Which type of tab moves in the opposite direction to the flight control's trailing edge?

The type of tab that moves in the opposite direction to the flight control's trailing edge is a balance tab. Balance tabs are attached to flight control surfaces, such as ailerons or elevators, and their movement helps to counteract the aerodynamic forces acting on the control surface. When the pilot moves the control stick or yoke, the control surface deflects, and the balance tab moves in the opposite direction. This motion provides a force that assists the pilot, making it easier to control the aircraft without requiring excessive effort to move the control surfaces.

This design is particularly beneficial during flight because it helps to reduce the control forces needed, especially at higher speeds where aerodynamic loads increase. The balance tab operates in conjunction with the primary control surface, enhancing the overall effectiveness and responsiveness of the aircraft's controls.