With one engine operating and START R.BK switch activated, the rotor brake may remain on for how many minutes?

With one engine operating and START R.BK switch activated, the rotor brake may remain on for how many minutes?

• A. 5 minutes
• B. 2 minutes
• C. 3 minutes
• D. 4 minutes

Answer: (A)

When you have one engine operating and you enable the START R.BK switch, the rotor brake is allowed to stay engaged for up to five minutes. This limit exists because the rotor brake dissipates heat through friction, and with only one engine running the rotor isn’t turning to provide cooling, so heat can build quickly. The five-minute duration provides a safe window to complete the start sequence or to hold the rotor while coordinating the second engine start without risking brake overheating. If you need to keep it on longer, you’d follow the proper cooling or procedure steps; otherwise, the brake should be released to prevent damage.

When you have one engine operating and you enable the START R.BK switch, the rotor brake is allowed to stay engaged for up to five minutes. This limit exists because the rotor brake dissipates heat through friction, and with only one engine running the rotor isn’t turning to provide cooling, so heat can build quickly. The five-minute duration provides a safe window to complete the start sequence or to hold the rotor while coordinating the second engine start without risking brake overheating. If you need to keep it on longer, you’d follow the proper cooling or procedure steps; otherwise, the brake should be released to prevent damage.