(b) To lift the airplane nose at the nose jack point VI (See Fig. 203), use one of the following tasks:
CAUTION: PUT HYDRAULIC FLUID IN THE STRUT TO EXTEND THE STRUT.
_______ DO NOT USE AIR OR NITROGEN BECAUSE TOO MUCH PRESSURE CAN CAUSE DAMAGE TO THE STRUT AT ITS FULL EXTENSION.
MAKE SURE YOU EXTEND THE NOSE STRUT BEFORE THE AIRPLANE IS LIFTED AT JACK POINT VI. WHEN THE NOSE IS LIFTED INDEPENDENTLY AND SUFFICIENTLY FOR TIRE CLEARANCE, UNUSUAL LOADS ARE CAUSED. JACK POINT VI WILL MOVE IN AN ARC ABOUT 3-1/2 INCHES AFT AND CAUSE LOADS THAT ARE MORE THAN THE DESIGN LIMITS. THE BEND FORCE OF THE JACK RAM IS LESS THAN THE BREAKAWAY FORCE THAT IS NECESSARY TO MOVE THE 16 MAIN LANDING GEAR TIRES. DURING SOME CONDITIONS, JACK DAMAGE AND DAMAGE TO THE AIRPLANE CAN OCCUR. THIS COULD MAKE THE RETRACTION OF THE JACK RAM NOT EASY OR NOT POSSIBLE.
1) Lift the nose of the airplane at jack point VI with over filling of the nose shock strut with oil.
NOTE: To do this task you will deflate the shock strut to
____ within 1 inch of the full extension, then lift the nose at jack point VI.
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C.
D.
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747-400 MAINTENANCE MANUAL
2) Lift the airplane nose at jack point VI with deflating the nose landing gear shock strut.
NOTE: To do this task you will deflate the nose landing
____
gear shock strut.
CAUTION: DO NOT USE THE SHOCK STRUT RETENTION TOOL ON INFLATED
_______ SHOCK STRUTS. THE RETENTION TOOL HAS A LOAD LIMIT.
(c) An optional method that can be used to perform maintenance on the nose landing gear and reduce the over all jacking height to acheive nose wheel clearance is to lift the airplane nose and use the retention tool for the shock strut and the body jacks at jack points I and II. The nose can also be lifted with the retention tool and the nose jack at jack point VI.
NOTE: Do this with a deflated shock strut.
____
NOTE: Do not install the retention tool when the nose landing
____
gear is going to be retracted.
(d) Lift the nose of the airplane with axle jacks.
NOTE: Use this task when you will not move the nose landing
____ gear, for example: removal and installation of the wheel and tire assembly.
(e)
When the airplane can not be lifted on jacks at jack points I and II, the nose strut must be extended to lift the airplane at jack point VI. Put hydraulic fluid in the nose shock strut until the strut is within 1 inch of its full extension. Put the jack at jack point VI and lift the jack until you get the recommended tire clearance.
(f)
A nose axle jack or an incline block can be used to do a wheel
or tire change (AMM 07-11-03/201).Special Tools and Equipment
(1)
6ME65B00161-1 Main Gear Ground Lock (4 required)
(2)
2ME65B01202-1 Nose Gear Ground Lock
(3)
8ME65B01202-3 Landing Gear Shock Strut Retention Tool
(4)
11MIT65B04012 Nose Landing Gear Door LockStandard Tools and Equipment
(1)
Equipment - Jacking
(2)
Pressure Gage - 0-3000 psi (accuracy of | 2-1/2%, graduations not
more than 100 psi apart, diameter not less than 4 inches)References
(1)
07-11-00/001, Lifting Airplane for Maintenance
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MAINTENANCE MANUAL
(2)
07-11-01/201, Jacking Airplane
(3)
09-11-00/201, Towing
(4)
12-15-05/301, Nose Landing Gear Shock Strut
(5) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 LIFTING AND SHORING(7)
