What system does the anti-servo tab help control?

The anti-servo tab is a crucial component in the control systems of an aircraft, specifically designed to enhance pitch stability. By providing a force that opposes the normal control surface deflection, the anti-servo tab increases the control surface's resistance to movements, thereby helping to stabilize the aircraft against pitch fluctuations.

As control surfaces like elevators are moved to adjust the aircraft's nose up or down, the anti-servo tab acts to dampen excessive movements that could lead to instability. It essentially creates a feedback mechanism that encourages more consistent and controlled pitch angles, which is essential for maintaining stable flight conditions, particularly during maneuvers or turbulent weather.

Engaging with other options, yaw stability primarily involves movement around the vertical axis and is managed by rudders rather than pitch control surfaces. Roll stability pertains to the aircraft's ability to maintain its orientation along the longitudinal axis and is addressed through ailerons and other lateral control mechanisms. Speed stability relates to maintaining a constant airspeed and is influenced by factors such as thrust and drag rather than directly controlled by the anti-servo tab. Thus, the association of the anti-servo tab with pitch stability is fundamentally correct, highlighting its role in ensuring smooth and controlled flight dynamics.