FCOM VOL2 Hydraulics

Question 0

When is the hydraulic pump low pressure light deactivated?

Answer 0

When the associated engine fire switch is pulled?

Question 1

What does the amber hydraulic “overheat” light indicate?

Answer 1

Indicates an overheat of either the pump or fluid.

Fluid is used to cool the electric driven hydraulic pump.

Question 2

What does switching the engine driven hydraulic pump switches on do?

Answer 2

It de-energises blocking valve in pump to allow pump pressure to enter system.

Question 3

What does switching the engine driven hydraulic switch off do?

Answer 3

Energises blocking valve to block pump out put.

Switch should be left in on position to prolong solenoid life.

Question 4

What is the quantity range of the hydraulic system?

Answer 4

0-106%

Question 5

When does the “RF” symbol illuminate?

What conditions must be met for it to illuminate?

Answer 5

76%

A/C must be on ground with both engines shutdown or after landing on taxi in with flaps retracted.

Question 6

Max hydraulic system pressure? And normal pressure?

Answer 6

Max 3500psi

Normal 3000psi. With all switches off reservoir pressure may indicate up to 100psi.

Question 7

What does switching the “FLT CONTROL” switch to “STBY RUD” do?

Answer 7

Activates the standby pump and open the the standby rudder shutoff valve to energise the standby rudder power control unit?

Question 8

What does switching the “FLT CONTROL” switch to off do?

Answer 8

It closes the flight control shutoff valve isolating ailerons, elevators and rudder from associated hydraulic system pressure.

Question 9

What light would you expect to illuminate during high hydraulic demand after the loss of an engine driven pump?

Answer 9

Intermittent illumination of low pressure light. Also flight control low pressure light and the master caution “FLT CONT & HYD” annunciation swill illuminate.

Question 10

System A hydraulic systems? (11).

Answer 10

Ailerons,
Elevator and elevator feel,
Rudder,
Flight spoilers 2 on each wing,
Ground spoilers,
Alternate brakes,
Thrust reverser no1,
Autopilot A,
Normal nose wheel steering,
Landing gear,
Power transfer unit(PTU).

Question 11

Hydraulic B systems?

Answer 11

Ailerons,
Elevator and elevator feel,
Rudder,
Flight spoilers 2 on each wing,
Leading edge flaps and slats,
Normal brakes ,
Thrust reverser No2,
Autopilot B 
Alternate nose wheel steering,
Auto slats,
Yaw damper,
Landing gear transfer unit,
Trailing edge flaps.

Question 12

How much more volume does the engine driven pump pump over electric pump?

Answer 12

6 times the volume.

Question 13

What is the minimum fuel in main tank reqd for operation of the electric hydraulic pump?

Answer 13

760kgs in respective main tank

Question 14

What will the fluid levels be with leak in the engine driven pump for hydraulic system A?

Answer 14

20%

Question 15

What will the fluid readout be if there is a leak in the electric pump in hydraulic system A?

Answer 15

0%

Question 16

What is indicated by a leak in hydraulic system B?

Answer 16

Fluid level indicated will read approx 0% but there is a standpipe in the reservoir which is sufficient to supply the power transfer unit.

Question 17

How does a leak in hydraulic system B affect the standby hydraulic system?

Answer 17

No affect.

Question 18

What is the purpose of the power transfer unit?

Answer 18

To apply additional volume of hydraulic fluid needed to operate the auto-slats and LE flaps and slats at the normal rate.

Question 19

How does the power transfer system work?

Answer 19

The PTU uses system A Hydraulic fluid to power a hydraulic motor driven pump which pressurises system B fluid.

Question 20

When does the PTU operate automatically?

Answer 20

System B fluid drops below limits,
Airborne,
Flaps not up.

Question 21

What is the purpose of the landing gear transfer unit?

Answer 21

Supply the volume of fluid needed to raise the landing gear at the normal rate when hydraulic system A engine driven pump is lost.

Question 22

When will hydraulic system B supply fluid to the landing gear transfer unit?

Answer 22

Airborne,
Engine no1 failure (results in engine driven pump stopping),
Landing gear lever in up position,
Either or both of the main landing gears not up and locked.

Question 23

What does the standby hydraulic system power?

Answer 23

Thrust reversers,
Rudder,
Leading edge flaps and slats (extend only),
Standby yaw damper.

Question 24

What does switching either flight control switch to STBY RUD do?
6 steps.

Answer 24

1. Activates the standby electric motor driven pump,
2. Shuts off the related hydraulic pressure to ailerons, elevator and rudder by closing the flight control shutoff valve.
3. Opens the standby rudder shut off valve.
4. Deactivates the flight control LOW PRESSURE light when the standby rudder shut off valve opens.
5. Allows the standby system to power rudder and thrust reversers.
6. Illuminates the STBY RUD ON light and master caution and flight control lights.

Question 25

When will automatic operation of the standby hydraulic system occur?

Answer 25

Auto operation is initiated when...
Loss of system A or B pressure and
Flaps are down and
Airborne or wheel spin above 60kts and 
FLT Control switches A and B on.

Or
The Main PCU force fight monitor trips.

Question 26

If there is a leak in the standby hydraulic system what will the fluid leak too? What flight deck indications are there?

Answer 26

Standby fluid will leak to zero.

Hydraulic system B should reduce and stabilise at 72%.