Landing Gear (Hydraulic) Flashcards
What is the gear actuated by?
Hydraulic power pack
What is the service valve beside the hydraulic power pack used for?
Hand pump actuation of the gear during ground maintenance operations
How many sections is the power pack divided into?
2
What are the two sections of the hydraulic power pack?
One section supplies the electrically driven hydraulic pump and the other supplies the hand pump
What annunciation illuminates when hydraulic fluid is low?
HYD FLUID LOW
How many hydraulic actuators are used in conjunction with the power pack for the gear to be extended and retracted?
3, one for each gear
When does the gear warning horn sound?
Flaps UP or APPROACH and either or both power levers retarded below approximately 85% N1.
Horn sounds and handle lights illuminate
Horn can be silenced by pressing the button
When else will the gear horn sound?
Flaps APPROACH regardless of power settings and neither can be cancelled
For normal retraction, when the safety switches sense an airborne condition and the LDG GEAR CONT switch is moved to UP, what does this do?
Completes circuits to the pump motor relay and up solenoid of the gear selector valve
How much power does the pump motor relay pull in to the hydraulic pump motor in the power pack?
28 VDC
Where is the fluid pressure directed to for gear retraction?
The retract side of all 3 gear actuators
At what PSI does the up lock pressure switch open & break the circuit to the pump motor relay to stop the pump motor?
2,775PSI
How does the gear stay retracted?
Pressure in the retract side
When will the uplock pressure switch close to re-establish the power circuit to the pump?
When system leakage drops the pressure to 2,475 psi
What locks the gear in the extended position?
Down lock mechanisms
