S 796-051
 (1)  METHOD 1 - Leak Check With Fuel
________
 WARNING: USE THE TAIL SUPPORT EQUIPMENT IF YOU CANNOT KEEP THE
_______ CENTER OF GRAVITY IN THE LIMITS GIVEN BY THE WEIGHT AND BALANCE MANUAL. IF THE AIRPLANE CENTER OF GRAVITY IS NOT IN THESE LIMITS, THE AFT END OF THE AIRPLANE CAN ROTATE DOWNWARD AND HIT THE GROUND.
 (a)  
Install the tail support equipment if you cannot keep the airplane center of gravity in the limits given by the weight and balance manual (AMM 07-11-08/201).

 (b)  
Make sure the No. 1 or 4 main tanks are completely full.

 NOTE: This will make sure the boost pump conduit is
____
 covered with fuel.

 1)  Refuel or transfer fuel as necessary (AMM 12-11-01/301) (AMM 28-26-00/201).
 (c)  Wait for 5 minutes.
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747-400 MAINTENANCE MANUAL
 (d)  
Check both ends of the conduit for fuel leaks.

 (e)  
As an alternate procedure, pull a clean cloth through the conduit with a string.

 (f)  
Check for signs of fuel leakage.

 (g)  
If there is no fuel leakage in the conduit, then do these steps: 1) Do a leak check of the conduit every 500 flight hours. 2) Replace the conduit within 6000 flight hours, or 18 months,

 whichever comes first (AMM 28-22-06/401).

 (h)  
If there is fuel leakage in the conduit, then replace the conduit immediately (AMM 28-22-06/401).

 S 796-053
 (2)  METHOD 2 - Leak Check With Air Pressure
________
 NOTE: This procedure can be done with any amount of fuel in the
____
 tank.

 (a)  
Use the necessary fittings to plug one end of the conduit.

 (b)  
Connect a pressure gage and air supply source to the other end of the conduit.

 (c)  
Pressurize the conduit to 20 psig.

 (d)  
Close the shutoff valve on the pressure check equipment.

 (e)  
Monitor the pressure gage for 5 minutes.

 (f)  
If there is a significant air pressure drop, then replace the conduit immediately (AMM 28-22-06/401).

 (g)  
If there is not a significant air pressure drop after 5 minutes, then do these steps: 1) Do a leak check of the conduit every 500 flight hours. 2) Replace the conduit within 6000 flight hours, or 18 months,

 whichever comes first (AMM 28-22-06/401). 3) If there is a significant air pressure drop, then replace the conduit immediately (AMM 28-22-06/401).
 S 936-055
 (3)  
Make a record of the conduit wiring inspection results (Table 601).

 S 426-054

 (4)  
After you satisfactorily complete the necessary conduit check/rework, then continue with the installation of the boost pump conduit wire bundle.

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747-400
MAINTENANCE MANUAL

 ~.............................................................................. | Fuel Boost Pump Conduit Wiring Inspection Record | ................................................................................ |Aircraft NBR: | | | ................................................................................
 |Total Accumulated  |Total Flight Cycles:  |
 |In-service Hours:  |  |
 |  |  |

 ................................................................................ | COMPONENTS | SATISFACTORY/UNSATISFACTORY COMMENTS | ................................................................................ |M1 Forward Boost Pump Conduit Wiring | | | | | | | | ................................................................................ |M1 Forward Boost Pump Conduit Sleeving| | | | | | | | ................................................................................ |M1 Aft Boost Pump Conduit Wiring | | | | | | | | ................................................................................ |M1 Aft Boost Pump Conduit Sleeving | | | | | | | | ................................................................................ |M4 Forward Boost Pump Conduit Wiring | | | | | | | | ................................................................................ |M4 Forward Boost Pump Conduit Sleeving| | | | | | | | ................................................................................ |M4 Aft Boost Pump Conduit Wiring | | | | | | | | ................................................................................ |M4 Aft Boost Pump Conduit Sleeving | | | | | | | | 2......................................….......................................1
　
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