Hydraulics

Question 1

Hydraulic Demand Pump in AUTO

Answer 1

demand pump operates when:

• respective engine hydraulic pump is low
• respective FUEL CONTROL switch is CUTOFF
• pumps 1 and 4 operate with flaps are in transit or past position 1

Question 2

Amber Hydraulic Sys FAULT light

Answer 2

• low HYD sys pressure
• low HYD reservoir quantity
• high HYD fluid temp

Question 3

How many Hydraulic Systems

Answer 3

• 4 powered by respective engine (HYD 1, 2, 3, 4)

Question 4

What does each HYD consist of?

Answer 4

HYD 1:

• 1 x Engine Driven Pump (EDP)
• 1 x bleed air driven Demand Pump
• 1 x HYD Interface module (HYDIM) - processes temp and pressure inputs
• 1 x electric AUX pump (for ground handing) (PAX)

HYD 2:

• 1 x EDP
• 1 x electric driven Demand Pump
• 1 x HYDIM

HYD 3:

• 1 x EDP
• 1 x electric driven Demand Pump
• 1 x HYDIM

HYD 4:

• 1 x EDP
• 1 x bleed air driven Demand Pump
• 1 x HYDIM
• 1 x electric AUX pump (for ground handling)

Question 5

Which HYD systems control steering and brakes?

Answer 5

HYD Sys 1:

• nose wheel steering and body steering
• alternate brakes

HYD Sys 2:
- alternate brakes

HYD Sys 4:
- normal brakes

Question 6

Which HYD systems control flaps and landing gear?

Answer 6

HYD 1:

• Inboard trailing edge flaps
• Nose and Body Landing Gear

HYD 4

• Outboard trailing edge flaps
• Wing Landing Gear

Question 7

Which HYD systems control ailerons and elevators?

Answer 7

All systems provide redundant control

HYD 1: left outboard/inboard aileron and left outboard/inboard elevator
HYD 2: left outboard/right inboard aileron and left inboard elevator
HYD 3: right outboard/left inboard aileron and right inboard elevator
HYD 4: right outboard/inboard aileron and right outboard/inboard elevator

Question 8

RF displayed next to HYD QTY on status display

Answer 8

Displayed on the ground when reservoir requires REFILL

• inhibited in flight and replaced by LO

Question 9

DEMAND Pump Selector in AUX

Answer 9

• aux pump operates on the ground until respective engine pump pressurizes
• respective demand pump off

Question 10

Demand Pump Low PRESS Light

Answer 10

• demand pump selector OFF or AUX

- demand pump commanded to operate and output pressure is low

Question 11

Purpose of Demand Pumps and AUX pump

Answer 11

Demand pumps: supply normal system demand if associated engine or EDP fails

AUX pump: electric pump for ground handling operations

Question 12

What controls pump logic and processes HYD temp and pressure?

Answer 12

Dedicated hydraulic interface modules (HYDIM) on each system

Question 13

What happens in the hydraulic system when an engine fire switch is pulled

Answer 13

• respective hydraulic fluid shutoff valve closes
• EDP depressurizes
• respective demand pump operates

Question 14

Equipment on HYD Sys #1

Answer 14

• Center AP
• Left OB and IB Aileron
• Upper Rudder
• IB Trailing Edge Flaps
• Nose and Body Gear and Steering
• Alternate Brakes
• Left OB and IB Elevator

Question 15

Equipment on HYD SYS #2

Answer 15

• Right AP
• Left OB Aileron and Right IB Aileron
• Spoilers
• Lower Rudder
• Lower Yaw Damper
• Alternate Brakes
• Elevator Feel
• Stab Trim
• Left IB Aileron

Question 16

Equipment on HYD SYS #3

Answer 16

• Left AP
• Left IB Aileron and Right OB Aileron
• Spoilers
• Upper Yaw Damper
• Upper Rudder
• Elevator Feel
• Stab Trim
• Right IB Elevator

Question 17

Equipment on HYD SYS #4

Answer 17

• Right IB and OB Aileron
• Spoilers
• Lower Rudder
• OB Trailing Edge Flaps
• Wing Gear
• Normal Brakes
• Right IB and OB Elevator

Question 18

When do Demand Pumps #1 and #4 operate when in AUTO?

Answer 18

• respective EDP low pressure
• respective FUEL CONTROL switch CUTOFF
• on the ground with flaps past 1 (pumps shut off when flaps reach position)
• inflight with flaps past 1 (pumps continue to run)

Question 19

What happens if a yaw damper fault exists?

Answer 19

• hydraulic power is removed from the related yaw damper system
• related INOPERATIVE light illuminates

Question 20

What drives the Engine Driven Pump?

Answer 20

N2 Accessory Gear Box