HYDRAULIC SYSTEM Flashcards
When will the demand pumps be commanded to operate if the hydraulic demand pump selector is in the AUTO position?
When respective engine pump output pressure is low, or when fuel control switch is in CUTOFF.
Demand pumps 1 and 4 also operate when trailing edge flaps are in transit or in flight when flaps extend past 1.
What does the hydraulic system (SYS FAULT) fault light indicate?
Low Hydraulic system pressure.
Low hydraulic reservoir quantity.
Excessive hydraulic fluid temperature.
What does a hydraulic demand pump low PRESS light indicate?
Demand pump selector positioned to OFF or AUX.
Demand pump commanded to operate and output pressure is low.
What does a hydraulic reservoir quantity indication of .80 mean, as displayed on the Secondary EICAS display?
Hydraulic reservoir quantity is 80%
What does a magenta “RF” displayed next to a hydraulic quantity indicator on the Secondary EICAS mean?
Reservoir requires refill.
When is the engine driven hydraulic pump pressurized?
When the engine is running and the engine pump switch is on.
Which demand pumps are air driven, and which ones are electric motor driven?
1 & 4 air driven demand pumps.
2 & 3 electric motor demand pumps.
What is the purpose of the auxiliary pump?
For ground handling operations.
Why are the hydraulic reservoirs pressurized by the bleed air system?
To prevent pump cavitation and ensure positive flow during high demand conditions.
How does pulling a fire switch affect the hydraulic system?
Hydraulic fluid shutoff valve closes,
EDP depressurises.
Respective demand pump operates.
What are some examples of major system components powered by each hydraulic system?
1,2 & 3 ; C, R, L autopilot servos. 2,3 & 4 spoilers 1 & 4 trailing edge flaps, LG, redundant power to primary flight controls. 1 & 2 alternate brakes 1 steering 4 normal brakes.
