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747-400
MAINTENANCE MANUAL

GROSS WEIGHT IN POUNDS

480,000
470,000
460,000
450,000
440,000
430,000
420,000
410,000
400,000
390,000
380,000
370,000
360,000
350,000
340,000
330,000
320,000
310,000
300,000

Dynamic Airplane Jacking-Maximum Gross Weight Versus C.G.
Figure 202

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747-400 MAINTENANCE MANUAL
 S 582-007
 (6)  If engine and/or component removal will cause an asymmetric airplane condition, lift the airplane on jacks (Ref 07-11-07/201).
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747-400 MAINTENANCE MANUAL
 MOVE LANDING GEAR ABOVE PIT - MAINTENANCE PRACTICES
___________________________________________________
 1.  General
_______
 A.  This procedure contains one task. The task is to move the landing gear above a pit.
 B.  This procedure contains limits and instructions when you move the landing gear above the pit.
 TASK 07-11-06-582-001
 2.  Move Landing Gear Above Pit
___________________________
 A.  General
 CAUTION: YOU MUST FOLLOW THE JACKING WEIGHT AND CG LIMITS IN
_______ 07-11-01/201. IF YOU DO NOT OBEY THESE LIMITS, YOU CAN CAUSE DAMAGE TO EQUIPMENT OR THE AIRPLANE.
 (1)  
You can use a pit for these items that follow:

 (a)  
To make the landing gear replacement easier

 (b)  
To do a test of the retraction system for the landing gear

 (c)  
For operations at an overhaul base

 (d)  
To replace the inner cylinder of the shock strut.

 (2)  
For operations at an overhaul base, you can hold the airplane on jacks with all the landing gear above the pits. You can do maintenance on each landing gear or on landing gear in different combinations.

 (3)  
Use of pits during maintenance on one or two gears, while you hold the airplane with all the other gear has some limits. In general, do not use gears and jacks in combination to hold the airplane. This causes indeterminate load problem which includes hard points and air columns (springs). Hard points can easily become loaded with too much load and cause structural damage.

 B.  Reference
 (1)  
07-11-01/201, Jacking Airplane

 (2)  
09-11-00/201, Towing

 (3)  
12-15-03/301, Wing Landing Gear Shock Strut

 (4)  
12-15-04/301, Body Landing Gear Shock Strut

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 (5)  
12-15-05/301, Nose Landing Gear Shock Strut

 (6)  
32-09-02/201, Air/Ground Relay System

 C. Prepare the airplane to move the gear above the pit.
 S 582-002
 (1)  Put the airplane above the pit (Ref 09-11-00/201).
 D. Lift the Airplane on Jacks.
 S 862-008
 WARNING: YOU MUST PUT THE AIR/GROUND RELAY SYSTEM IN THE AIR MODE.
_______ AUTOMATIC OPERATION OF AIRPLANE SYSTEMS IN THE AIR MODE CAN CAUSE INJURY OR DAMAGE.
 (1)  Do the "Prepare Safety-Sensitive Systems for Air Mode Simulation" procedure (Ref 32-09-02/201).
　
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