Definition
A mechanical brake fitted to a helicopter's main rotor drive system that slows and stops rotor rotation after engine shutdown, and holds the rotor stationary while the aircraft is parked.
Plain English
A brake that stops the helicopter's spinning rotor blades after the engine is switched off, and keeps them from turning while the aircraft sits on the ground.
Context Anchor
You may encounter this term in helicopter shutdown procedures, ground handling instructions, and aircraft-specific checklists.
Derivation
Rotor comes from the Latin word rota, meaning “wheel.” Brake refers to a device that slows or stops movement. Together, rotor brake means a device that slows the rotating rotor system.
Why Pilots Care
Stops the blades quickly to prevent strikes, injury to people nearby, or damage to the aircraft on the ramp.
Analogy
It is somewhat like using the brake on a bicycle wheel, except it acts on the helicopter’s rotor system and must be used with much stricter timing and care.
Intuition Check
Do not think of a rotor brake as something that instantly stops the blades. It is a controlled brake for ground use, and the rotor may still take time to slow down.
Example Sentence 1
After completing the shutdown checklist, the pilot engaged the rotor brake to bring the main rotor to a stop.
Example Sentence 2
The rotor brake must be released before engine start so the blades can turn freely.