MAIN LANDING GEAR AND DOORS -DRAG BRACE, SIDE BRACE, AND LOCK LINK ASSEMBLIES
EFFECTIVITY BEJ ALL 32-10-00
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D633W101-BEJ Sep 05/2002
MAIN LANDING GEAR AND DOORS -TRUCK ASSEMBLY
General
Each main landing gear truck has these components:
*
Axles
*
Tow fittings
*
Brake rods
*
Wheels and tires
*
Brakes
*
Truck positioner actuator
*
Main gear steering components.
There are three axles on each MLG truck. A jacking point is under the center of the forward and aft axles.
A tow fitting is on the forward part of the MLG truck. There is also a tow fitting/jackpoint on the aft part of the MLG truck.
Brake rods attach the brakes to the MLG shock strut to prevent rotation.
The truck positioner actuator tilts the MLG truck up and down when the airplane is in the air. See the MLG extension-retraction section for more information on the truck positioner actuator (SECTION 32-32).
The main landing gear steering components steer the aft axle eight degrees left or right. See the main gear steering section for more information (SECTION 32-53).
EFFECTIVITY BEJ ALL 32-10-00
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D633W101-BEJ Sep 05/2002
MAIN LANDING GEAR AND DOORS -TRUCK ASSEMBLY
EFFECTIVITY BEJ ALL 32-10-00
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D633W101-BEJ Jan 05/2002
MAIN LANDING GEAR AND DOORS -SHOCK STRUT
Purpose
The main landing gear shock struts absorb landing forces and transmit vertical loads to the airplane structure.
Physical Description
The shock struts are standard forged steel air-oil shock absorbers. They have an inner cylinder which moves inside an outer cylinder.
Compressed dry nitrogen is in the upper part of the shock strut. BMS3-32 hydraulic fluid is in the lower part of the shock strut.
Torsion links on the aft part of the shock strut connect the inner and outer cylinders.
Shock Strut Seals
A static seal and a dynamic seal keep the nitrogen and the hydraulic fluid in the shock strut. The static seal is between the lower bearing and the outer cylinder. The dynamic seal is between the lower bearing and the inner cylinder.
There are two spare static seals in the shock strut. There are also two spare dynamic seals and dynamic seal backup rings in the shock strut. The spare dynamic seals and backup rings are on the spare seal carrier.
These permit change of faulty seals without removal of the inner cylinder.
Training Information Point
The dynamic seal is not the same as the spare dynamic seals. The spare dynamic seals are more flexible. This permits installation of the spare dynamic seals on to the larger diameter of the spare seal carrier.
A gas charging valve (not shown) is on the aft side of the MLG shock strut near the side brace lock links.
The oil charging valve is on the front of the shock strut forward of the upper torsion link.
A servicing chart (not shown) is on the main landing gear shock strut door.
CAUTION: WHEN SERVICING THE SHOCK STRUT WITH FLUID, USE ONLY THE FLUID SPECIFIED ON THE NAMEPLATE. FLUIDS WHICH ARE NOT COMPATIBLE OR OF THE WRONG TYPE WILL CAUSE THE SEALS TO DETERIORATE AND RESULT IN LEAKS.
WARNING: DO NOT REMOVE THE AIR VALVE BODY UNTIL THE SHOCK STRUT HAS BEEN DEFLATED. INTERNAL PRESSURE CAN BLOW THE VALVE OUT, CAUSING INJURY TO PERSONNEL.
EFFECTIVITY BEJ ALL 32-10-00
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D633W101-BEJ Sep 05/2002
777 AIRCRAFT MAINTENANCE MANUAL
MAIN LANDING GEAR AND DOORS -SHOCK STRUT
EFFECTIVITY BEJ ALL 32-10-00
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D633W101-BEJ Jan 05/2002
MAIN LANDING GEAR AND DOORS -MLG DOORS
General
These are the four main landing gear doors:
*
MLG body door
*
MLG drag brace door
*
MLG shock strut door
*
MLG trunnion door.
MLG Body Door
The body door closes over the MLG wheel well. Hinges attach the door to the MLG wheel well near the keel beam.
A hydraulic actuator opens and closes the body door during extension and retraction. See the MLG extension-retraction section for more information on the MLG door actuator (SECTION 32-32).
An uplock roller on the door slides into an uplock hook assembly to keep the main landing gear door closed. See the MLG extension-retraction section for more information on the MLG door uplock hook and MLG door lock actuator (SECTION 32-32).
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