Experimental investigation of pilot dynamics in a pilot-induced oscillation situation

Abstract

Results are presented for an experimental fixed and moving-base flight simulator investigation of a generalized aircraft longitudinal pilot induced oscillation (PIO) situation. Data are given relative to four handling-quality areas 1) pilot dynamic performance when tracking sinusoidal inputs following the occurrence of PIO, 2) the influence of motion cues on such performance, 3) the effects of varying stick force on pilot dynamic behavior in the PIO situation, and 4) the effect of varying the vehicle short-period transfer function numerator term 1/T02* Increases in this term to values above the normal level associated with the simulated airframe yielded experimental PIO's. The intentional increases were accomplished at a high input rate in an effort to preclude significant initial pilot gain adaptation. Approximately five times the increase in 1/T0 2 which produced the moving-base PIO was needed to produce instances of fixed-base PIO. With only external visual cues available during an oscillation, the pilot did not appear to operate in a synchronous (pure gain) manner. The availability of full-scale motion cues with visual cues causes the pilot to appear more nearly synchronous in the visual loop; however, the same data more consistently show the pilot operating with lag dvnamics on the load factor cues.