Definition
A device used to slow, stop, or hold a moving part by converting kinetic energy into heat through friction. On an aircraft, brakes are fitted to the main landing gear wheels and are operated by the pilot to control ground speed, stop the aircraft after landing, hold it stationary during run-up, and assist in steering through differential application.
Plain English
A part that slows or stops the aircraft's wheels by pressing friction surfaces together. The pilot uses it on the ground to slow down, stop, or hold the aircraft still.
Context Anchor
You encounter this term during taxi, landing rollout, parking, run-up checks, and maintenance discussions about the landing gear.
Derivation
From Middle Dutch 'braeke,' meaning a device for crushing or breaking. The original sense was a mechanism that applied resisting force — the same idea carried into wheel brakes, which apply force to resist motion.
Why Pilots Care
Proper brake use prevents runway overruns, enables directional control through differential braking, and is essential for safe ground handling on short or contaminated runways.
Analogy
Like the brakes on a car, but engineered to manage the higher speeds and weights of an airplane without overheating or failing.
Intuition Check
Do not assume brake always means the same thing as in a car. In normal aircraft use, brake usually means the wheel brakes used on the ground; an aircraft may also have other named devices that slow it in flight.
Example Sentence 1
After touchdown, the pilot lowered the nose wheel and applied the brakes smoothly to slow the aircraft to taxi speed.
Example Sentence 2
During the preflight walk-around the student checked the brake lines and pads for leaks or excessive wear.