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nose wheel steering switch, the airplane must be on the ground
and there must be normal quantity in the hydraulic system B
reservoir.
See the nose wheel steering system section for more
information about the alternate nose wheel steering switch.
(SECTION 32-51)
LANDING GEAR CONTROL SYSTEM - FUNCTIONAL DESCRIPTION - HYDRAULIC
EFFECTIVITY
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LANDING GEAR CONTROL SYSTEM - FUNCTIONAL DESCRIPTION - HYDRAULIC
LANDING GEAR CONTROL SYSTEM - FUNCTIONAL DESCRIPTION - HYDRAULIC
EFFECTIVITY
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General
Hydraulic system A normally supplies pressure to extend and
retract the main landing gear. Hydraulic system B supplies
alternate pressure for retraction only. The landing gear transfer
valve controls the pressure source (hydraulic system A or
hydraulic system B) to supply the main landing gear.
The shimmy damper decreases main landing gear shimmy.
The shimmy damper is connected to the return line between the
landing gear selector valve and the landing gear transfer valve.
See the MLG and Doors section for more information about the
shimmy damper. (SECTION 32-10)
The landing gear selector valve supplies up or down pressure
to retract or extend the main landing gear. The landing gear
lever controls the landing gear selector valve.
WARNING: MAKE SURE ALL PERSONS AND EQUIPMENT ARE
CLEAR OF THE MAIN LANDING GEAR. FAST
MOVEMENT OF THE MAIN LANDING GEAR CAN
CAUSE INJURY TO PERSONS AND DAMAGE TO
EQUIPMENT.
Up pressure goes to the alternate and gear retract brake
system. This stops wheel rotation during main landing gear
retraction.
See the Wheels and Brakes section for more information about
the gear retract brake system. (SECTION 32-41)
Components
These are the main landing gear extension and retraction
components:
* Main landing gear actuator (2)
* Uplock mechanism (2) and uplock actuator (2)
* Downlock actuator (2)
* Transfer cylinder (2)
* Frangible fitting (2)
* Fuse (2).
MLG Actuator
The main landing gear actuator moves the gear up and down.
Uplock Mechanism and Actuator
The uplock actuator unlocks the uplock mechanism during
extension.
Downlock Mechanism and Actuator
The downlock actuator locks the main landing gear during
extension and unlocks the main landing gear during retraction.
MLG EXTENSION AND RETRACTION - GENERAL DESCRIPTION
EFFECTIVITY
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Transfer Cylinder
The transfer cylinder gives a time delay to permit the main
landing gear to unlock before the main gear actuator moves the
gear.
Frangible Fitting
The frangible fitting removes up pressure from the main landing
gear actuator when a damaged, spinning tire moves into the
main landing gear wheel well. This prevents damage to
components in the wheel well.
Fuse
The fuse prevents hydraulic system fluid loss when the
frangible fitting operates.
MLG EXTENSION AND RETRACTION - GENERAL DESCRIPTION
EFFECTIVITY
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MLG EXTENSION AND RETRACTION - GENERAL DESCRIPTION
MLG EXTENSION AND RETRACTION - GENERAL DESCRIPTION
EFFECTIVITY
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32-32-00-001
Retraction
This is the retraction sequence for the main landing gear:
* Landing gear control lever moved to UP
* Transfer cylinder strokes
* Downlock actuator extends
* Downlock mechanism unlocks
* Main landing gear actuator extends
* Main landing gear retracts
* Uplock roller moves into uplock mechanism
* Uplock mechanism locks
* Landing gear control lever moved to OFF.
When the landing gear control lever is in the UP position,
hydraulic pressure pressurizes the MLG up lines through the
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