Stick pusher

A stick pusher is a device installed in some fixed-wing aircraft to prevent the aircraft from entering an aerodynamic stall. Some large fixed-wing aircraft display poor post-stall handling characteristics or are vulnerable to deep stall. To prevent such an aircraft approaching the stall the aircraft designer may install a hydraulic or electro-mechanical device that pushes forward on the elevator control system whenever the aircraft's angle of attack reaches the predetermined value, and then ceases to push when the angle of attack falls sufficiently.^[1] A system for this purpose is known as a stick pusher.

The safety requirements applicable to fixed-wing aircraft in the transport category, and also to many military aircraft, are relatively demanding in the area of pre-stall handling qualities and stall recovery. Some of these aircraft are unable to comply with these safety requirements relying solely on the natural aerodynamic qualities of the aircraft. In order to comply with regulatory requirements, aircraft designers may opt to install a system that will constantly monitor the critical parameters and will automatically activate to reduce the angle of attack when necessary to avoid a stall. The critical parameters include the angle of attack, airspeed, wing flap setting and load factor. Action by the pilot is not required to recognise the problem or react to it.