LEAKAGE LOCATION  STAIN  SEEP  SEEP HEAVY  LEAK RUNNING 
wing surfaces that do not have fairings. Open areas with a good flow of air where fuel leakage cannot move to a possible fire source. Example: upper and lower 
 
 
 
 

Areas that are not fully closed and do not
1

have a good flow of air.  Example: rear  Two 
spar at the trailing edge flaps, front  locations 
spar at the leading edge flaps or slats,  maximum 
and the wheel wells. 

3
One location maximum
4
No repair procedure is necessary. Examine the fuel leak frequently to make sure it does not get larger.
It is not necessary to repair the fuel leak immediately. Examine the fuel leak frequently to make sure it does not get larger. Make the necessary repairs during the next applicable scheduled maintenance.
Repair the fuel leak immediately to a minimum of
or classification. Repair the fuel leak immediately. No fuel leakage is permitted.

Closed areas without a flow of air. Example: wing lower surface with fairings, air conditioning bay, wing/body fairings, and front and rear spars with fairings or panels.
Exterior empty space of the fuel boost pump.
Pressurized area of the wing center section tank.

Fuel Leak Repair Evaluation
Figure 602

EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A84448
A
747-400
MAINTENANCE MANUAL

 E. Access
 (1)  
Location Zones
 130 Center Wing Tank
 500 Wing Tanks, Left
 600 Wing Tanks, Right

 F.
Prepare the Airplane to Find the External Fuel Leak(s)

 S 656-093
 (1)  Refuel the fuel tanks if necessary (AMM 12-11-01/301).
 NOTE: To find all of the fuel leaks, make sure the fuel
____
 tanks are completely full.

 NOTE: If it is not possible to refuel the tank (tanks empty), use
____ air pressure to pressurize the fuel tank cavity. To find external leaks, use the air pressure and bubble solution procedure.
 S 486-144
 WARNING: DO THE PROCEDURE IN AMM 32-00-30/201 TO INSTALL THE DOOR LOCKS.
_______ THE DOORS OPEN AND CLOSE QUICKLY AND CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.
 (2)  If the leak is in the landing gear wheel-well area, install the door locks for the wing and body landing gear (AMM 32-00-30/201).
 S 046-149
 WARNING: DO THE PROCEDURE IN AMM 27-81-00/201 TO DEACTIVATE THE LEADING
_______ EDGE FLAPS. ACCIDENTAL OPERATION OF THE FLAPS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (3)  If the leak is near the front spar, extend the leading edge slats and do the deactivation procedure (AMM 27-81-00/201).
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 ALL  ú ú 03 Page 604 ú Oct 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 046-148
 WARNING: DO THE PROCEDURE IN AMM 27-51-00/201 TO DEACTIVATE THE TRAILING
_______ EDGE FLAPS. ACCIDENTAL OPERATION OF THE FLAPS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (4)  
If the leak is near the rear spar, extend the trailing edge flaps to get access to the area with the leak and do the deactivation procedure (AMM 27-51-00/201).

 S 016-151

 (5)  
Remove the necessary panels to get access to the fuel tank.

 G.
Find the External Fuel Leak

 S 796-160
 (1)  
Find the exact location of the external leak on the airplane skin (Fig. 603 and 604).

 S 796-154

 (2)  
Do these steps to prepare the external leak area:

 (a)  
Clean the external wing surface around the fuel leak area.

 (b)  
Use solvent to remove the grease from the area.
　
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