What type of spoiler is extended only after the aircraft is on the ground?

The ground spoiler is specifically designed to be deployed only after the aircraft has landed. Its primary function is to increase drag and reduce lift, which helps in bringing the aircraft to a stop more efficiently. When the spoilers are extended on the ground, they disrupt the airflow over the wings, thereby enhancing the braking force and contributing to safer landings by preventing the aircraft from becoming airborne again during the landing rollout.

Flight spoilers, on the other hand, are used during flight to reduce lift and increase drag, assisting in descent and control of the aircraft. Speed brakes are similar to flight spoilers but are mainly intended for enhancing drag during flight rather than affecting lift during landing. Control tabs are mechanical devices typically used on control surfaces to enhance aircraft handling, rather than being used for deceleration or lift reduction. Thus, the ground spoiler stands out as the only option tailored for ground operations only.