Systems Technology Short Courses

PILOT-INDUCED OSCILLATIONS
From the Wright Flyer to Fly-by-Wire

Pilot-Induced Oscillations (PIO) are rare, unexpected, and unintended excursions in aircraft attitude and flight path caused by anomalous interactions between the aircraft and pilot. They have occurred at some time in the development cycle for just about every new air vehicle design. Catastrophic events that lead to mishaps cost time, money, and sometimes lives. With the advent of modern flight control systems, the potential for catastrophic PIO is on the rise.

In this two-day short course, the phenomenon of PIO will be examined from its origins to today’s events. With practical examples from flight research, flight test, and operational experience, the speakers identify the myriad causes of PIO and describe the cures available to the design engineer.

The course is intended for a broad audience including program managers, controls and flight test engineers, and pilots. At the end of the course, the attendee will be familiar with:

• Causes of the most publicized PIOs
• Methods for their prevention by design and prediction by analysis
• Simulation and flight test techniques to expose PIO tendencies
• Tools for real-time monitoring

Day 1 Topics:

• What Are Pilot-Induced Oscillations?
• A Brief History of PIO (featuring a comprehensive collection of PIO Videos)
• Aircraft Dynamics and Augmentation
• Pilot Dynamics in Closed-Loop Control Triggers
• The Categories and Causes of PIO
• Rating the PIO
• PIO Flight Research Programs
• Designing Category I PIO Resistant Aircraft

Day 2 Topics:

• Designing Category I PIO Resistant Aircraft (continued): A Comparative Evaluation of Category I Criteria
• Designing Category II PIO Resistant Aircraft
• Detection and Prevention in Real-Time
• Testing for PIO
• PIO Case Studies (including X-15, F-14, V-22, F/A-18F, T-45, & B777)
• Summary and Conclusions

The course has been taught on site for the following organizations:

Boeing Phantom Works	Long Beach, CA
Naval Air Systems Command	NAS Patuxent River, MD
Boeing Integrated Defense Systems	Philadelphia, PA
US Air Force Flight Test Center	Edwards AFB, CA
Bell Helicopter Textron, Inc.	Arlington, TX
Sikorsky Aircraft Co..	Stratford, CT
NASA Dryden Flight Research Center	Edwards AFB, CA

Related Publications:

D. H. Klyde and C.-Y. Liang, Ph.D., “Flight Assessment of Pilot Behavior with Smart-Cue and Smart-Gain Concepts Active,” AIAA 2009-5606 presented at AIAA Atmospheric Flight Mechanics Conference, Chicago, IL, August 10, 2009.

D. H. Klyde and C.-Y. Liang, Ph.D., “Approach and Landing Flight Evaluation of Smart-Cue and Smart-Gain Concepts,” Journal of Guidance, Control, and Dynamics, vol. 32, no. 4, pp. 1057-1070, 2009.

D. G. Mitchell and D. H. Klyde, “Identifying a Pilot-Induced Oscillation Signature:  New Techniques Applied to Old Problems,” Journal of Guidance, Control, and Dynamics, vol. 31, no. 1, pp. 215-224, 2008.

D. H. Klyde and D. T. McRuer, “Smart-Cue and Smart-Gain Concepts Development to Alleviate Loss of Control,” Journal of Guidance, Control, and Dynamics, vol. 32, no. 5, pp. 1409-1417, 2009.

D. G. Mitchell and D. H. Klyde, “Testing for Pilot-Induced Oscillations,” AIAA 2005-5811 presented at AIAA Atmospheric Flight Mechanics Conference and Exhibit, San Francisco, CA, August 15-18, 2005.

D. H. Klyde and D. G. Mitchell, “A PIO Case Study - Lessons Learned through Analysis,” AIAA 2005-5813 presented at AIAA Atmospheric Flight Mechanics Conference and Exhibit, San Francisco, CA, August 15-18, 2005.

D. H. Klyde and D. G. Mitchell, “Recommended Practices for Exposing Pilot-Induced Oscillations or Tendencies in the Development Process,” AIAA 2004-6810 presented at USAF Developmental Test and Evaluation Summit, Woodland Hills, CA, November 16-18, 2004.

D. H. Klyde and D. G. Mitchell, “Investigating the Role of Rate Limiting in Pilot-Induced Oscillations,” Journal of Guidance, Control, and Dynamics, vol. 27, no. 5, pp. 804-816, 2004.

D. G. Mitchell, V. Sahasrabudhe, and D. H. Klyde, “Determining Bandwidth in the Presence of Nonlinearities,” AIAA 99-0639presented at AIAA 37th Aerospace Sciences Meeting and Exhibit, Reno, NV, January 11-14, 1999.

D. H. Klyde, D. G. Mitchell, and K. J. Latimer, “Development of the Probe-and Drogue Handling Qualities Demonstration Maneuver,” Journal of Guidance, Control, and Dynamics, vol. 22, no. 4, pp. 528-535, 1999.

D. H. Klyde and D. G. Mitchell, “Extraction of Pilot-Vehicle Characteristics In the Presence of Rate Limiting,” AIAA 99-1069 presented at AIAA 37th Aerospace Sciences Meeting and Exhibit, Reno, NV, January 11-14, 1999.
D. G. Mitchell and D. H. Klyde, “A Critical Examination of PIO Prediction Criteria,” AIAA-98-4335 presented at AIAA Atmospheric Flight Mechanics Conference and Exhibit, Boston, MA, August 10-12 1998.

D. H. Klyde, D. T. McRuer, and T. T. Myers, “Pilot-Induced Oscillation Analysis and Prediction with Actuator Rate Limiting,” Journal of Guidance, Control, and Dynamics, vol. 20, no. 1, pp. 81-89, 1996.

D. G. Mitchell, B. L. Aponso, and D. H. Klyde, “Feel Systems and Flying Qualities,” AIAA 95-3425 presented at AIAA Atmospheric Flight Mechanics Conference, Baltimore, MD, August 7-10, 1995.

D. G. Mitchell, R. H. Hoh, B. L. Aponso, and D. H. Klyde, “The Measurement and Prediction of Pilot-in-the-Loop Oscillations,” AIAA-1994-3670 presented at AIAA Guidance, Navigation and Control Conference, Scottsdale, AZ, August 1-3, 1994.

About the Speakers:

David H. Klyde is Vice President Engineering and Research Services for Systems Technology, Inc., in Hawthorne, CA.  Mr. Klyde’s more than 23 years of air vehicle experience includes dynamic analysis and system identification, flight control system design and analysis, human operator models, and handling qualities research for transport, fighter, drone, flying wing, rotorcraft and V/STOL, and hypersonic aircraft.

David G. Mitchell is President of Mitchell Aerospace Research, in Long Beach, CA. In his professional career of more than thirty years, Mr. Mitchell has been a contributor to the development of flying and handling qualities requirements for every type of air vehicle.