Systems - Hydraulics

Question 1

Difference in A and B pumps?

Answer 1

A - engine driven
B - backups

Question 2

When do B pumps operate in auto?

Answer 2

WOW and flaps out of 0

Question 3

Inboard brakes?

Answer 3

Hyd 3

Question 4

Outboard brakes?

Answer 4

Hyd 2

Question 5

Nosewheel steering?

Answer 5

Hyd 3

Question 6

What occurs with the loss of Hyd 2 and 3?

Answer 6

Manual landing gear extension
Nose wheel will not extend

Question 7

What is special about Hyd 3B power?

Answer 7

Normally powered by AC BUS 1 but also hardwired to ADG to be powered when deployed.

Question 8

Which 2 Hyds are not controlled by hydraulic panel and why?

Answer 8

1A and 2A because engine driven

Question 9

During flight with switches in AUTO, what are the conditions required for Hyd 1B and 2B to operate?

Answer 9

Respective bus powered
Any generator online
Flaps out of 0

Question 10

What is normal operating pressure and reservoir for Hyd?

Answer 10

3000 psi +/-200
45-85%

Question 11

What is the brake accumulator?

Answer 11

Provides back up pressure for brakes at 750psi ~6 pumps

Question 12

Why does 3A only have ON/OFF and no AUTO?

Answer 12

Runs continuously

Question 13

Which hyd system powers nose wheel steering?

Answer 13

System 3

Question 14

How is hydraulic system 3 cooled?

Answer 14

Has no cooling capability

Question 15

Selection of the HYDRAULIC control panel switches to AUTO causes pumps 1B and 2B to operate when:

Answer 15

• Buses powered
• Any gen operating
• Flaps out of 0

Question 16

Which pump would receive power in an emergency situation, regardless of switch position (ex all AC power is lost from engines and APU causing ADG deployment)?

Answer 16

3B