Boundary-Escape Tracking: A New Conception of Hazardous PIO
Abstract
Pilot-induced oscillations (PIOs) have vexed many designers, scared many more flyers, and killed more than a few pilots and aircraft. In spite of decades of research and hundreds of lessons learned, hazardous PIOs remain a constant threat during most envelope expansion efforts. PIO prediction has assumed that all PIOs are essentially the same thing; a pilot maintaining a condition couples with the aircraft in a way that drives an oscillation. If the pilot's gains are high enough, the entire system is unstable and in severe jeopardy. The purpose of this paper is to challenge this assumption by describing how a previously unrecognized task, boundary tracking,' can explain some PIOs-especially the most hazardous sort. This new conception may lead to new methods of predicting, preventing, and recognizing the PIOs that present the greatest hazard to flight test and operational aircrew. Boundary tracking was conceived in an attempt to explain hazardous PIOs, but it may have predictive abilities in many areas of handling qualities design and testing. From minor PIOs such as pitch bobbles to the stop-to-stop PIOs that kill pilots and airplanes, pilots' attempts to avoid a condition may explain many events that pilots' attempts to maintain a condition cannot.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2004
- Accession Number
- ADA427054
Entities
People
- William G Gray
Organizations
- Air Force Test Center