Systems - Hydraulics Flashcards
What does the PRESS light mean on the RAT switch?
RAT is deployed and the C Hyd system PFC pressure is greater than 1500psi
When pressurizing the hydraulic system, which pump is turned on first and off last? Why?
Right demand pump on first and off last to prevent fluid transfer into the right system
What is the purpose of demand pumps?
To assist the primary pumps in high load situations
When will the demand pumps run?
- Right engine demand pump will run after engine start until after TO.
- The C1 and C2 center demand pumps run during flap extension on the ground, and at 60kts on the TO roll until gear retraction.
- During gear extension only one center demand pump activates.
- C1 and C2 demand pumps can only run one at a time if in the ON position.
What does the fault light mean?
High fluid temp or low pump press
Which systems have standpipes?
All three systems
What are these standpipes for?
To allow for the minimum fluid to remain for system operation
What systems receive hydraulic power from the RAT?
Center Hyd
What causes the BRAKE SOURCE light to illuminate?
When down to only the accumulator pressure with Center and Right HYD system pressures low
The center hydraulic system has how many demand pumps?
C1 and C2
What is their power source?
Bleed air
What other component of the HYD system uses bleed air?
HYD reservoirs for pressurization
Do both of these pumps operate simultaneously?
If in auto then yes during flap extension on the ground and for TO at 60kts to gear retraction
Which one will operate if both are turned on?
C1
On the ground which if any demand pumps run continuously?
Why?
The R system electric demand pump runs continuously after engine start for the Normal Brake system
Which demand pumps if any operate during T/O and LDG?
- T/O the L, R system demand pumps operate continuously, C1, C2 demand pumps turn on at 60kts
- LDG the L, R system demand pumps operate continuously, C1 normally operates during high loads and gear extension.
If center hydraulic quantity is low and airspeed is > 60 kts, what happens?
- Alternate brakes are isolated from the C system and remain operable using reserve fluid
- Nose gear actuation and steering are isolated until <60kts and pressure to the C sys flight control is low or the gear is selected down, both engines normal, both engine driven pumps are providing pressure.
Of the two center hydraulic system primary pumps, which one is load shed?
C2
Where can you find Hydraulic fluid quantity data?
Status page
On that page what do the following mean?
* LO
* OF
* RF
- LO (amber) quantity is low
- RF (white) needs refill and is inhibited inflight
- OF (white) reservoir is over full and is inhibited in flight
What will cause the main battery to power the standby electrical system instead of the RAT?
During load shedding while it is prioritizing Hyd Press
Can the RAT be deployed on the ground with the cockpit switch?
Yes
Name the hydraulic components for each of the three systems.
LEFT
* thrust reverser
* flight controls
CENTER
* altn/rsv brakes
* slats/flaps
* flight controls
* nose gear/main gear steering/actuation
RIGHT
* normal brakes
* brake accumulator
* thrust reverser
When will RTO braking operate?
Above 85kts
How can autobrakes be disengaged?
- pressing the brake pedals
- stowing the speedbrake handle
- manually position the switch
- advancing one thrust lever
What system provides deceleration data to the autobrake effort?
ADIRU
