About Aircraft Hydraulic Accumulators

Aircraft hydraulic accumulators are components in hydraulic systems that allow a no compressible fluid, such as oil, to be stored under pressure. An accumulator has two compartments separated by a flexible or movable partition such as a diaphragm, bladder, or piston. One compartment contains compressed air or nitrogen, and the other is connected to the source of hydraulic pressure.

Aircraft strut servicing equipment

When the oil is pumped into the accumulator, portable charging units or CPUs are used. The partition moves over and increases the pressure of the air.

This air pushing against the partition holds pressure on the oil. Hydraulic accumulators in an aircraft hydraulic system act as shock absorbers and provide a source of additional hydraulic power when heavy demands are placed on the system. The maintenance equipment is known generally as aircraft strut servicing equipment.

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Accumulator air preload refers to the charge of compressed air or nitrogen in one side of an accumulator.

The air preload is normally about one-third of the system hydraulic pressure and there is a good market for low-pressure strut charging kits.

When fluid is pumped into the oil side of the accumulator, the air is further compressed, and the air pressure and the fluid pressure become the same.

If the air preload pressure is too low, there will be almost no time between the regulator reaching its kick-in and kick-out pressures, and the system will cycle far more frequently than it should.

Hydraulic systems need to generally to be maintained, serviced, and adjusted in accordance with manufacturers' maintenance manuals and permanent component maintenance manuals. Hydraulic lines and fittings should be carefully inspected at regular intervals to ensure airworthiness.

Any evidence of fluid loss or leaks, loose anchorages, scratches, kinks, or other damage should be scrupulously managed, replaced or repaired. The role of the military or civil ground support equipment custom designer should not be underestimated.