Influence of roll command augmentation systems on flying qualities of fighter aircraft

Roll command augmentation systems (CAS), in which commanded roll rate is directly proportional to stick input, provide high roll authority and precise control over the entire flight regime. However, operational experience with high-gain CAS has revealed problems with their use. Oversensitivity to small control inputs, "roll ratcheting," and pilot-induced oscillation (PIO) are commonly encountered in the early stages of development. Recent flight test and operational experiences with high-authority CAS of fighter aircraft are reviewed. Possible sources of the problems encountered are suggested, and guidelines are proposed for improving the flying qualities of aircraft equipped with roll CAS. y Fas L'?