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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
UPPER
DRAG GEAR
STRUT ACTUATOR
LOWER DRAG STRUT
TRUNNION
LOCK
SIDE ACTUATOR
SIDE BRACE BRACE
UPPER DRAGSTEERING STRUTCYLINDER
NOSE GEAR
ACTUATOR
UPPER TRIPODLOWER DRAG BRACESTRUT TRUNNION
NOSE WHEEL
WELL DOOR
LOWER SIDE BRACETRIPOD BRACE (2 PLACES)
STEERINGTORSION CYLINDERLINKS
FWD
SHOCK STRUT TORSION LINKS LOCK
UPPER DRAG
ACTUATOR
STRUT
LOWER DRAG STRUT
GEAR EXTENDED (ON GROUND)
UP UPPER TRIPOD BRACE
NOSE GEAR ACTUATOR
NOSE WHEEL SHOCK
WELL DOOR STRUT STEERING TRUNNIONCYLINDER
GEAR RETRACTED
Nose Gear Mechanism
Figure 3
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A 747-400 MAINTENANCE MANUAL
SHUTOFF VALVE
SEE A PRESSURE SWITCH
SHOCK STRUT
SEE B
A SEE C GAGE TUBE PRESSURE
A A 1
AIR VALVE SHUTOFF VALVE PRESSURE GAGE TUBE
PRESSURE SWITCH SHOCK STRUT
SHOCK STRUT
GAGE PRESSURE FWD
A 2 AIR VALVE
1 2 Nose Gear Shock Strut Figure 4 (Sheet 1) AIRPLANES WITH SHOCK STRUT PRESSURE GAGE AIRPLANES WITHOUT SHOCK STRUT PRESSURE GAGE B 1
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
SPARE STATIC SEALS
RING
ONE-PIECE LOWER BEARING TWO-PIECE LOWER BEARING
A-A A-A
Nose Gear Shock Strut
Figure 4 (Sheet 2)
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
E06595
A
747-400
MAINTENANCE MANUAL
A. The nose gear shock strut is the main supporting member of the nose gear. The shock strut includes an inner cylinder and an outer cylinder, metering pin assembly, upper and lower orifice assemblies, and upper and lower cam assemblies. The shock strut is attached to the nose wheel well structure by trunnions which are a part of the outer cylinder.
B. The lower end of the inner cylinder has an offset integral axle housing, into which the nose gear one-piece axle is pressed. Replaceable sleeves over each side of the axle provide a mount for wheel bearings and prevent axles from damage. The fixed centering cam attached to the top of the inner cylinder mates with a similar cam in the outer cylinder when the inner cylinder extends. When these cams engage, the nose wheel attains a straight, forward position, ensuring proper placement in the wheel well on retraction. Alignment of the cams upon extension also assures that nose wheels will be straight-forward when landing.
C. The inner cylinder slides in and out of the outer cylinder on upper and lower bearings. Annular grooves in the lower bearing provide space for storage of spare seals. The spare seals are replacements for the active static and active dynamic seals. Three pins connect the bottom of the lower bearing to an adapter. The adapter contains grooves in which the active dynamic and active static seals are located. This arrangement positions the spare seals above the active seals allowing the spare seals to be bathed in fluid during the operation of the strut. This protects the spare seals from degradation until they are ready for use.
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