Hydraulics General

Question 1

Q.4.13 Before pushback, which hydraulic system
must be depressurized (both pumps OFF and LOW
PRESSURE lights illuminated)?

Answer 1

System A

Reference: AOM 3.13

Question 2

Q.4.14 The aircraft must not be towed forward unless
both engines are shut down and which hydraulic
system is depressurized?

Answer 2

System A

Reference: AOM 3.13

Question 3

Q.4.15 How can the standby hydraulic pump be
activated?

Answer 3

Manually: By moving either FLT CONTROL switch to
STBY RUD or ALTERNATE FLAPS master switch to
ARM.

Automatically: Inflight or on the ground with a loss of
system A or B, under specific conditions, or

Force Fight Monitor (FFM) activation.

Reference: FRM 13.2.3.1, 13.2.3.2

Question 4

Q.4.16 What is the significant difference in capability
between an engine-driven pump and an AC electric
motor-driven pump?

Answer 4

An engine-driven pump supplies six times the fluid
volume than the related electric motor-driven
hydraulic pump.

Reference: FRM 13.2.2

Question 5

Q.4.17 What does an illuminated OVERHEAT light on
the Electric Hydraulic Pump indicate?

Answer 5

The associated electric motor driven pump is
overheated, or the hydraulic fluid used to cool and
lubricate the corresponding electric motor driven
pump is overheated.

Reference: FRM 13.1.1, QRH 13.2

Question 6

Q.4.18 For which components does the standby
hydraulic system provide back up for Systems A and
or B?

Answer 6

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

Reference: FRM 13.2.3