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What’s the difference between SERVO VS ANTI-SERVO TABS?

Secondary flight controls that aren’t defined as major controls are referred to as secondary controls. Flaps, trimming devices, spoilers, slats, slots, and speed brakes are the auxiliary or secondary flight controls. On some planes, the secondary flight controls aren’t always available.

Servo tabs and anti-servo tabs are connected directly to the flight control system.

Servo Tab

Purpose: To reduce the control force required by the pilot to move the controls.

Location: At the primary flight control surface that moves directly based on the pilot’s control

Operation: If the pilot defected the servo tabs, the flight control surface will be also deflected. This is due to the force of the airflow on the servo tabs that helps the free movement of the primary flight control surface.

Movement: Servo tabs move in the opposite direction of the control surface.

A servo tab is a small component that attaches to the aircraft’s control surfaces. Negative feedback is not used by these devices to keep the control surface in place.

Servo tabs make it easier for pilots to manipulate the airplane’s control surfaces. Pilots can utilize them to produce resistance, causing the plane to move in a specific direction.

Anti-servo Tab

Purpose: Increase the control effectiveness and the hinge moment.

Location: At the primary flight control surface that moves directly based on the pilot’s control

Operation: It deploys in the same direction as the control surface, making the movement of the control surface more difficult and requiring more force applied to the controls by the pilot.

Movement: Anti-servo tabs move in the same direction of the control surface but farther.

Anti-servo tabs, also known as anti-balance tabs, are the polar opposite of servo tabs. It extends in the same direction as the control surface, making control surface movement more challenging and necessitating the pilot’s application of more effort to the controls.


Anti-servo tabs are typically employed on aircraft with light controls or that require more stability in that axis of movement. The anti-servo tab’s primary purpose is to make the controls feel heavier to the pilot, as well as to improve stability.

the difference between servo vs anti-servo tabs aircraft wing airfoil

Conclusion

What’s the difference between the servo tabs and the anti-servo tabs?

Servo tabs can be used as a stand-alone balance device that aims to reduce the force needed by the pilot to move the control surface.

While the anti-servo tabs can’t be used as a stand-alone device and it aims to counter the use of servo tabs by increasing the force needed by the pilot to move the control surface.