Hydraulic supply systems

Question 1

The engine pump ON OFF switches control how many valves?

Answer 1

Two, one valve isolates the hydraulic supply to the engine driven pump and the other isolates the output. These are the same SOVs that are controlled by the fire handle.

Question 2

Why does the hydraulic pump ON OFF switch control input and output valves instead of the pump?

Answer 2

Because the pump has a shaft that is connected to the engine and cannot be disengaged. While the engine is spinning the pump is spinning.

Question 3

Which engines supply hydraulic pressure to which systems?

Answer 3

1 and 2 supply pressure to the utility system
3 and 4 supply pressure to the booster system`

Question 4

What does the AUX hydraulic system power?

Answer 4

Ramp and door, emergency pressure to the brakes and emergency pressure for the nose gear emergency extension