Definition
Small movable surfaces on the trailing edge of a stabilator that deflect in the same direction as the stabilator itself. They increase the force the pilot must apply to move the control, preventing the stabilator from being overly sensitive and from being deflected too far by light pilot input.
Plain English
A small flap on the back edge of a stabilator that pushes against the pilot's input, making the controls feel firmer and harder to over-move. Without it, the stabilator would feel twitchy and easy to over-control.
Context Anchor
Seen on airplanes with a stabilator, especially during preflight checks and when studying pitch control in the tail section of the airplane.
Derivation
Anti' means against, and 'servo' comes from the Latin 'servus' meaning servant or helper. A regular servo tab helps the pilot by reducing control force. An antiservo tab does the opposite — it works against the pilot's input to add resistance, so the controls don't feel too light.
Why Pilots Care
Provides stability and realistic control feel, reducing the risk of over-controlling the pitch axis on aircraft with all-moving tails.
Intuition Check
Do not assume the tab is there to make the control easier to move. An antiservo tab is mainly there to add feel and resistance so the stabilator is not too sensitive.
Example Sentence 1
During the preflight, the pilot checked that the antiservo tab on the stabilator moved freely and in the correct direction.
Example Sentence 2
During preflight the mechanic checked that the antiservo tabs moved in the same direction as the stabilator to confirm proper operation.