During rotor brake shutdown, what hydraulic pressure is applied?

During rotor brake shutdown, what hydraulic pressure is applied?

• A. 100-140 psi
• B. 150-180 psi
• C. 200-240 psi
• D. 50-90 psi

Answer: (B)

Rotor brakes are held in place by a controlled hydraulic pressure to keep the rotor from turning when the aircraft is shut down. The hold pressure used during rotor brake shutdown is in the range of about 150 to 180 psi. This level provides enough clamping force to prevent windmilling or movement while not being so high that it unnecessarily heats the brakes or wastes hydraulic power once the pumps are off. Pressures lower than this could fail to hold the rotor securely in gusting winds, while pressures higher than this would overwork the brakes and add unnecessary wear. So 150–180 psi is the designed hold pressure for shutdown.

Rotor brakes are held in place by a controlled hydraulic pressure to keep the rotor from turning when the aircraft is shut down. The hold pressure used during rotor brake shutdown is in the range of about 150 to 180 psi. This level provides enough clamping force to prevent windmilling or movement while not being so high that it unnecessarily heats the brakes or wastes hydraulic power once the pumps are off. Pressures lower than this could fail to hold the rotor securely in gusting winds, while pressures higher than this would overwork the brakes and add unnecessary wear. So 150–180 psi is the designed hold pressure for shutdown.