Hydraulic System Flashcards
When will the demand pumps be commanded to operate if the hydraulic demand pump selector is in the auto position?
- when related engine driven pump (edp) output pressure is low
- When related fuel control switch is cutoff
- during periods of higher demand
- if the edp fails
- 1&4 operate when te flaps in transit
What does the hydraulic SYS FAULT light indicate
- low hydraulic pressure
- low reservoir quantity
- excessively high fluid temperature
What does a hydraulic demand pump low PRESS light indicate
- selector is OFF or AUX position
- demand pump is operating but output pressure is low
- demand pump has failed
What does a hydraulic reservoir quantity indication of .8 mean (secondary eicas)
80% fluid service level
What does the magenta FR displayed next to a hydraulic quantity indicator on the secondary Eicas mean?
Reservoir should be serviced (refilled) ground only
LO - displays anytime quantity low
When is the engine driven hydraulic pump pressurized?
EDP switch is ON
and
Associated engine is running
And
Associated engine fire switch is not pulled
Which demand pumps are air driven and which ones are electrically driven?
1&4 air
2&3 electric
What is the purpose of the auxiliary pump?
Elec motor on system 4
Ground handling prior to engine start
Aux pump runs until edp pressurized, does not trip off
Why are the hydraulic reservoirs pressurized by the bleed air system
Prevent pump cavitation
Ensure positive flow during high demand conditions
How does pulling a fire switch affect the hydraulic system?
- Closes hydraulic fluid shutoff valve
- depressurizes EDP
- demand pump operates (in AUTO)
(No sys fault light)
Hydraulic sys 1 major system components
Inboard trailing edge flaps
Body gear actuation
Body gear steering
Nose gear actuation
Nose gear steering
Alt brakes
1/2 L outboard aileron
1/2 L inboard aileron
L outboard elevator
1/2 L inboard elevator
Center autopilot servo
Hydraulic system 2 major components
Alt brakes
1/2 R inboard aileron
Spoilers 2,3,10,11
1/2 lower rudder
1/2 L inboard elevator
Lower yaw damper
1/2 elevator feel
1/2 stab trim
R autopilot servo
Hydraulic system 3 major components
1/2 R outboard aileron
1/2 of L inboard aileron
Spoilers 1,4,9,12
1/2 of upper rudder
1/2 R inboard elevator
Upper yaw damper
1/2 Elevator Feel
1/2 stab Trim
L autopilot servo
Hydraulic system 4 major components
1/2 R inboard Aileron
1/2 R outboard aileron
Spoilers 5,6,7,8
1/2 lower rudder
1/2 R inboard elevator
R outboard elevator
Outboard trailing edge flaps
Wing gear actuation
Norm brakes
Auto brakes
