At what PSI is the rotor brake considered inoperative?

The correct PSI at which the rotor brake is considered inoperative is 450 PSI. This is an important operational benchmark for maintaining the safety and functionality of the rotor systems on helicopters. When the rotor brake pressure drops to this level, it indicates that the system may not provide sufficient stopping power for the rotor blades, thereby jeopardizing ground operations and possibly leading to dangerous situations during maintenance or pre-flight checks.

Maintaining the correct pressure in the rotor brake system is crucial for ensuring that the brake engages effectively when needed. When pressure readings fall below this threshold, it signals that the rotor brake may not operate as intended, necessitating further inspection or maintenance before the aircraft can be deemed safe for operation. This threshold is established to uphold safety standards and prevent mishaps related to rotor control during ground operations.