What are flaps considered in terms of flight controls?

Flaps are classified as secondary flight controls because their primary function is to enhance the aircraft's performance during specific phases of flight, particularly during takeoff and landing. While primary flight controls, such as ailerons, elevators, and rudders, are fundamental for basic maneuverability and stability of the aircraft, secondary flight controls like flaps serve an important role in modifying aerodynamic characteristics.

Flaps increase the lift generated by the wings at lower speeds, allowing the aircraft to take off and land safely within shorter distances. They can also enable a greater angle of attack without stalling. This distinct function is reflective of their classification as secondary flight controls, as they complement the primary controls but are not essential for the fundamental operation and stability of the aircraft in flight.

In contrast, emergency flight controls refer to systems designed to manage an aircraft in case of a failure in primary systems, and stabilizer aids typically refer to devices that enhance stability rather than directly assisting with lift or drag changes. Thereby, these categories do not align with the specific role flaps play in flight.