Abstract: A method and apparatus for managing the trim of an airplane stabilizer whose elevator is controlled by a highly augmented elevator control law is disclosed. The augmented portion of the elevator command ##EQU1## is evaluated(13) to determine if it is above or below a variable threshold whose magnitude is dependent on airspeed. Portions above or below the threshold are integrated (15) to determine if the augmented portion of the elevator command is rapidly or slowly diverging. A stabilizer trim command is rapidly produced if the augmented portion of the elevator command is rapidly diverging and produced more slowly if the augmented portion is slowly diverging. The stabilizer trim command causes the production of a trim up or trim down command (25/27) depending upon whether the stabilizer needs to be moved up or down.

Abstract: A full authority engine-out control augmentation subsystem for use in a flight control system to assist a pilot and/or lateral-directional control subsystem in compensating for the yawing moment produced by the differential engine thrust that occurs when the power produced by an engine located on one side of a multi-engine aircraft is lost (or reduced) with respect to the other engines is disclosed. The engine-out control augmentation subsystem produces a compensating rudder command (27) based on straight-gain (21), lag filter (15) and washout filters (23 and (25) modifications of a differential engine thrust signal (11). The engine-out control augmentation subsystem will function with both conventional mechanical and electronic (fly-by-wire) flight control systems.