What is the primary function of an anti-servo tab?

The primary function of an anti-servo tab is to prevent a control surface, such as an elevator or a rudder, from moving to full deflection. This design feature is particularly important because it helps to increase the control surface's stability and predictability. By providing a counteracting force, the anti-servo tab enhances the pilot's ability to maintain controlled flight, especially at higher speeds where full deflection might lead to over-rotation or loss of control.

In practical terms, the anti-servo tab moves in the opposite direction of the control surface, increasing the control authority at lower deflections while preventing excessive movement that could lead to unwanted or abrupt changes in aircraft attitude. This is crucial for maintaining controllability during various phases of flight, especially during maneuvers that require a delicate balance of control inputs.

This function makes the anti-servo tab especially valuable in aircraft that might experience sensitivity or over-responsiveness in their controls. It serves as a physical reminder and a structural feature to ensure that control inputs are within safe operational limits, promoting smoother handling and reducing the likelihood of pilot-induced oscillations or other control issues.