SH Chapter 12 - Hydraulics

Question 1

1) What occurs when you press the RAT MAN ON pushbutton?

Answer 1

RAT manually extends.

Question 2

2) Does the PTU transfer hydraulic fluid?

Answer 2

No

Question 3

3) How many hydraulic pumps are in the GREEN system?

Answer 3

One plus PTU

Question 4

4) How many hydraulic pumps are in the BLUE system?

Answer 4

2

Electric and RAT pump.

Question 5

5) How many hydraulic pumps are in the YELLOW system?

Answer 5

3

Engine driven, electric and hand pump plus PTU

Question 6

6) When does the BLUE ELEC PUMP operate?

Answer 6

In flight and on the ground if one engine running and BLUE PUMP OVRD pb pressed on MX panel.

Question 7

7) What is normal system hydraulic pressure?

Answer 7

3000 psi +/-200 psi

Question 8

8) Does the RAT automatically deploy with the loss of BLUE hydraulic?

Answer 8

No. With the loss of AC BUS 1 and 2 and speed over 100 kts.

Question 9

9) What condition will cause the PTU to operate when the pushbutton is in AUTO?

Answer 9

Differential pressure between green and yellow is greater than 500 psi.

Question 10

10) When is the PTU inhibited?

Answer 10

• PTU pb is off
• During first engine start
• During cargo door operation and for 40 seconds after
• On ground when only one engine master switch on and NWS deactivated and/or parking brake on
• In flight, when a green or yellow low pressure condition is detected for more than 6 seconds (prevents the operative hydraulic system from overheating in the
  case of low fluid in the inoperative system)