What are secondary flight controls?
Wing flaps, leading edge devices, spoilers, and trim systems constitute the secondary control system and improve the performance characteristics of the airplane or relieve the pilot of excessive control forces. Flaps are considered secondary flight controls. Unlike primary flight controls (such as the elevator, rudder, and ailerons), which directly control the plane’s movement, secondary flight controls like flaps help modify certain flight characteristics.Wing flaps, leading edge devices, spoilers, and trim systems constitute the secondary control system and improve the performance characteristics of the airplane or relieve the pilot of excessive control forces.