Comparison and analysis of pilot-induced oscillation characteristics from flight test and ground-based simulation

Abstract

The usual metrics for characterizing Pilot-InducedOscillation (PIO) are the Cooper-Harper pilot opinion rating, PI0 ratings scales, pilot comments and task perfbrmance. In Reference [ 1 J, the pilot ratings in the ground simulation of an offset-landing task did not match flight ratings; however, they exhibited similar trends. Best configurations in flight were also best configurations in ground simulation; however, they were slightly better in flight than on the simulators. Worse configurations in flight were also worse configurations in the simulators; but they were not as bad in ground simulation as they were in flight. Mediocre configurations in flight were not always mediocre configurations in ground simulation. In general, the confidence in the ability to predict flight characteristics is not high enough to use as a basis for program decisions. One major factor in these differences may be the pilot adaptation to’ the different environments (motion and visual cues, feel system, risk, etc.). This paper examines the phase lag between pilot input and aircraft response, as well as the PI0 frequencies and magnitudes in ground-simulation and flight data. The power spectra content of pilot signatures are also evaluated to understand pilot behavior during PIO. This is done in hopes of achieving a better understanding of pilot adaptation to ground simulation which in turn may help to better structure the procedures for PI0 testing and thus improve our ability to predict flight results.