Definition
Hinged or extendable panels on the wings (and sometimes the fuselage) that, when deployed, increase drag and, in the case of spoilers, also reduce lift by disturbing the airflow over the top of the wing. Speedbrakes are used primarily to slow the airplane or increase descent rate without changing pitch attitude. Spoilers serve the same drag function but are specifically designed to 'spoil' lift, which makes them effective for descent control in flight and for putting the airplane's weight firmly onto the wheels after touchdown.
Plain English
Panels that pop up out of the wings to slow the airplane down or help it descend faster. Spoilers also reduce how much lift the wing is producing, which is useful when landing or when you need to come down quickly without speeding up.
Context Anchor
Seen in stall recovery procedures, descent planning, landing configuration, and aircraft-specific operating manuals.
Derivation
Speedbrake' is straightforward — a brake for speed. 'Spoiler' comes from the verb 'to spoil,' meaning to ruin or disrupt. The panel ruins the smooth airflow over the wing, which is exactly how it kills lift.
Why Pilots Care
They allow the aircraft to descend rapidly or decelerate without increasing airspeed, which is critical during stall recovery and approach to landing.
Grounding Statement
Picture a flat panel popping up from the wing and interrupting the smooth air that normally helps the wing lift the airplane.
Intuition Check
A speedbrake is not a wheel brake, and a spoiler is not just something that slows the airplane. In this context, both are panels that change airflow over the airplane, often reducing lift as well as increasing drag.
Example Sentence 1
As part of the stall recovery, the pilot retracted the speedbrakes to restore full lift from the wings.
Example Sentence 2
After touchdown, raising the spoilers helps keep the airplane firmly on the runway by killing lift.