Which control surface is primarily used to relieve excessive control forces?

The flaps are control surfaces that extend downward from the trailing edge of the wings and are primarily used to increase lift at lower speeds during takeoff and landing. One of the effects of deploying flaps is that they can change the aerodynamic characteristics of the wing, allowing the aircraft to maintain controlled flight at slower speeds without requiring excessive control forces. When flaps are deployed, they increase the wing's camber and surface area, leading to a lower stall speed and more stable flight characteristics.

This addition of lift distribution can help relieve some of the control forces experienced by the pilot, especially when maneuvering at slower airspeeds. The ability to operate with less force is particularly beneficial during critical phases of flight, such as when approaching for landing or during low-speed maneuvers.

In contrast, while the other control surfaces (rudder, elevators, and ailerons) have their roles in controlling yaw, pitch, and roll respectively, they are not specifically designed to alleviate excessive control forces in the same manner that flaps can do in low-speed flight operations.