F.
Install the Test Equipment (Fig. 603)

 S 846-206
 (1)  If you are scheduled to do a leak check of the refuel/jettison manifold or the CWT interconnect manifold, then do these steps:
 WARNING: CAREFULLY DO ALL THE SAFETY PROCEDURES TO GO INTO THE FUEL
_______ TANKS. INJURY TO PERSONS AND DAMAGE TO EQUIPMENT CAN OCCUR IF YOU DO NOT OBEY THE SAFETY PROCEDURES.
 (a)  
Purge the No. 2 and 3 main tanks (AMM 28-11-00/201).

 (b)  
Enter the No. 2 and 3 main tanks through these access doors (AMM 28-11-00/201): 1) 544AB Fuel Tank Access Door (MAIN 2) 2) 644AB Fuel Tank Access Door (MAIN 3)

 WARNING: ACCOUNT FOR ALL TOOLS AND ITEMS GOING INTO THE FUEL TANK.
_______ MAKE SURE ALL TOOLS HAVE ATTACHED "REMOVE BEFORE FLIGHT" FLAGS. IF YOU ACCIDENTALLY LEAVE A TOOL ATTACHED TO REFUEL MANIFOLD, DAMAGE TO THE FUEL SYSTEM CAN OCCUR.
 (c)  
Make a written record of all tooling or removed structure.

 (d)  
Get access to the No. 2 and 3 refuel manifold drain valves (AMM 28-21-03/401).

 (e)  
Install a G28019-3 clamp assembly on each of the manifold drain valves to seal the manifold.

 S 486-207
 (2)  
Do these steps to attach the pressure test equipment to the rear spar:

 (a)  
Remove the control pressure switch for the APU fuel boost pump, S538 (AMM 28-41-01/401) (View A).

 (b)  
Attach the G28021 test equipment to the pressure switch port (View B).

 (c)  
Attach an air pressure source to the G28021 test equipment.

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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 G. Engine Fuel-Feed Manifold - Leak Check
 NOTE:____Pressurize one segment of the manifold at a time. If the leak check is satisfactory, then open the next crossfeed valve and repeat the pressure check. Continue until you do the check with all of the crossfeed valves in the open position.
 S 786-209
 (1)  
To leak check the first segment, make sure all the crossfeed valves are in the closed position.

 S 786-157

 (2)  
Use the air pressure source to apply 5 psig (34 kPa) to the engine fuel-feed manifold.

 S 786-210

 (3)  
After the pressure stabilizes, increase the pressure to 40 psi (275 kPa).

 S 786-211

 (4)  
Close the shutoff valve on the test equipment.

 S 786-212

 (5)  
Monitor the pressure gage.

 S 786-213

 (6)  
After 10 minutes, record the indicated pressure from the pressure gage.

 S 786-214

 (7)  
Open the bleed valve slowly and let the pressure in the lines bleed to zero.

 (a)  
Put a container next to the bleed port on the test equipment to capture any fuel leakage.

 S 786-215
 (8) If the pressure remained the same or decreased by less than 1.5 psi
 (10.3 kPa) in 10 minutes, then the manifold segment is satisfactory.
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 28-22-07
 ALL  ú ú 02 Page 624 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 786-216
 (9)  
Continue the leak check:

 (a)
Open the crossfeed valves, one at a time in this sequence:

 NOTE: To open the crossfeed valves put the manual handle to
____ the OPEN position (AMM 28-22-01/401).
 1) FUEL CROSSFEED VALVE NO. 2
 2) FUEL CROSSFEED VALVE NO. 1
 3) FUEL CROSSFEED VALVE NO. 3
 4) FUEL CROSSFEED VALVE NO. 4

 (b)  Repeat the pressure check procedure for each segment of the fuel-feed manifold.
 S 786-217
 (10)
 If the results show the pressure remained the same or decreased by less than 1.5 psi (10.3 kPa) in 10 minutes, then the manifold is satisfactory.

 S 786-218

 (11)
　
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