What is the minimum pressure for the left and right APU start accumulators?

The correct value for the minimum pressure for the left and right APU start accumulators is 2,800 PSI. This pressure is critical for ensuring that the hydraulic system has sufficient force to engage the APU starter, which is necessary for reliable engine start operations. The integrity of the hydraulic pressure affects the efficiency and effectiveness of the starting process, as it directly influences the ability of the system to provide the necessary torque to start the APU.

In aviation practice, maintaining the correct pressure in the APU start accumulators is essential for operational safety and efficiency. A pressure level below the specified minimum could lead to insufficient engagement of the starter, resulting in potential start failures and could cause delays or additional maintenance requirements. Therefore, ensuring that the accumulators are charged to at least 2,800 PSI prior to starting the APU is a standard operational procedure that all ground crew and maintenance personnel must adhere to when preparing the aircraft for flight.