Final answer:
The correct option is C. assist the pilot in moving the control surfaces. Spring tabs or servo tabs assist the pilot in moving the control surfaces and reduce the forces required by the pilot for control inputs.
Step-by-step explanation:
The purpose of spring tabs or servo tabs is to assist the pilot in moving the control surfaces. Spring tabs or servo tabs are small auxiliary control surfaces that are attached to the main control surfaces such as ailerons, elevators, or rudders. They are designed to reduce the forces required by the pilot to move the control surfaces and to improve the handling characteristics of the aircraft.
By deflecting the spring or servo tab, the pilot can induce a larger deflection in the main control surface. This allows for easier control inputs, especially at high speeds or during high-G maneuvers. Additionally, the spring or servo tab can also be used to trim the control surface and maintain the desired flight attitude, reducing the pilot's workload.
For example, on an aircraft with spring-tab ailerons, when the pilot moves the control stick to roll the aircraft, the spring tabs deflect in the opposite direction, assisting in moving the ailerons and providing better control. Similarly, servo tabs on elevators or rudders help the pilot move these control surfaces more easily.