Hydraulics

Question 1

At what pressure does the high pressure release valve open?
At what pressure does the low pressure relief valve open?

Answer 1

122 bar
7.5 bar (to avoid damage to the reservoir)

Question 2

Which hydraulic system has a tail rotor shutoff valve?

Answer 2

System 1

Question 3

Is use of the test hydraulic switch permitted in flight?

Answer 3

No

Question 4

What are the hydraulic pumps driven by?

Answer 4

The accessories drive of the main transmission.

Question 5

What is meant by constant pressure, variable delivery?

Answer 5

When turning at normal speed the pressure remains the same, only the volume changes according to demand.

Question 6

What does the valve block portion of the hydraulic system contain?

Answer 6

Check valve (preventing the fluid from returning to the pump if the pump fails)
Filter
Shutoff valve (for testing and for tail rotor shutoff in system 1)
Pressure transducer assembly (for displaying hydraulic pressure and generating a low pressure caution if pressure drops too low)

Question 7

What is the purpose of the bypass/shutoff valve in the main actuators?

Answer 7

To prevent hydrostatic lock

Question 8

Hydraulic system pressure limits
Minimum and maximum

Answer 8

69 bar to 150 bar (hight pressure relief valve max flow)

Question 9

Hydraulic system pressure limits
Lower caution range
Continuous operation
Upper caution range

Answer 9

69-90 bar
90-120 bar
120-122 high pressure relief valve starts to open

Question 10

What is the fluid capacity of each system and is there a temperature limit?

Answer 10

1.2 litres
no