Hydraulic System

Question 1

What does the The hydraulic power generation system consist of?

Answer 1

A hydraulic power pack
Reservoir
Main hydraulic accumulator
Brake accumulator
Emergency/parking brake accumulator

Question 2

What does the The hydraulic power generation system feed?

Answer 2

Landing gear system
Ground spoiler/speed brake system
Main brake system
Emergency/parking brake system

Question 3

What is a Hydraulic Accumulator?

Answer 3

Hydraulic accumulators store hydraulic fluid under pressure to supplement pump flow and reduce pump capacity requirements, maintain pressure and minimize pressure fluctuations in closed systems absorb shocks, and provide auxiliary hydraulic power in an emergency

Question 4

How is the Hydraulic System controlled?

Answer 4

DC power, supplied by DC Bus 2, provides hydraulic system control.

Question 5

What is the nominal pressure of the Hydraulic System?

Answer 5

3000 psi

Question 6

With AUTO selected on the Hydraulic System Panel, what system pressure range is
maintained by the hydraulic pump?

Answer 6

2400 – 3000 ± 50 PSI

Question 7

On the MFD System Status Synoptic page, what colour does the readout and pointer
become when the hydraulic pressure drops below 1500psi?

Answer 7

Yellow

Question 8

At what pressure does the Emergency Brake Accumulator Pressure turn yellow on the
synoptic page?

Answer 8

1800psi

Question 9

Where are the hydraulic power pack and reservoir located?

Answer 9

Behind the larger of the 2 forward hatches on the right-hand side of the a/c

Question 10

What is the PSI for the Brake and Emergency/Park Brake Accumulator?

Answer 10

Both accumulators are charged to 3000± 50 psi from the main system.

Question 11

The electric cooling fan operates when?

Answer 11

Weight On Wheels (WOW) is made
Nose gear down and locked
1 generator online

Question 12

What is the effect if the hydraulic pump is selected to ON?

Answer 12

The pump runs continuously, plus, the electric motor thermal cut-out and hydraulic oil
over temp protections are lost

Question 13

When will the Electric Motor be automatically be shut down?

Answer 13

The hydraulic return fluid switch senses temperature above 120 °C and will reset at 110 °C
The electric motor thermal temperature differential is reached and will reset once the temperature has reached the initial shutoff temp

Question 14

What does HYD HI TEMP mean?

Answer 14

Hydraulic temperature high

Question 15

What does HYD LO PRES mean and when does it show?

Answer 15

Hydraulic Pressure low at 1500 PSI.