What is the function of a rotor brake in helicopter operations?

• A. To increase rotor speed
• B. To decrease rotor speed after engine shut down
• C. To stabilize the flight
• D. To align the rotor blades

Answer: (B)

The function of a rotor brake in helicopter operations is specifically designed to decrease rotor speed after the engine has been shut down. Once the engine is off, the rotor system can continue to spin for a while due to inertia. The rotor brake engages to bring the rotor blades to a stop safely and efficiently. This is crucial as it prevents the blades from spinning freely, which could pose risks during ground operations, maintenance, or when transitioning from flight to the ground. The rotor brake also makes it easier for ground crews to perform their tasks without needing to deal with moving rotor blades, enhancing safety around the helicopter.

The other options relate to functions that are not characteristic of a rotor brake. For instance, it does not increase rotor speed or stabilize flight; rather, those functions involve different systems and mechanisms within the helicopter's operation and maintenance. Additionally, aligning the rotor blades is not a function of the rotor brake, as blade alignment is typically addressed during pre-flight inspections or maintenance checks rather than through braking systems.