MLG EXTENSION-RETRACTION -MLG SIDE BRACE AND DRAG BRACE DOWNLOCK ACTUATORS
Purpose
The side brace downlock actuator locks and unlocks the over-center toggles between the side brace lock links during extension and retraction.
The drag brace downlock actuator locks and unlocks the over-center toggles between the drag brace lock links during extension and retraction.
The MLG side brace downlock actuator and the MLG drag brace downlock actuator are identical and interchangeable.
Physical Description
The actuators are hydraulic cylinders. They extend to lock the toggles during gear extension. They retract to unlock the toggles during gear retraction.
Location
The head ends of the actuators attach to the upper lock links. The rod ends attach to the upper toggles.
EFFECTIVITY BEJ ALL 32-32-00
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MLG EXTENSION-RETRACTION -MLG SIDE BRACE AND DRAG BRACE DOWNLOCK ACTUATORS
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MLG EXTENSION-RETRACTION -MLG DOOR ACTUATOR AND MLG DOOR-OPERATED SEQUENCE VALVE
Purpose
The MLG door actuator opens and closes the main gear door during gear extension and retraction.
The MLG door-operated sequence valve controls hydraulic flow to the main gear uplock actuator and to the MLG retract actuator.
Physical Description
The MLG door actuator is a hydraulic piston-type actuator. The actuator extends to open the main gear door and retracts to close the MLG door. Flow restrictors in the extend and retract port unions control the rate of door operation. Snubbers in the rod end and head end of the actuator control actuator speed at the ends of the actuator travel. The dry weight of the MLG door actuator is approximately 72 pounds (32.7 kg).
The MLG door-operated sequence valve is a two-position valve -DOOR OPEN and DOOR NOT OPEN. A mechanical linkage from the main landing gear door operates the sequence valve. The mechanical linkage includes these components:
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Control rod
*
Input crank
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Input link
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Intermediate crank
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Valve link (not shown).
The MLG door-operated sequence valve weighs 4.6 pounds (2.1 kg).
Location
The head end of the MLG door actuator attaches to reaction links which attach to the keel beam. The rod end attaches to the landing gear door.
The MLG door-operated sequence valve is on the keel beam aft of the MLG door actuator.
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MLG EXTENSION-RETRACTION -MLG DOOR ACTUATOR AND MLG DOOR-OPERATED SEQUENCE VALVE
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MLG EXTENSION -MLG DOOR UPLOCK HOOK AND MLG DOOR LOCK ACTUATOR
Purpose When the door closes, the roller on the door engages the uplock
hook. The motion of the door and pressure in the door lock The MLG door uplock hook and MLG door lock actuator are part
actuator drive the uplock hook to the overcenter locked position. of the door uplock assembly.
The door uplock hook holds the main gear door closed.
The door lock actuator locks and unlocks the door uplock hook during landing gear door operation.
Physical Description
The uplock hook uses over-center locking to hold the door closed. Two springs keep the hook in this position.
The door lock actuator is a piston-type actuator. It retracts to unlock the uplock hook and extends to lock the uplock hook.
Location
The door uplock assembly is on the uplock support structure. This structure is on the outboard side of the wheel well and attaches to the wheel well ceiling.
Functional Description
To open the MLG door, the door lock actuator moves the door uplock hook to the unlocked position. This permits the roller on the door to move out of the hook and the door to open.
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MLG EXTENSION -MLG DOOR UPLOCK HOOK AND MLG DOOR LOCK ACTUATOR
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Purpose
The MLG uplock assembly holds the main landing gear in the UP position.
The MLG uplock actuator unlocks the main gear uplock assembly during gear extension.
The MLG uplock-operated sequence valve controls main landing gear door close operation.
Physical Description
The MLG uplock assembly uses over-center locking to keep the main landing gear up and locked. Two springs hold the uplock hook in this position.
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