When is Low Pressure considered maintenance empty?

Low pressure is considered maintenance empty at 50 psi because this value represents the minimum pressure threshold at which the hydraulic system can still be checked for function and is regarded as an indication that components should be inspected or serviced. When the hydraulic pressure drops to this level, it's a sign that the hydraulic fluid is nearing depletion, triggering maintenance protocols to ensure the system remains safe and functional for operations.

Values such as 0 psi would indicate complete depletion of hydraulic fluid, while 100 psi and 150 psi signify that there is still adequate hydraulic fluid present, and thus not meeting the criteria for maintenance empty. Therefore, recognizing 50 psi as the critical point for maintenance action is essential for ensuring the operational readiness of the aircraft and safeguarding against hydraulic system failures.