Definition
A small auxiliary control surface attached to the trailing edge of a primary flight control (such as an aileron, elevator, or rudder) that is mechanically linked to move in the opposite direction to the main control. This opposing movement creates an aerodynamic force that helps move the primary surface, reducing the physical effort the pilot must apply to the controls.
Plain English
A small flap on the back edge of a flight control that automatically moves the opposite way when the pilot moves the control, helping push the main surface and making it easier to fly the aircraft.
Context Anchor
Seen in aircraft flight control system descriptions, maintenance inspections, and discussions of how control forces are reduced.
Derivation
The word 'balance' here means to offset or counter a force, not to make something equal. The tab 'balances out' part of the aerodynamic load on the main control surface, so the pilot doesn't have to.
Why Pilots Care
Reduces pilot workload and prevents fatigue on long flights by lowering the physical force needed to hold or move the controls.
Analogy
It works like power steering in a car, using opposing force from the air to make the heavy control surface easier to move.
Intuition Check
A balance tab is not used to balance the airplane’s weight. It helps balance the air forces acting on a movable control surface.
Example Sentence 1
During the inspection, the technician confirmed the balance tab on the elevator moved opposite to the elevator itself, as designed.
Example Sentence 2
The pilot noticed lighter control forces after the balance tab was properly adjusted during the last inspection.