757 Hydraulic System

Question 1

What is indicated by the hydraulic control panel “SYS PESS” light?

Answer 1

Low pressure in the associated hydraulic system

Question 2

What is indicated by the “RSVR” light on the hydraulic control panel?

Answer 2

Low fluid quantity (less than 50%) or low pneumatic head pressure in the reservoir.

Question 3

What does the amber “PRESS” light mean on an associated hydraulic pump?

Answer 3

Pump output pressure is low

Question 4

What will happen if both center electric pumps are on and there is only one electrical source?

Answer 4

The right electric hydraulic pump will load shed

Question 5

What does the “OVHT” light on the hydraulic control panel indicate?

Answer 5

An overheat in the associated pump case drain cooling

Question 6

What happens when you turn off the engine driven hydraulic pump?

Answer 6

The associated engine driven pump is depressurized. This prevents pump output. Fluid continues to circulate through the pump for cooling and lubrication.

Question 7

How many independent hydraulic systems?

Answer 7

Three

Question 8

What systems are controlled by the left hydraulic system?

Answer 8

Flaps and slats
Steer and gear
Alternate brakes
Flight controls
Left thrust reverser
Main cargo door
Reserve fluid for PTU

Question 9

What systems are controlled by the center hydraulic system?

Answer 9

Flight controls

Reserve fluid for RAT

Question 10

What systems are controlled by the right hydraulic system?

Answer 10

Flight controls
Right thrust reverser
Normal brakes
Reserve fluid for reserve brakes

Question 11

What does “SYS PRESS” light on the hydraulic control panel indicate?

Answer 11

Low pressure in the associated system

Question 12

What does the “RSVR” light on the hydraulic control panel indicate?

Answer 12

Low quantity or head pressure

Question 13

What does the “OVHT” light on the hydraulic control panel indicate?

Answer 13

Hot pump

Question 14

What does “RAT PRESS” (green light) within the RAT switch indicate?

Answer 14

Deployed and good hydraulic pressure

Question 15

What is the minimum airspeed for the RAT to develop adequate pressure?

Answer 15

130 Knots

Question 16

When is the PTU inhibited?

Answer 16

When the right engine has failed

Question 17

Pushing the reserve brake switch does what?

Answer 17

1. ) allows use of the reserve hydraulic fluid
2. ) activates the right electric hydraulic pump
3. ) isolates the right electric hydraulic pump power to the normal brake system

Question 18

How much fuel is required in the left main tank for hydraulic fluid cooling while on the ground.

Answer 18

4020 pounds

Question 19

Can the RAT be restowed once it has been deployed?

Answer 19

No

Question 20

What happens to the hydraulic system when the fire handle is pulled?

Answer 20

Closes the engine hydraulic supply valve

Depressurizes the engine driven pump

Question 21

What hydraulic system uses the RAT?

Answer 21

Center

Question 22

What is the lowest airspeed in which the RAT can provide adequate hydraulic pressure?

Answer 22

130 Knots

Question 23

How do you know that the RAT is providing adequate hydraulic pressure?

Answer 23

The green RAT PRESS light illuminates

Question 24

What does an illuminated hydraulic pump “OVHT” light mean?

Answer 24

The pump is overheated

Question 25

Which hydraulic system has fluid dedicated for reserve brakes?

Answer 25

Right

Question 26

Can the RAT automatically deploy?

Answer 26

Yes, anytime both engines fail above 80 knots

Question 27

What will cause the PTU to operate?

Answer 27

Left engine failure or left engine hydraulic pump low pressure

Question 28

What does the PTU operate?

Answer 28

Flaps Slats Landing gear Nose wheel steering

Question 29

What electric bus controls the RAT?

Answer 29

Hot Battery Bus

Question 30

The “UNLKD” light on the RAT indicates

Answer 30

The RAT is not stowed

Question 31

Hydraulic system overfill is indicated by?

Answer 31

Magenta OF

Question 32

Low hydraulic system s indicated by?

Answer 32

Magenta RF

Question 33

What is the normal service level for a full reservoir?

Answer 33

1.00

Question 34

When will the left and right hydraulic pumps operate with ac power available?

Answer 34

Continuously with switches on

Question 35

Which systems are controlled by all three hydraulic systems?

Answer 35

Flight controls

Question 36

Which hydraulic system powers high load components?

Answer 36

Left

Question 37

Which hydraulic system provides pressure to the alternate brakes?

Answer 37

Left

Question 38

What is the purpose of the left hydraulic system reserve fluid?

Answer 38

To supply the PTU

Question 39

Which hydraulic system uses two electric motor driven pumps?

Answer 39

Center

Question 40

Which systems are powered by the center hydraulic system?

Answer 40

Flight controls only

Question 41

What is the purpose of the center hydraulic system reserve fluid?

Answer 41

Fluid for the RAT

Question 42

Which hydraulic system is supplied by the RAT?

Answer 42

Center - Primary Flight Controls

Question 43

In flight, what causes the RAT to deploy automatically?

Answer 43

Both engines fail

Question 44

What is the meaning of the green “PRESS” light in the RAT switch?

Answer 44

RAT is deployed and is producing adequate pressure

Question 45

Which hydraulic system provides pressure to the normal brakes?

Answer 45

Right

Question 46

Which brake system is active during a single engine taxi with all pumps on?

Answer 46

Normal Brakes

Question 47

What is the reserve fluid in the right reservoir used for?

Answer 47

Reserve Brakes