2016 PC Guide - Hydraulics - Main5 Flashcards
(34 cards)
What is normal system A pressure
3000 psi
What would hydraulic system A quantity indicate with a leak in the engine driven pump or its associated lines?
20%
due to standpipe
What would hydraulic system A quantity indicate with a leak in the electric pump or its associated lines?
0%
would lose all hydraulic fluid
With a loss of system A, what does the “A” Flight Control LOW PRESSURE light indicate?
Hydraulic pressure to the primary flight controls (Aileron, Elevator, and Rudder) is low due to the complete loss of system A.
comes on if pressure is less than 1300 psi
With loss of system A, what does the FEEL DIFF PRESS light indicate?
Indicates an excessive differential hydraulic pressure sensed in the elevator feel computer between hydraulic systems A & B.
What happens when you move the associated Flight Control switch to STBY RUD, as directed by the QRH?
The associated hydraulic NO LONGER powers the flight controls.
The Standby Rudder pump and PCU will power the rudder.
What caused the standby Hydraulic system to automatically activate?
1) Low pressure in hydraulic systems A and/or B with
- flaps extended, and..
- in flight or on the ground with wheel speed greater than 60 KIAS
NOTE: auto operation doe son deactivate the flight control low pressure light
NOTE: When airborne and the flaps are retracted, the standby pump shuts off and the valve closes (Standby Rudder ON light extinguishes)
2) Force Fight Monitor triggered
3) (CL) The rudder pressure reducer failed to change system A pressure (to the rudder PCU) to normal at 700’ RA on landing
What does the Force Fight Monitor System do?
Detects opposing pressure between main rudder PCU A and B actuators. If opposing force is detected, the Force Fight Monitor automatically turns on the Standby Hydraulic Pump and power the standby rudder PCU to provide the pilot with adequate rudder control.
What does the Rudder Pressure Reducer do and why?
Reduces system A pressure to the rudder PCU above 1000 ft RA to give the pilot more time to react to large rudder deflections. Pressure should be returned to normal at 700 ft RA on approach to landing.
NOTE: The NGs have a Rudder Pressure Limiter that performs a similar function by reducing both A & B pressure by 25% to limit full rudder authority in flight. This occurs at speeds above approx. 135 KIAS.
With a loss of the A system, what MAJOR aircraft systems will be affected, and what additional procedure will you eventually have to accomplish?
Landing Gear - Manual Gear Extension
With the loss of System A hydraulics, will the following systems be available upon landing?
- Braking
- Thrust Reverse
- Nose Wheel Steering
- Ground Spoilers
- Flight Spoilers
Braking - YES via normal brakes bowered by system B
Thrust Reverse - YES, at a slower rated due to being powered by Standby System
Nose Wheel Steering - YES via alternate steering powered by System B
Ground Spoilers - NO
Flight Spoilers - YES, 2 (NG) / 1 (CL) on each wing via the System B hydraulics.
Is the Alternate Nose Wheel Steering automatic.
NO
Alternate Nose Wheel Steering must be selected.
Is the selection of Alternate Nose Wheel Steering directed by the QRH?
YES
Where is the Alternate Nose Wheel Steering switch located?
The switch is located on the CAs forward instrument panel.
If the Alternate Nose Wheel Steering switch is set to ALT, can you tow the aircraft?
NO
The switch must be returned to NORM prior to the aircraft being towed.
Where can you find the maximum speed for the landing gear extension?
placard o the forward panel near the gear handle.
What is the normal B system pressure?
300 psi
What would Hydraulic B system quantity indicate with a leak in the engine driven pump or its associated lines?
0%
Has a standpipe, but remaining fluid is only sufficient for PTU
What would Hydraulic B system quantity indicate with a leak in the electric pump or its associated lines?
0%
Has a standpipe, but remaining fluid is only sufficient for PTU.
Is any residual fluid retained when the B quantity indicates zero?
If so, why?
Yes, for operation of the PTU.
In the event of a loss of the B hydraulic system, a small amount of fluid is retained (standpipe) for operation of the auto slats via the PTU.
NOTE: Hydraulic system A powers a pump that uses B fluid to move the auto slats to the full extend position if required.
With loss of system B, what does the B Flight Control LOW PRESSURE light indicate?
Hydraulic pressure to the primary flight controls (Aileron, Elevator, and Rudder) is low due to the complete loss of system B.
occurs at approx 1300 psi
With the loss of system B, what does the FEEL DIFF PRESS light indicate?
Indicates an excessive differential hydraulic pressure is sensed in the elevator feel computer between hydraulic systems A and B.
With loss of system B, dies the YAW DAMPER light illuminate?
NO, but the YD is inop.
Even though the yaw damper is inoperative, the Yaw Damper light will not illuminate until the B FLIGHT CONTROL switch is placed to OFF or STBY RUD.
With loss of system B, can the Yaw Damper be cycled OFF then ON to regain the system?
No, the Standby Yaw Damper con only be engaged if both Flight Control switches are placed to STBY RUDDER and the Yaw Damper switch is then placed to ON (NG)
