Which component is NOT a primary flight control?

The flaps are considered secondary flight controls, primarily used to enhance the aerodynamic performance of the aircraft during specific phases of flight, such as takeoff and landing. They function by increasing the lift and drag of the wings, allowing for lower speed operations and improved handling characteristics during critical phases.

In contrast, ailerons, elevators, and rudders are classified as primary flight controls because they directly manipulate the aircraft's attitude and direction during flight. Ailerons control roll, elevators control pitch, and the rudder controls yaw. Understanding this distinction between primary and secondary flight controls is critical for pilots as it informs their operational use of these control surfaces in different flight situations.