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Committee on the Effects of Aircraft-Pilot Coupling on Flight Safety
DUANE T. McRUER (chair),
Systems Technology, Inc.
CARL S. DROSTE,
Lockheed Martin Tactical Aircraft Systems
R. JOHN HANSMAN, JR.,
Massachusetts Institute of Technology
RONALD A. HESS,
University of California–Davis
DAVID P. LeMASTER,
Wright Laboratory
STUART MATTHEWS,
Flight Safety Foundation
JOHN D. McDONNELL,
McDonnell Douglas Aerospace
JAMES McWHA,
Boeing Commercial Airplane Group
WILLIAM W. MELVIN,
Air Line Pilots Association; Delta Air Lines
(retired)
RICHARD W. PEW,
BBN Corporation
Staff
ALAN ANGLEMAN, Study Director
JOANN CLAYTON-TOWNSEND, Director,
Aeronautics and Space Engineering Board
MARY MESZAROS, Senior Project Assistant
Aeronautics and Space Engineering Board Liaison
JOHN K. BUCKNER,
Lockheed Martin Tactical Aircraft Systems
(retired)
Technical Liaisons
RALPH A'HARRAH,
National Aeronautics and Space Administration
JIM ASHLEY,
Federal Aviation Administration
DAVID L. KEY,
U.S. Army
TOM LAWRENCE,
U.S. Navy
Aeronautics and Space Engineering Board
JOHN D. WARNER (chair),
The Boeing Company, Seattle, Washington
STEVEN AFTERGOOD,
Federation of American Scientists, Washington, D.C.
GEORGE A. BEKEY,
University of Southern California, Los Angeles
GUION S. BLUFORD, JR.,
NYMA Incorporated, Brook Park, Ohio
RAYMOND S. COLLADAY,
Lockheed Martin, Denver, Colorado
BARBARA C. CORN, BC
Consulting Incorporated, Searcy, Arkansas
STEVEN D. DORFMAN,
Hughes Electronics Corp., Los Angeles, California
DONALD C. FRASER,
Boston University, Boston, Massachusetts
DANIEL HASTINGS,
Massachusetts Institute of Technology, Cambridge
FREDERICK HAUCK,
International Technology Underwriters, Bethesda, Maryland
WILLIAM H. HEISER,
United States Air Force Academy, Colorado Springs, Colorado
WILLIAM HOOVER,
U.S. Air Force
(retired),
Williamsburg, Virginia
BENJAMIN HUBERMAN,
Huberman Consulting Group, Washington, D.C.
FRANK E. MARBLE,
California Institute of Technology, Pasadena
C. JULIAN MAY,
Tech/Ops International Incorporated, Kennesaw, Georgia
GRACE M. ROBERTSON,
McDonnell Douglas, Long Beach, California
GEORGE SPRINGER,
Stanford University, Stanford, California
Staff
JOANN CLAYTON-TOWNSEND, Director
Preface
Unfavorable aircraft-pilot coupling (APC) events include a broad set of undesirable—and sometimes hazardous—phenomena that are associated with less-than-ideal interactions between pilots and aircraft. As civil and military aircraft technologies advance, pilot-aircraft interactions are becoming more complex. Recently, there have been accidents and incidents attributed to adverse APC in military aircraft. In addition, APC has been implicated in some civilian incidents. In response to this situation, and at the request of the National Aeronautics and Space Administration, the National Research Council established the Committee on the Effects of Aircraft-Pilot Coupling on Flight Safety. This committee evaluated the current state of knowledge about adverse APC and processes that may be used to eliminate it from military and commercial aircraft.
The committee analyzed the information it collected and developed a set of findings and recommendations for consideration by the U.S. Air Force, Navy, and Army; National Aeronautics and Space Administration; and Federal Aviation Administration. In particular, the committee concluded that in the short term the risk posed by adverse APC could be reduced by increased awareness of APC possibilities and more disciplined application of existing tools and capabilities throughout the development, test, and certification process. However, new approaches are also needed to address the APC risk faced by many advanced aircraft designs. In order to develop new approaches, long-term efforts are needed in the area of APC assessment criteria, analysis tools, and simulation capabilities. (See Chapter 7 for a complete list of the committee's findings and recommendations.)
The study committee met four times between September 1995 and June 1996. (See Appendix A for a list of committee members and their professional background.) To ensure that the committee's work included a broad range of perspectives, the second and third meetings included workshop presentations involving 38 outside individuals with experience in aircraft research, design, development, manufacture, test, and operations. The committee's outreach also extended internationally to France, Germany, Russia, Sweden, and the United Kingdom.
The committee wishes to thank all of its meeting participants, who are listed in Appendix B, for their contributions to the work of the committee. The committee also expresses special thanks for the assistance provided by each of its liaisons (see page iii).
DUANE T. McRUER
COMMITTEE CHAIR
Tables and Figures
TABLES
1-1a |
Single Axis PIOs Associated with Extended Rigid Body Effective Aircraft Dynamics |
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1-1b |
Single-Axis PIOs Associated with Extended Rigid Body Plus Mechanical Elaborations |
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1-1c |
Single-Axis, Higher-Frequency PIOs |
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1-1d |
Combined Three-Dimensional, Multi-Axis PIOs |
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1-2 |
Noteworthy APC Events Involving FBW Aircraft |
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2-1 |
Cross Section of Frequencies |
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4-1 |
Flying Qualities Requirements and Metrics |
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4-2 |
Suggested Tasks and Inputs for APC Evaluation |
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6-1 |
Idealized Rate-Command Controlled Element Characteristics |
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6-2 |
Prediction of PIO Susceptibility with Smith-Geddes Attitude-Dominant Type III Criterion for Operational and Test Aircraft |
FIGURES
2-2 |
Most common FCS locations of command gain shaping, rate limiters, and position limiters |
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2-3a |
Surface actuator rate limiting effects for various input amplitudes in a closed-loop surface actuator system |
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2-3b |
Surface actuator rate limiting effects for various input amplitudes showing linear system response times |
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2-3c |
Surface actuator rate limiting effects for various input amplitudes showing near saturation response times |
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2-3d |
Surface actuator rate limiting effects for various input amplitudes showing highly saturated response times |
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2-4 |
Example of command gain shaping for a nonlinear element |
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2-5 |
JAS 39 accident time history |
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2-6 |
JAS 39 accident cross plot of stick deflection in roll and pitch during a roll PIO and unintended pitch up maneuver |
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2-7 |
YF-22 accident time history |
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2-8 |
YF-22 pitch rate command stick gradients |
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2-9 |
Time history for 777 landing derotation, baseline control law |
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2-10 |
Normal mode elevator control law |
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2-11 |
Time history for 777 attitude tracking on runway, baseline control law |
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2-12 |
Time history for 777 attitude tracking on runway, secondary mode |
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2-13 |
Time history for 777 attitude tracking on runway, revised control law |
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2-14 |
Time history for 777 attitude tracking on runway, revised control law plus command filter |
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2-15 |
Bandwidth criteria applied to landing derotation, effect of 777 control law changes on pitch attitude/column position frequency response |
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2-16 |
Elevator/column gain and phase, effect of 777 control law changes on landing derotation |
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2-17 |
C-17 test aircraft lateral oscillations during approach to landing with hydraulic system #2 inoperative |
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2-18 |
C-17 test aircraft lateral oscillations during approach to landing with hydraulic system #2 inoperative, continued |
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2-19 |
A 320 incident time history |
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2-20 |
Response time analysis for the advanced digital optical control system demonstrator |
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2-21 |
Sample time history for a rotorcraft vertical landing task |
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2-22 |
Schematic drawing of a helicopter tracking a vehicle-mounted hover board |
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2-23 |
Helicopter lateral-position tracking task, velocity profile for the lateral vehicle displacement |
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2-24 |
Time history of the helicopter lateral-position tracking task with no added time delay |
2-25 |
Time history of the helicopter lateral-position tracking task with 100 msec of added time delay |
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2-26 |
Small-amplitude handling qualities criterion (target acquisition and tracking) from ADS-33D |
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4-1 |
Design process for avoiding adverse APC events |
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5-1 |
A comparison of NASA and U.S. Air Force simulators for principal piloting tasks, circa 1975 |
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5-2 |
A PIO (APC) rating scale |
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5-3 |
A comparison of PIO ratings showing normal and offset landing tasks by the NASA Flight Simulator for Advanced Aircraft (FSAA) and the U.S. Air Force Total in-Flight Simulator (TIFS) |
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5-4 |
A comparison of PIO ratings for formation-flying by the NASA Flight Simulator for Advanced Aircraft (FSAA) and the U.S. Air Force Total In-Flight Simulator (TIFS) |
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5-5 |
A comparison of PIO ratings for demanding landing tasks by the NASA Vertical Motion Simulator (VMS) and the U.S. Air Force Total In-Flight Simulator (TIFS) |
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5-6 |
A feedback system involving the human pilot |
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5-7 |
A block diagram representation of the human pilot transfer function |
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5-8 |
A block diagram of an open-loop PVS |
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5-9 |
A block diagram of a closed-loop PVS |
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6-1 |
Definitions of aircraft pitch attitude bandwidth and phase delay |
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6-2 |
Aircraft-Bandwidth/Phase Delay/Dropback requirements for PIO resistance in terminal flight phases |
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6-3 |
Aircraft-Bandwidth/Phase Delay parameters as indicators of PIO susceptibility for sample operational and test aircraft |
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6-4 |
Bode and gain phase diagram presentations for Kc e-sτ/s |
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6-5 |
Gain/Phase Template, ω180/Average Phase Rate Boundaries |
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6-6 |
Correlation between Smith-Geddes criterion frequency and Have PIO flight data |
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6-7 |
Moscow Aviation Institute PIO boundaries |
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6-8 |
Neal-Smith trends with variation of effective delay for Kc e-sτ /s |
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6-9 |
Pitch rate overshoot and pitch attitude dropback |
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6-10 |
Tentative forbidden zones for Category II PIOs |
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C-1a |
Bode and Nichols diagrams for a synchronous PVS of an aircraft with low susceptibility to oscillatory APC events |
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C-1b |
Bode and Nichols diagrams for a synchronous PVS of an aircraft with high susceptibility to oscillatory APC events |
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C-2 |
Input amplitude-dependent stability boundaries as a function of command-path gain shaping ratio for a linear system gain margin δG M = 1.5 |
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C-3 |
Time domain and transfer characteristics for fully developed rate limiting |