S 014-004
 (4)  
Open the right fan cowl panel (AMM 71-11-04/201).

 S 014-005

 (5)  
Remove the right core cowl panel (AMM 71-11-06/401).

 S 014-043
 WARNING: OBEY THE INSTRUCTIONS IN THE PROCEDURE TO OPEN THE THRUST
_______ REVERSERS. IF YOU DO NOT OBEY THE INSTRUCTIONS WHEN YOU OPEN THE THRUST REVERSERS, INJURIES TO PERSONS OR DAMAGE TO EQUIPMENT CAN OCCUR.
 (6)  
Open the right thrust reverser (AMM 78-31-00/201).

 S 014-006

 (7)  
Open the Mid Lower Strut (Forward) Access Door on the left side of the strut (AMM 54-62-00/201).

 E.
Remove the Precooler

 S 034-007
 (1)  Remove the four tubes (23, 24, 25, and 26) that go to the
 fan-air-modulating valve (Fig. 401, Sheet 4).

 NOTE: There are two tubes (25 and 26) in the fan-air-modulating
____
 valve supply pressure tube assembly.

 (a)  
Disconnect the three tubes (23, 24, and 26) from the fan-air-modulating valve.

 (b)  
Disconnect the two tubes (23 and 24) from the fan-air-temperature sensor.

 (c)  
Disconnect the two tubes (25 and 26) from the tee (33).

 NOTE:____The tee (33) connect to the fan air modulating valve supply pressure tube which is on the lower aft right side corner of the precooler.

 (d)  
Disconnect the tube (25) from the bulkhead fitting on the bottom of the strut. 1) Remove the tube (25).

 (e)  
Remove the clamps (27) if it is necessary to do the step that follows: 1) Remove the three tubes (23, 24, and 26) that go to the fan

 air modulating valve.
 S 034-008
 (2)  Remove the fan-air-modulating valve (AMM 36-12-04/401).
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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A
747-400
MAINTENANCE MANUAL

17. LINK
1. PRECOOLER
1. PRECOOLER
C
12. LINK  C D
D
16. LINK
B
B FWD LEFT UPPER FITTING
B B
RIGHT AFT LINK ASSY
D
LEFT AFT LINK ASSY C
E
17. LINK
14. WASHER 13. BUSHING
11. WASHER
15. BOLT 10. NUT
12.,16. LINK
1. PRECOOLER
20.
 BUSHING

21.
 WASHER

11. WASHER 13. BUSHING
C-C
10. NUT 22. BOLT 14. WASHER
15. BOLT
18. BARREL NUT 19. BARREL
RETAINER NUT
1. PRECOOLER  D-D
B-B
Engine Bleed Air Precooler Installation
Figure 401 (Sheet 3)

EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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A
747-400 MAINTENANCE MANUAL
7. COUPLING
DUCT
8. SEAL
1. PRECOOLER
F
24. FAN AIR TEMPERATURE SENSOR SIGNAL PRESSURE TUBE
23. FAN AIR TEMPERATURE SENSOR COOLING AIR TUBE
27.
 CLAMP

28.
 SCREW

3. WASHER
29. NUT
(2 LOCATONS)

25. FAN AIR MODULATING
VALVE SUPPLY PRESSURE
TUBE

SEE H
26. FAN AIR MODULATING VALVE SUPPLY PRESSURE TUBE
SEE I
G
SEE J
Engine Bleed Air Precooler Installation Figure 401 (Sheet 4)
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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A
747-400 MAINTENANCE MANUAL
 (3)  S 034-009Remove the clamps (27) if it is necessary to disconnect the wire bundle for the fan air modulating valve from the precooler.
 (4)  S 864-045Make sure the thrust reverser is deactivated.
 (5)  S 014-010Open the left fan cowl panel (AMM 71-11-04/201).
　
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