Hydraulics

Question 1

Demand pumps come on in AUTO?

Answer 1

• Related ENG Pump output PRESS low
• Related Fuel Control Switch in CUTOFF
• Pumps 1 & 4 also w/flaps in transit/out of UP in FLT

Question 2

Hydraulic system SYS FAULT light on panel mean?

Answer 2

• LO PRESS
• LO Reservoir
• HI TEMP

Question 3

If engine driven pumps are operating normally, demand pumps 1 and 4 also operate?

Answer 3

• In transit on ground.

- Flaps out of UP in flight.

Question 4

Hydraulic demand pump LOW PRESS light indicate?

Answer 4

• Selector OFF or AUX
• Output pressure LOW with PUMP ON
• Pump failure

Question 5

When is ENG driven HYD pump pressurized?

Answer 5

• ENG running

- ENG Pump Switch ON

Question 6

Which HYD demand pumps are air driven?

Answer 6

SYS 1 & 4 through respective L/R bleed air manifold. Air sources include Engine Bleed Air and APU Bleed Air.

Question 7

Purpose of HYD AUX pump?

Answer 7

Used for ground ops until engine pump pressurizes.

• Example: Wheel Braking for towing.

Question 8

Why are HYD reservoirs pressurized w/bleed air?

Answer 8

• Prevent pump cavitation

- Ensure positive flow during HI demand conditions

Question 9

How does pulling FIRE Switch affect HYD SYS?

Answer 9

• EDHP SOV closes
• EDHP Depressurizes
• Related demand pump operates

Question 10

Which HYD systems provide redundant power to primary flight controls?

Answer 10

SYS 1 and 4

Question 11

HYD systems power primary flight controls?

Answer 11

SYS 2 and 3

Question 12

HYD systems for upper/lower YD?

Answer 12

Upper - HYD SYS 3

Lower - HYD SYS 2

Question 13

HYD system for stab trim and elevator feel?

Answer 13

HYD SYS 2 and 3

Question 14

Which HYD systems power AP servos L, C, and R?

Answer 14

L = HYD SYS 3
C = HYD SYS 1
R = HYD SYS 2

Question 15

Which HYD systems power the spoilers?

Answer 15

HYD SYS 2,3, and 4

Question 16

Gear retraction HYD systems (numbered)?

Answer 16

1
4 | | 4
1

Question 17

Speedbrake/Spoiler HYD systems (numbered)?

Answer 17

3-2-2-3 4-4 | | 4-4 3-2-2-3

Question 18

Trailing Edge Flaps HYD systems (numbered)?

Answer 18

4-1 | | 1-4

Question 19

PRESS amber light on engine pump switch?

Answer 19

Low engine HYD pump pressure

Question 20

What happens when Demand Pump selector is placed in AUX position?

Answer 20

Pressurizes SYS 4 on the ground if GROUND HANDLING BUS is powered.

Question 21

Aileron HYD SYS (numbered)?

Answer 21

(1/2)(1/3) | | (4/2)(4/3)

Question 22

Nosewheel and Body Wheel Steer HYD SYS?

Answer 22

HYD SYS 1

Question 23

Wheel Brakes HYD SYS?

Answer 23

NORM - SYS 4
ALT - SYS 1
ALT - SYS 2

Question 24

Elevator HYD SYS (numbered)?

Answer 24

(1)(1/2) | | (3/4)(4)

Question 25

Upper Rudder HYD SYS (numbered)?

Answer 25

1
3
3

Question 26

Lower Rudder HYD SYS (numbered)?

Answer 26

2

4

Question 27

What 4 monitors are observed when HYD SYS 4 - AUX ON?

Answer 27

• SYS FAULT Light OFF
• PRESS Light ON
• BRAKE SOURCE Light OFF
• ACCUMULATOR PRESS in GREEN band

Question 28

BRAKE ACCUMULATOR HYD SYS?

Answer 28

HYD SYS 4

Question 29

When will AUX Pump #4 stop its operation with the switch in the AUX position?

Answer 29

When the #4 EDHP is pressurized.

• EICAS: HYD PRESS DEM 4 displayed