Hydraulics Flashcards
What is the minimum HYD reservoir quantity?
.75 RF
Why is the demand pump powered by electricity?
Redundancy. Different source of power ensures HYD
With dual engine failure, how do we still have control of the Primary Flight Controls?
RAT deploys
Whats the minimum Hydraulic quantity for dispatch?
No RF
What’s the difference between the C and the L/R reservoirs?
C has stand pipe
What’s the purpose of C Reservoir stand pipe?
Capture fluid for reserve brakes and steering
Where is the RAT located?
where the wing meets the fuselage on the right side
What Systems utilise only the Left Hyraulics?
Primary Flight Controls
Rudder Ratio Changer
What systems utilise only the Right Hydraulics?
Primary Flight Controls
Normal Brakes
PES
What systems utilise only the Centre Hyraulics?
Flight Controls
Flaps/Slats
Tail Skid
HDG
Alternate Brakes
Nose Steering
Grear Accuator Up and Dow
Which hydraulic systems power the Spoilers?
Left Wing (outboard to inboard) 1-6
L, R, C, C, C, L
Right Wing (Inboard to outboard) 7-12
L, C, C, C, R, L
******Confirm
Which hydraulic systems power the Stabiliser?
L + C
Which hydraulic systems power the Yaw Damper
R power by the L
L powered by the C
Which hydraulic system powers the ailerons?
Outboard powered by the L + R
Inboard Left powered by the L+C
Inboard Right powered by the R+C
How does the Elec C1 pump provide fluid when quantity below standpipe?
One way check valves
What is the minimum HYD quantity for dispatch?
0.75RF
Why do the C1 ISLN valves close, with fluid below the standpipe?
Ensure reserve brakes and steering
What conditions need to be met for the RAT to deploy in flight:
Main gear logic needs to be met
Powered by Main Bettery Bus
80kts armed
Both engines below idle N2
How do you know the RAT deployed?
UNLKD light illuminated
How is the RAT manually deployed?
Hot Battery Bus
Push Button
What does the Green PRESS light indicate?
RAT producing HYD pressure for flight controls. >130kts
When selecting the R HYD electric demand pump AUTO what needs to be checked?
System low pressure light OFF
Demand pump light OFF
Brake source light OFF
3000PSI
How can brake pressure be increased on the ground?
Turn on the R electric demand pump
What is checked as the C2 pump is selected on?
System low pressure light OFF
C2 pump light OFF
What is checked as the C1 pump is selected on?
Check the C1 pump light out only
When selecting the L HYD electric demand pump to AUTO, what will you see?
C2 pump on
Galley Shed
How are yaw dampers controlled?
Electrical control – Normal AC power
Hydraulically actuated
In the event of a normal AC power failure, how does the Boeing logic power the Yaw dampers?
Standby AC bus
What is needed for the yaw dampers to work correctly?
1 IRU
Electrical AC power
Centre (Left Yaw Damper) and Left (Right Yaw Damper) Hydraulic power
What will bring on a single Yaw damper INOP light?
Failure of Centre (Left Yaw Damper) and Left (Right Yaw Damper) Hydraulic power
What are the considerations for a Rudder Ratio changer failure at high/low speed?
High speed – large movement of control surface could damage airframe
Low Speed – full movement of control surface may not be available ie x-wind
What does the HYD OVHT light indicate?
Primary pump is overheating
What does the HYD ON/Pressure light indicate?
Primary Pump is On
When pump is on its putting out low pressure
What is the ELEC/AIR press/OVHT light indicating?
Electric/Air Demand Pump has overheated
Electric/Air Demand Pump pressure
The HYD selector does what?
Controls selection for the backup supply
In the auto position, When does the demand pump work?
High Demand
Low Pressure from the Primary pump
Boeing commands it
How are the flight controls moved?
Input to actuator moves HYD fluid to move surface
What happens with a Rudder Ratio changer as airspeed increases?
Boeing desensitises inputs from the pilot
When would you expect to see a door and disagree light with regards to the tail skid?
Alternate gear extension.
Alternate gear extension does close the doors after they open
How are the flaps and slats powered?
Electrically commanded - input to actuator moving HYD fluid through the flap control unit
Centre HYD system
What is asymmetry protection?
Prevents uncommanded roll
Available for LE and TE in normal mode
What protections are provided for TE flap in alternate flap extension?
None
What is slat disagree?
Flap/slat not in commanded position
What fluid is used to set the park brake?
Anti Skid Return fluid
When do the electric demand pumps work?
High demand
Low pressure
Boeing Logic
An example for high demand?
Landing gear or flap actuation
Example of low pressure for the electric demand pump?
AC Power failure
