ATA 29 - HYDRAULIC POWER

Hydraulic pressure can be restored by.

• Compressing the fluid in a reservoir.

• The use of a pressure/heat exchanger.

• Compressing the air charge in an accumulator.

What is the colour of the band on a hydraulic seal?

• White

• Green

• Yellow.

Accumulators as fitted to aircraft hydraulic systems.

• Are only ever used in an emergency.

• Store fluid under pressure.

• Provide additional fluid if leaks occur.

When flushing hydraulic systems.

• Flush with methylated spirit.

• Flush with any hydraulic oil.

• Flush with same hydraulic oil.

A check flow valve in a hydraulic system prevents.

• Overpressure.

• Reverse flow.

• Pump cavitation.

A constant delivery pump has its output varied with.

• Servo pressure.

• Gears.

• Regulators.

A hydraulic closed system is one where.

• Most of the major components of the system are included in a self contained unit.

• Pressure is maintained at the selector valves at all times.

• There is no pressure at the selector valves when no functions are required.

What constitutes a hydraulic power pack?

• Variable swashplate pump.

• Reservoir, pump, selector valve, filter.

• Hydraulic oil accumulator.

If an accumulator loses air pressure, there will be.

• Rapid fluctuations of instruments.

• Pump cavitation.

• Rapid depressurisation of system.

One reason for fitting an accumulator in a hydraulic system is to.

• Minimize the possibility of pump cavitation.

• Absorb pressure surges.

• Relieve excess pressure.