What is the most probable cause if an aircraft's constant-pressure hydraulic system cycles more frequently than usual with no fluid leakage detected?

If an aircraft's constant-pressure hydraulic system is cycling more frequently without any detected fluid leakage, it is likely due to low accumulator air preload. The accumulator in a hydraulic system acts as a reservoir that stores hydraulic fluid under pressure. The air preload in the accumulator helps maintain this pressure and provides a cushion for the hydraulic fluid.

When the air preload is low, the accumulator cannot store enough hydraulic energy. This deficiency can result in the pump cycling on and off more often to maintain system pressure, as it compensates for the loss of pressure caused by inadequate air preload. Consequently, the hydraulic pump has to work harder and more frequently to ensure that the hydraulic system operates effectively and maintains the necessary pressure.

In this situation, the other options would not explain the increased cycling effectively. For instance, high accumulator air preload would typically result in stable pressure and less frequent cycling of the pump. Clogged hydraulic lines might cause issues such as pressure drops or restricted flow, but they would usually lead to fluid leakage or other demonstrable pressure inconsistencies detectable during maintenance checks. Faulty hydraulic fluid could affect system performance, but it would more likely produce symptoms such as overheating or unresponsive hydraulic actuators rather than increased cycling frequency without any visible leakage. Thus, recognizing low accumulator air