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Modeling and Evaluating Pilot Performance in NextGen: Review of and Recommendations Regarding Pilot Modeling Efforts, Architectures, and Validation Studies
NextGen operations are associated with a variety of changes to the national airspace system (NAS) including changes to the allocation of roles and responsibilities among operators and automation, the use of new technologies and automation, additional information presented on the flight deck, and the entire concept of operations (ConOps). In the transition to NextGen airspace, aviation and air operations designers need to consider the implications of design or system changes on human performance and the potential for error. To ensure continued safety of the NAS, it will be necessary for researchers to evaluate design concepts and potential NextGen scenarios well before implementation. One approach for such evaluations is through human performance modeling. Human performance models (HPMs) provide effective tools for predicting and evaluating operator performance in systems. HPMs offer significant advantages over empirical, human-in-the-loop testing in that (1) they allow detailed analyses of systems that have not yet been built, (2) they offer great flexibility for extensive data collection, (3) they do not require experimental participants, and thus can offer cost and time savings. HPMs differ in their ability to predict performance and safety with NextGen procedures, equipment and ConOps. Models also vary in terms of how they approach human performance (e.g., some focus on cognitive processing, others focus on discrete tasks performed by a human, while others consider perceptual processes), and in terms of their associated validation efforts. The objectives of this research effort were to support the Federal Aviation Administration (FAA) in identifying HPMs that are appropriate for predicting pilot performance in NextGen operations, to provide guidance on how to evaluate the quality of different models, and to identify gaps in pilot performance modeling research, that could guide future research opportunities. This research effort is intended to help the FAA evaluate pilot modeling efforts and select the appropriate tools for future modeling efforts to predict pilot performance in NextGen operations.
Sensitivity and Validation Studies of Plutonium-238 Production with Shift and ORIGEN
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Plutonium-238 Production Sensitivity and Validation Studies Continued: Effects of Core Component Compositions
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High-Fidelity Numerical Wave Tank Verification & Validation Study: Wave Generation Through Paddle Motion
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Human visual sampling processes - A simulation validation study
Pilots and flight simulator used in study of human visual sampling study
ANOPP validation study: Lockheed L-1011
The aircraft noise prediction program (ANOPP) was used to predict the far-field noise characteristics of an L-1011 aircraft equipped with RB.211-524B engines. Actual flight noise was compared with noise predicted for the same operating and weather conditions. Correlation of predicted and measured results was very good in the aft quadrant of radiated noise. Predicted noise levels were significantly different from measured values in the forward quadrant because fan noise was predicted high. Since the major noise sources were fan and core, corrections are supplied to adjust ANOPP fan and core noise components so that the total predicted noise matches the measured L-1011 noise levels.
NASA TLA workload analysis support. Volume 2: Metering and spacing studies validation data
Four sets of graphic reports--one for each of the metering and spacing scenarios--are presented. The complete data file from which the reports were generated is also given. The data was used to validate the detail task of both the pilot and copilot for four metering and spacing scenarios. The output presents two measures of demand workload and a report showing task length and task interaction.
An assessment and validation study of nuclear reactors for low power space applications
The feasibility and safety of six conceptual small, low power nuclear reactor designs was evaluated. Feasibility evaluations included the determination of sufficient reactivity margins for seven years of full power operation and safe shutdown as well as handling during pre-launch assembly phases. Safety evaluations were concerned with the potential for maintaining subcritical conditions in the event of launch or transportation accidents. These included water immersion accident scenarios both with and without water flooding the core. Results show that most of the concepts can potentially meet the feasibility and safety requirements; however, due to the preliminary nature of the designs considered, more detailed designs will be necessary to enable these concepts to fully meet the safety requirements.
Configuration trade and code validation study on a conical hypersonic vehicle
A study has been conducted on a generic wing-cone transatmospheric vehicle at Mach numbers form 2.5 to 4.5. The objectives of the study were to experimentally define the aerodynamic characteristics of the vehicle and evaluate several computational aerodynamic prediction methods through comparison with the experimental results. The baseline wing-cone configuration fuselage consisted of a 5 deg half-angle cone forebody, cylindrical midbody, and 9 deg truncated cone afterbody. The 4-percent-thick diamond airfoil wing had an aspect ratio of 1. Several configuration variables were investigated to provide trade information on canard, wing-position and incidence, vertical tail, and nose bluntness effects. Results of the study show that wing-position and wing-incidence effects on the longitudinal aerodynamic characteristics can be significantly influenced by wing-body interference. The use of positive wing incidence to provide favorable forebody orientation for possible inlet performance improvement is accompanied by trim drag and lift-drag ratio penalties. The lateral-directional stability characteristics were strongly influenced by the location of the vertical tails. The higher-order full-potential method provided better estimates of the aerodynamic characteristics than either the linearized supersonic potential method or the tangent-cone/tangent-wedge/shock-expansion on method.
Space reactor assessment and validation study
The present difficulties experienced by the United States in launching payloads into space has suggested a number of problems which are associated with the handling of hazardous materials in spacecraft. The question has arisen as to the safety of launching highly radioactive material such as plutonium-238, related to the possibility of its dispersion into the atmosphere during a launch vehicle explosion. An alternative is the use of a small nuclear reactor which is not started until it is in space and contains little or no radioactivity at launch. A first order assessment of six small reactor concepts with power levels up to 100 MWe was performed. Both the nuclear feasibility of these concepts to operate at their rated power levels between 7 and 10 years and the capability of these concepts to remain subcritical both before and during launch and also in the case of water immersion during a potential launch failure or abort were investigated.
Experimental validation study of an analytical model of discrete frequency sound propagation in closed-test-section wind tunnels
The principal objective is to assess the adequacy of linear acoustic theory with an impedence wall boundary condition to model the detailed sound field of an acoustic source in a duct. Measurements and calculations are compared of a simple acoustic source in a rectangular concrete duct lined with foam on the walls and anechoic end terminations. Measurement of acoustic pressure for twelve wave numbers provides variation in frequency and absorption characteristics of the duct walls. Close to the source, where the interference of wall reflections is minimal, correlation is very good. Away from the source, correlation degrades, especially for the lower frequencies. Sensitivity studies show little effect on the predicted results for changes in impedance boundary condition values, source location, measurement location, temperature, and source model for variations spanning the expected measurement error.
A validation study of the Spark Navier Stokes code for nonreacting scramjet combustor flowfields
A detailed study of Mach 2 flow over a rearward facing step and staged normal injection behind a rearward facing step into a Mach 2 mainflow has been performed using the Spark three-dimensional Navier-Stokes code. Very good overall agreement was observed for the flowfield without normal injection. The notable exceptions were the velocity for which the measured values showed more scatter and the temperature at the wall for which the value measured was below the adiabatic wall temperature. Faithful representation of the incoming boundary layer was found to be important in achieving good agreement. For the staged jet case, the calculated and measured flow quantities showed reasonably good agreement, with two significant discrepancies: the calculated jet trajectory is inclined more to the vertical then the measured one, and the measured temperatures downstream of the jets are lower than the computed ones. Possible reasons for the discrepancies are suggested.
Expert system verification and validation study. Delivery 1: Survey and interview questions
The NASA funded questionnaire is presented to help define the state-of-the-practice in the formal evaluation of Expert Systems on current NASA and industry applications. The answers to this questionnaire, together with follow-up interviews, will provide realistic answers to the following questions: (1) How much evaluation is being performed; (2) What evaluation techniques are in use; and (3) What, if any, are the unique issues in evaluating Expert Systems.
Hypersonic code efficiency and validation studies
Renewed interest in hypersonic and supersonic flows spurred the development of the Compressible Navier-Stokes (CNS) code. Originally developed for external flows, CNS was modified to enable it to also be applied to internal high speed flows. In the initial phase of this study CNS was applied to both internal flow applications and fellow researchers were taught to run CNS. The second phase of this research was the development of surface grids over various aircraft configurations for the High Speed Research Program (HSRP). The complex nature of these configurations required the development of improved surface grid generation techniques. A significant portion of the grid generation effort was devoted to testing and recommending modifications to early versions of the S3D surface grid generation code.
Expert system verification and validation study: Workshop and presentation material
Workshop and presentation material are included. Following an introduction, the basic concepts, techniques, and guidelines are discussed. Handouts and worksheets are included.
Workshop report - A validation study of Navier-Stokes codes for transverse injection into a Mach 2 flow
A CFD (Computational Fluid Dynamics) competition was held at the Third Scramjet Combustor Modeling Workshop to assess the current state-of-the-art in CFD codes for the analysis of scramjet combustors. Solutions from six three-dimensional Navier-Stokes codes were compared for the case of staged injection of air behind a step into a Mach 2 flow. This case was investigated experimentally at the University of Virginia and extensive in-stream data was obtained. Code-to-code comparisons have been made with regard to both accuracy and efficiency. The turbulence models employed in the solutions are believed to be a major source of discrepancy between the six solutions.
A LIS Validation Study at the KSC-ER using LDAR and Field Mill Data
The chance of having the TRMM satellite pass over east central Florida when there is lightning over the NASA Kennedy Space Center (KSC) and USAF Eastern Range (ER) is small; however, such a condition did occur on September 21, 1998 (Day 264). Starting at about 20:40 GMT, the Lightning Imaging Sensor (LIS) reported 5 flashes during a 90 second interval that the KSC-ER was within the sensor field of view. Ground-based instrumentation, the Lightning Detection and Ranging (LDAR) system and a network of electric field mills (FM), detected 6 flashes in the same interval. In this paper, we will compare the times and locations of the optical pulses that were detected by LIS with the times and locations of RF sources (LDAR) and the charges that were deposited by the flash (FM network). We will show that LIS responded to all flashes that the LDAR and FM network detected; however, two discharges that were separated by less than 1 second in time and by about 10 km in space were grouped as one flash by the LIS data processing algorithm. In spite of the fact that all flashes occurred near the edge of the LIS field of view, the locations of the LIS events were consistent with both the LDAR and FM locations (the latter are usually within 1-2 kilometers of each other and often are co-located). Two of the 5 flashes reported by LIS were shifted north by about 8 km from the corresponding LDAR and FM locations. The LIS flash times tended to be after the first LDAR pulse was detected and before the last, and the integrated light signal (per LIS event) was surprisingly constant over the 5 flashes that were detected by LIS. In the future, we plan to study more correlated events and will try to determine whether and how the LIS light signal is related to the charge transfer in the flash and/or the number and spatial extent of RF sources.