757 Hydraulic System Flashcards
What is indicated by the hydraulic control panel “SYS PESS” light?
Low pressure in the associated hydraulic system
What is indicated by the “RSVR” light on the hydraulic control panel?
Low fluid quantity (less than 50%) or low pneumatic head pressure in the reservoir.
What does the amber “PRESS” light mean on an associated hydraulic pump?
Pump output pressure is low
What will happen if both center electric pumps are on and there is only one electrical source?
The right electric hydraulic pump will load shed
What does the “OVHT” light on the hydraulic control panel indicate?
An overheat in the associated pump case drain cooling
What happens when you turn off the engine driven hydraulic pump?
The associated engine driven pump is depressurized. This prevents pump output. Fluid continues to circulate through the pump for cooling and lubrication.
How many independent hydraulic systems?
Three
What systems are controlled by the left hydraulic system?
Flaps and slats Steer and gear Alternate brakes Flight controls Left thrust reverser Main cargo door Reserve fluid for PTU
What systems are controlled by the center hydraulic system?
Flight controls
Reserve fluid for RAT
What systems are controlled by the right hydraulic system?
Flight controls
Right thrust reverser
Normal brakes
Reserve fluid for reserve brakes
What does “SYS PRESS” light on the hydraulic control panel indicate?
Low pressure in the associated system
What does the “RSVR” light on the hydraulic control panel indicate?
Low quantity or head pressure
What does the “OVHT” light on the hydraulic control panel indicate?
Hot pump
What does “RAT PRESS” (green light) within the RAT switch indicate?
Deployed and good hydraulic pressure
What is the minimum airspeed for the RAT to develop adequate pressure?
130 Knots
When is the PTU inhibited?
When the right engine has failed
Pushing the reserve brake switch does what?
- ) allows use of the reserve hydraulic fluid
- ) activates the right electric hydraulic pump
- ) isolates the right electric hydraulic pump power to the normal brake system
How much fuel is required in the left main tank for hydraulic fluid cooling while on the ground.
4020 pounds
Can the RAT be restowed once it has been deployed?
No
What happens to the hydraulic system when the fire handle is pulled?
Closes the engine hydraulic supply valve
Depressurizes the engine driven pump
What hydraulic system uses the RAT?
Center
What is the lowest airspeed in which the RAT can provide adequate hydraulic pressure?
130 Knots
How do you know that the RAT is providing adequate hydraulic pressure?
The green RAT PRESS light illuminates
What does an illuminated hydraulic pump “OVHT” light mean?
The pump is overheated
Which hydraulic system has fluid dedicated for reserve brakes?
Right
Can the RAT automatically deploy?
Yes, anytime both engines fail above 80 knots
What will cause the PTU to operate?
Left engine failure or left engine hydraulic pump low pressure
What does the PTU operate?
Flaps
Slats
Landing gear
Nose wheel steering
What electric bus controls the RAT?
Hot Battery Bus
The “UNLKD” light on the RAT indicates
The RAT is not stowed
Hydraulic system overfill is indicated by?
Magenta OF
Low hydraulic system s indicated by?
Magenta RF
What is the normal service level for a full reservoir?
1.00
When will the left and right hydraulic pumps operate with ac power available?
Continuously with switches on
Which systems are controlled by all three hydraulic systems?
Flight controls
Which hydraulic system powers high load components?
Left
Which hydraulic system provides pressure to the alternate brakes?
Left
What is the purpose of the left hydraulic system reserve fluid?
To supply the PTU
Which hydraulic system uses two electric motor driven pumps?
Center
Which systems are powered by the center hydraulic system?
Flight controls only
What is the purpose of the center hydraulic system reserve fluid?
Fluid for the RAT
Which hydraulic system is supplied by the RAT?
Center - Primary Flight Controls
In flight, what causes the RAT to deploy automatically?
Both engines fail
What is the meaning of the green “PRESS” light in the RAT switch?
RAT is deployed and is producing adequate pressure
Which hydraulic system provides pressure to the normal brakes?
Right
Which brake system is active during a single engine taxi with all pumps on?
Normal Brakes
What is the reserve fluid in the right reservoir used for?
Reserve Brakes
