Servo tab

[2] Servo tabs are not true servomechanisms, as they do not employ negative feedback to keep the control surfaces in a desired position; they only provide a mechanical advantage to the pilot.

It deflects airflow, generating force on the whole control surface in the desired direction.

[3][4]: 612 In some large aircraft, the servo tab is the only control that is connected to the pilot's stick or wheel, as in the Bristol Britannia and its Canadian derivatives.

[3] With the "geared spring tab" variant, a pilot is able "to maneuver a vehicle weighing as much as 300,000 pounds flying at an airspeed of 300 miles per hour or more".

The Beechcraft RC-12 Guardrail uses a rudder trim tab which incorporates anti-servo action,[9] and the Beechcraft U-21 uses elevator and aileron trim tabs which incorporate anti-servo action.