An Investigation of Side-Stick Controller/Stability and Control Augmentation System Requirements for Helicopter Terrain Flight under Reduced Visibility Conditions,

Abstract : A simulator experiment evaluated the effects of side-stick-controller characteristics and level of stability and control augmentation on handling qualities for several helicopter, low-altitude flight tasks conducted at night or in adverse weather. These reduced visibility tasks were simulated by providing the pilot with a visually coupled, helmet-mounted display of flight-control symbols superimposed upon terrain-board imagery. Forward-flight, low-speed, and precision-hover control modes were implemented, and a method for blending of control laws between each control mode was developed. Variations in the level of integration of primary control functions on a single side-stick controller were investigated. For most of the flight tasks investigated, separated controller configurations were preferred to a single, fully integrated sidestick device. Satisfactory handling qualities over all controller configurations were achieved only for a precision-hover task conducted with a high level of stability and control augmentation. Significant degradation in handling qualities occurred for most tasks flown with the helmet-mounted display relative to identical tasks flown under visual flight conditions.