Definition
The wheel-mounted friction devices on an aircraft's main landing gear that slow or stop wheel rotation, allowing the pilot to decelerate during landing rollout, control taxi speed, hold the aircraft stationary during runup, and assist with directional control on the ground. Most light aircraft use independent hydraulic disc brakes operated by toe pressure on the top of each rudder pedal, with each brake controlling its respective main wheel.
Plain English
The brakes on the main wheels that the pilot uses to slow down on the runway, control speed while taxiing, and hold the airplane still during engine checks.
Context Anchor
Pilots use and check brakes during preflight, taxi, landing rollout, engine checks, and parking.
Derivation
Brake comes from older English words connected with breaking or stopping motion. That helps the aviation meaning: aircraft brakes do not power the airplane; they restrain wheel movement so the airplane can be controlled on the ground.
Why Pilots Care
Proper brake use prevents runway excursions and allows precise control during ground handling.
Intuition Check
Do not confuse brakes with an in-air speed control. Brakes work on the wheels, so they mainly matter while taxiing, landing, stopping, or parking.
Example Sentence 1
After touchdown, the pilot lowered the nosewheel and applied gentle, even brake pressure to slow the aircraft before turning off the runway.
Example Sentence 2
Using differential brakes, the pilot turned the airplane onto the taxiway.