Elementary Hydraulic System

Question 1

What does this system do?

Answer 1

Drives an actuator which could be used to raise the landing gear, lower flap or operate a control surface

A selector valve diverts hydraulic pressure to either side of the actuator piston to cause it to move up or down

Question 2

Reservoir

Answer 2

Stores excess hydraulic fluid

Allows for thermal expansion of the fluid

Accommodates fluid coming back from the low pressure side of the actuator

The excess fluid helps to compensate for any system leaks

Question 3

NRV

Answer 3

Non-return valve prevents reverse flow

Question 4

Pump

Answer 4

Pressurises the fluid flow in the circuit

Question 5

Accumulator

Answer 5

Stores hydraulic fluid under pressure

Provides an emergency supply of pressure in the event of pump failure

Provides a head of fluid to the pump and helps to even out any pressure pulses caused by the pump

Question 6

Selector valve

Answer 6

Directs pressure to the appropriate side of the actuator

Question 7

Actuator

Answer 7

Houses a piston which is physically attached to the component it is designed to move

Question 8

Filter

Answer 8

Prevents foreign matter from being passed into the system

Question 9

PRV

Answer 9

Pressure relief valve dumps excessive system pressure back to the reservoir to prevent excessive pressure from damaging the system