Hydraulics

Question 1

What is the maximum system pressure in A/B systems?

Answer 1

3500 psi

FCOM 13.10.2

Question 2

When the STANDBY HYDRAULIC LOW QUANTITY Light is armed?

Answer 2

Always armed.

FCOM 13.10.4

Question 3

What are the main components that are powered by system B?

Answer 3

Ailerons
Rudder
Elevator
Leading edge flaps + slats
Trailing edge flaps
Normal brakes
No. 2 thrust reverser
A/P B
Alternate nose wheel steering
Autoslats
Yaw Damper
(FCOM 13.20.3)

Question 4

What are the main components powered by System A?

Answer 4

Ailerons
Rudder
Elevator
Flight spoilers
Ground spoilers
Alternate brakes
No. 1 thrust reverser
A/P A
Normal nose wheel steering
Landing gear
Tail skid (900)
PTU
(FCOM 13.20.3)

Question 5

What is the minimum fuel for ground operation of electric motor-driven pump?

Answer 5

760 kg in the related main tank.

FCOM 13.20.4

Question 6

What is the Power Transfer Unit (PTU)?

Answer 6

The purpose of the PTU is to supply the additional volume of hydraulic fluid needed to operate the autoslats and leading edge flaps and slats at the normal rate when system B engine–driven hydraulic pump volume is lost. System A pressure -> system B fluid.
Conditions:
1. System B engine–driven pump hydraulic pressure drops below limits;
2. Airborne;
3. Flaps not up (SFP)/less than 15 but not up;
(FCOM 13.20.5)

Question 7

What is Landing Gear Transfer Unit?

Answer 7

The purpose of the landing gear transfer unit is to supply the volume of hydraulic fluid needed to raise the landing gear at the normal rate when system A engine–driven pump volume is lost. The system B engine–driven pump supplies the volume of hydraulic fluid needed to operate the landing gear transfer unit when all of the conditions exist:
1. Airborne;
2. No. 1 engine RPM drops below a limit value;
3. Landing gear lever is positioned UP;
4.Either main landing gear is not up and locked.
(FCOM 13.20.6)

Question 8

What are the components of the Standby Hydraulic System?

Answer 8

1. Thrust reversers;
2. Rudder;
3. Leading edge flaps and slats (extend only);
4. Standby yaw damper.
   (FCOM 13.20.6)

Question 9

What are the options to operate manually the Standby Hydraulic system?

Answer 9

1. Positioning the either FLT CONTROL switch to STBY RUD;
2. Positioning the ALTERNATE FLAPS master switch to ARM.
   (FCOM 13.20.6)

Question 10

What are the conditions for automatic operation of the Standby Hydraulic system?

Answer 10

1. Loss of system A/B;
2. Flaps extended;
3. Airborne, or wheel speed>60k;
4. FLT CONTROL switch A/B Hydraulic system ON.
   OR:
   The main PCU FFM trips.
   (FCOM 13.20.7)

Question 11

What will be the system B fluid level, in case of a leak in the standby system?

Answer 11

Approximately 72%.

FCOM 13.20.9