Applicability of pitch and flight path bandwidth criteria to transport aircraft with flight-path-rate response system

Abstract

A piloted simulation experiment was conducted at the NASA Ames, Vertical Motion Simulator facility, in August 1999, to investigate the applicability of the Pitch Attitude and Flight Path Bandwidth criteria on a nonconventional response-type system hi large transport aircraft. Historically, these flying qualities criteria were derived using primarily classical response-type systems, such as those based on angle-of-atta ck or pitch rate. The study presented herein addresses the relevance of these criteria in cases where the aircraft is augmented to provide direct control of another state, namely flight path rate. Additionally, the effects of the Heads-Up Display (HUD) on the subject flying qualities criteria were investigated. A group of test pilots performed lateral offset approaches and landings without the HUD, with the HUD displaying actual flight path at the Inertia! Measurement Unit, and finally, with the HUD showing a commanded flight path symbol that was tuned to the dynamics of the configuration. The results suggest that the flying qualities Level 1 boundaries of the Flight Path Bandwidth criterion could be relaxed somewhat, particularly if the HUD displays flight path command that is tuned to the vehicle's augmented dynamics. However, with no HUD, and with the basic HUD showing actual flight path, the pilots' ratings validate the current criteria. The HUD itself was shown to provide a handling qualities improvement equivalent to about one Cooper-Harper Rating in configuration s that were considered by the pilots as deficient but not necessarily unacceptable. For those configurations that were deemed unacceptable, however, introduction of the HUD resulted in no appreciable benefit.