Flight Evaluation of Flight-Path Control for the STQL Approach and Landing

Flight experiments have been conducted to assess requirements for flight-path control for glide-slope tracking and for control of the flare and landing, particularly as applied to powered-lift STOL aircraft. The research aircraft used to perform landing approaches on a 7. 5-deg glide slope to landings on a 30 X 518 m (100 X 1700 ft) STOL runway provided the capability for evaluating a wide range of flight-path control characteristics. The flight results identified flight-path overshoot, flight-path/airspeed coupling, and vertical velocity damping to be the dominant aircraft response characteristics that affect glide-slope tracking. The one prominent contribution to control of flare using pitch attitude was the short-term response. Specific design considerations for the effective thrust turning of the high-lift system, thrust response lags of the engines, and the aircraft loading and operating conditions are discussed.