Hydraulic system

Question 1

What is the range of Hydraulic system quantity in percentage? (Displayed on the CDS)

Answer 1

0% – 106%

Question 2

When will “RF” appear next to the system quantity?

Answer 2

When quantity below 76%
- Will only appear when aircraft is on the ground with both engines shutdown or after landing with flaps up during taxi in.

Question 3

On the FLIGHT CONTROL switches, what does
A - STBY RUD do?
B - OFF do?
C - ON do?

Answer 3

STBY RUD - Activates standby pump and opens standby rudder shutoff valve to pressurise standby rudder power control unit.

OFF - Closes Flight control shutoff valve isolating ailerons, elevators and rudder from associated hydraulic system pressure

ON (Guarded position) - Normal operating position.

Question 4

Why does the STANDBY HYDRAULIC LOW PRESSURE LIGHT illuminate and what are is the caveat?

Answer 4

indicates that the output pressure of the standby pump is low however it is armed only when standby pump operation has been selected or the automatic standby function is activated.

Question 5

What is a good way of thinking of what is powered by Hydraulic system A and what is powered by system B?

Answer 5

A is the “Ground system” and B is the “Air system”
Caveats:
- Normal Brakes are powered by system B
- Alternate brakes are powered by system A

Question 6

How much more does fluid volume does an engine-driven hydraulic pump supply compared to the related electric motor-driven hydraulic pump?

Answer 6

6 times!

Question 7

What pump does ELEC2 power?

Answer 7

System A electric motor-driven pump
The electric pump switches power the opposite side’s electric pump.

Question 8

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

Answer 8

760Kgs in the related main fuel tank.

Question 9

If a leak develops in either pump, line or component of system B is full system pressure lost?

Answer 9

Yes - It has a Standpipe which supplies fluid to the PTU - A leak in the System B does not affect the operation of the standby hydraulic system.

Question 10

If a leak develops in the engine driven pump or it’s related lines in system A what happens?

Answer 10

A standpipe in the reservoir will keep around 20% of the fluid for the electric motor-driven pump.

Question 11

When does the landing gear transfer unit operate?

Answer 11

When all of these are met?
- No. 1 Engine RPM drops below limits
- Landing gear lever is up
- Either main landing gear is not up and locked.

Question 12

Standby hydraulic system powers what systems?

Answer 12

• Standby rudder
• Thrust reversers
• Standby Yaw damper
• Leading edge flaps and slats (Extend only)

Question 13

What conditions need to be present to automatically initiate the Automatic standby rudder?

Answer 13

Loss of A or B and:
- Flaps extended and airborne or wheel speed >60kts and FLT CONTROL switch to on (Normal position)

Question 14

If the Standby hydraulic system leaks and decreases to zero, does this affect the system B quantity?

Answer 14

Yes - Causes it to drop to around 70%

Question 15

Minimum fuel for ground operation of electric motor driven pumps is ?kgs in the related main tank

Answer 15

760kgs

Question 16

Automatic operation of the Standby hydraulic system occurs with flaps extended/retracted (Pick one) and airborne or with a wheel speed greater than ??

Answer 16

Extended and 60kts

*FLT CONTROL for A or B should be on.