costs. The approach involved analysis of data acquisition requirements, development of efficient flight patterns, and analysis of pressure error models based on system identification methods. Flight tests were conducted at The University of Tennessee Space Institute (UTSI) utilizing an instrumented Piper Navajo research aircraft. In addition, the UTSI engineering flight simulator was used to investigate test maneuver requirements and handling qualities issues associated with this technique. This paper provides a summary of piloted simulation and flight test results that illustrates the performance and capabilities of the NASA calibration method. Discussion of maneuver requirements and data analysis methods is included as well as recommendations for piloting technique.
    Keywords: Air Transportation and Safety
    Type: NF1676L-11942 , AIAA Atmospheric Flight Mechanics Conference; Aug 08, 2011 - Aug 11, 2011; Portland, OR; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 3
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    Development, Implementation, and Pilot Evaluation of a Model-Driven Envelope Protection System to Mitigate the Hazard of In-Flight Ice Contamination on a Twin-Engine Commuter Aircraft (2014)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Fatal loss-of-control accidents have been directly related to in-flight airframe icing. The prototype system presented in this report directly addresses the need for real-time onboard envelope protection in icing conditions. The combination of prior information and real-time aerodynamic parameter estimations are shown to provide sufficient information for determining safe limits of the flight envelope during inflight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system was designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. The utility of the ICEPro system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their awareness of a hazardous aircraft state. The performance of ICEPro system was further evaluated by various levels of sensor noise and atmospheric turbulence.
    Keywords: Air Transportation and Safety; Avionics and Aircraft Instrumentation; Behavioral Sciences
    Type: NASA/CR-2014-218320 , E-18918 , GRC-E-DAA-TN14427
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 4
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    Alfvenic Fluctuations Associated with Jupiter's Auroral Emissions (2019)
    In:  CASI
    Details
    Publication Date: 2019-11-14
    Description: The Alfvn wave mode transmits fieldaligned currents and largescale turbulence throughout Jupiter's magnetosphere. Magnetometer data from the Juno spacecraft have provided the first observations of Alfvnic fluctuations along the polar magnetic flux tubes connected to Jupiter's main auroral oval and the Jovian satellites. Transverse magnetic field perturbations associated with Io are observed up to ~90 away from main Io footprint, supporting the presence of extended Alfvnic wave activity throughout the Io footprint tail. Additional broadband fluctuations measured equatorward of the statistical auroral oval are composed of incompressible magnetic turbulence that maps to Jupiter's equatorial plasma sheet at radial distances within ~20 R(sub J). These fluctuations exhibit a k(sub ||) power spectrum consistent with strong magnetohydrodynamic turbulence. This turbulence can generate up to ~100 mW/m(exp 2) of Poynting flux to power the Jovian aurora in regions connected to the inner magnetosphere's central plasma sheet.
    Keywords: Lunar and Planetary Science and Exploration
    Type: GSFC-E-DAA-TN73681 , Geophysical Research Letters; 46; 13; 7157-7165
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Using Indirect Turbulence Measurements for Real-Time Parameter Estimation in Turbulent Air (2012)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The use of indirect turbulence measurements for real-time estimation of parameters in a linear longitudinal dynamics model in atmospheric turbulence was studied. It is shown that measuring the atmospheric turbulence makes it possible to treat the turbulence as a measured explanatory variable in the parameter estimation problem. Commercial off-the-shelf sensors were researched and evaluated, then compared to air data booms. Sources of colored noise in the explanatory variables resulting from typical turbulence measurement techniques were identified and studied. A major source of colored noise in the explanatory variables was identified as frequency dependent upwash and time delay. The resulting upwash and time delay corrections were analyzed and compared to previous time shift dynamic modeling research. Simulation data as well as flight test data in atmospheric turbulence were used to verify the time delay behavior. Recommendations are given for follow on flight research and instrumentation.
    Keywords: Aerodynamics
    Type: NF1676L-14091 , 2012 AIAA Guidance, Navigation, and Control Conference; Aug 13, 2012 - Aug 16, 2012; Minneapolis, MN; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 6
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    Development and Implementation of a Model-Driven Envelope Protection System for In-Flight Ice Contamination (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2011-216960 , AIAA Paper 2010-8141 , E-17565 , Guidance, Navigation, and Control Conference; Aug 02, 2010 - Aug 05, 2010; Toronto, Ontario; Canada
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Evaluation of Piloted Inputs for Onboard Frequency Response Estimation (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Frequency response estimation results are presented using piloted inputs and a real-time estimation method recently developed for multisine inputs. A nonlinear simulation of the F-16 and a Piper Saratoga research aircraft were subjected to different piloted test inputs while the short period stabilator/elevator to pitch rate frequency response was estimated. Results show that the method can produce accurate results using wide-band piloted inputs instead of multisines. A new metric is introduced for evaluating which data points to include in the analysis and recommendations are provided for applying this method with piloted inputs.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-15957 , AIAA Atmospheric Flight Mechanics Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 8
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    Flight Test Results of an Angle of Attack and Angle of Sideslip Calibration Method Using Output-Error Optimization (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: As part of a joint partnership between the NASA Aviation Safety Program (AvSP) and the University of Tennessee Space Institute (UTSI), research on advanced air data calibration methods has been in progress. This research was initiated to expand a novel pitot-static calibration method that was developed to allow rapid in-flight calibration for the NASA Airborne Subscale Transport Aircraft Research (AirSTAR) facility. This approach uses Global Positioning System (GPS) technology coupled with modern system identification methods that rapidly computes optimal pressure error models over a range of airspeed with defined confidence bounds. Subscale flight tests demonstrated small 2- error bounds with significant reduction in test time compared to other methods. Recent UTSI full scale flight tests have shown airspeed calibrations with the same accuracy or better as the Federal Aviation Administration (FAA) accepted GPS 'four-leg' method in a smaller test area and in less time. The current research was motivated by the desire to extend this method for inflight calibration of angle of attack (AOA) and angle of sideslip (AOS) flow vanes. An instrumented Piper Saratoga research aircraft from the UTSI was used to collect the flight test data and evaluate flight test maneuvers. Results showed that the output-error approach produces good results for flow vane calibration. In addition, maneuvers for pitot-static and flow vane calibration can be integrated to enable simultaneous and efficient testing of each system.
    Keywords: Aircraft Design, Testing and Performance
    Type: NF1676L-16921 , AIAA Atmospheric Flight Mechanics Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 9
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    Simulation Evaluation of Pilot Inputs for Real Time Modeling During Commercial Flight Operations (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Aircraft dynamics characteristics can only be identified from flight data when the aircraft dynamics are excited sufficiently. A preliminary study was conducted into what types and levels of manual piloted control excitation would be required for accurate Real-Time Parameter IDentification (RTPID) results by commercial airline pilots. This includes assessing the practicality for the pilot to provide this excitation when cued, and to further understand if pilot inputs during various phases of flight provide sufficient excitation naturally. An operationally representative task was evaluated by 5 commercial airline pilots using the NASA Ice Contamination Effects Flight Training Device (ICEFTD). Results showed that it is practical to use manual pilot inputs only as a means of achieving good RTPID in all phases of flight and in flight turbulence conditions. All pilots were effective in satisfying excitation requirements when cued. Much of the time, cueing was not even necessary, as just performing the required task provided enough excitation for accurate RTPID estimation. Pilot opinion surveys reported that the additional control inputs required when prompted by the excitation cueing were easy to make, quickly mastered, and required minimal training.
    Keywords: Aircraft Stability and Control
    Type: NASA/CR-2017-219600
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 10
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    Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years (2022)
    Nature Research
    Details
    Publication Date: 2024-02-07
    Description: The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
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    PAPER (OCEANREP)
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