Hydraulics

Question 1

Can the auxiliary hydraulic pump be used to supply pressure if the right Fire Handle has been pulled?

Answer 1

Yes, it has a separate feed line from the right hydraulic reservoir.

Question 2

Where is the auxiliary hydraulic pump located?

Answer 2

In the right wheel well.

Question 3

To what setting do the engine driven pumps default to after a failure?

Answer 3

They electrically fail to the high 3000 psi output.

Question 4

What drives the engine driven fuel pumps?

Answer 4

N2 rotation.

Question 5

List the items powered by the left hydraulic system.

Answer 5

Left engine thrust reverse
Inboard spoilers
Elevator boost

Question 6

List the items powered by the right hydraulic system.

Answer 6

Gear
Right thrust reverse
Rudder
Outboard spoilers
Stairs

Question 7

How can hydraulic fluid supply to the engine driven hydraulic pump be stopped?

Answer 7

By pulling the corresponding engine fire handle.

Question 8

During normal flight what output do the hydraulic pumps operate at?

Answer 8

Engine driven pumps are operated at 1500 psi, and the alternate hydraulic pump is typically off.

Question 9

Where is each engine driven hydraulic pump located?

Answer 9

On each engine’s accessory gearbox.

Question 10

Where is the alternate gear pump located?

Answer 10

In the right wheel well.

Question 11

What must the alternate gear pump have in order to operate?

Answer 11

Hydraulic fluid on one side of the system and hydraulic pressure on the other.

Question 12

When will the hydraulic system priority valve open and close?

Answer 12

It will open at 1850 psi and close at 1500 psi.

Question 13

What is the point of the hydraulic priority valve?

Answer 13

To give the flight controls priority over other systems with pressure available.

Question 14

When the left hydraulic system drops below ________ psi what systems will not be available?

Answer 14

2000 psi

Wing flap outboard cylinders
Left nose wheel steering

Question 15

When the right hydraulic system drops below ________ psi what systems will not be available?

Answer 15

2000 psi

Wing flap inboard cylinders
Landing gear
Right nose wheel steering

Question 16

What is he purpose of the hydraulic relief valve?

Answer 16

To provide blowback relief when the spoiler surfaces are exposed to excessive air loads. (B2 8-192)

Question 17

When will the hydraulic pressure low light come on?

Answer 17

Approximately 1000 psi.

Question 18

What position should the depressurization valve be in before flight?

Answer 18

On which indicates pressure is available to the entire system. (System bypass is used for mechanical operations)

Question 19

Which bus powers the auxiliary hydraulic pump?

Answer 19

The right generator bus.

Question 20

What systems are backed up by an accumulator? How many accumulators are there for each of these systems?

Answer 20

Brakes (2)
Elevator boost (1)
Aft stairs (if installed 1)
Rudder (0)
Reverse (2)

Question 21

What systems receive pressure from both the left and right hydraulic systems?

Answer 21

Flaps and Slats
Nose wheel steering
Brakes
Ground spoilers

Question 22

What hydraulic gauges are powered by their respective L/R AC power?

Answer 22

Hydraulic pressure gauge
Hydraulic quantity gauge
Brake pressure gauge

Question 23

What is the power source for the aux hydraulic pump, and why?

Answer 23

Left AC power, this is in case of an damage on the right side of the aircraft for whatever reason.