(3)  
25-22-01/401, Main Passenger Cabin Ceiling Access Panels

 (4)  
IPC 21-58-02 Fig. 1

 (5)  
WDM 21-58-17

 (6)  
SSM 21-58-02

 B. Access
 (1)  Location Zone 121 Forward Cargo Compartment Forward Half, RH 211 Passenger Cabin Nose to First Door, LH
 C. Install the Detector
 S 432-009
 (1)  Remove the cover from the duct opening.
 (a) Make sure there is no unwanted material in the duct.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 21-58-02
 ALL  ú ú 02 Page 206 ú Feb 18/00
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A
747-400 MAINTENANCE MANUAL
 S 432-027
 (2)  
Put a new O-ring on the detector.

 S 432-042

 (3)  
Install the dripshield.

 S 422-010

 (4)  
Install the detector.

 S 432-011

 (5)  
Install a lockwire on the detector (Ref 20-11-28/401).

 S 432-012

 (6)  
Connect the electrical connector to the detector.

 (a)  
Forward rack detector DM7934

 (b)  
Flight deck detector DM7933

 D.  Do the Installation Test for the Detector.
 S 862-013
 (1)  Do the Detector Ground Test (Ref 21-58-00/501).
 E.  Put the Airplane to Its Usual Condition
 S 412-028
 (1)  If you installed the flight compartment detector, do the step that follow:
 (a)  Install the inboard-most dripshield on the left side of the airplane centerline: 1) Put the inboard-most dripshield into its position. 2) Install the two fasteners (screw, washer, and gasket) on
 the lower side of the inboard-most dripshield to attach it
 to the structure.
 3)  Install the four fasteners (screw, nut, and two washers) on the upper side of the innboard-most dripshield to attach it to the other dripshields.
 4)  Connect the four drain tubes to the inboard-most dripshield.
 (b) Install the ceiling access panel (Ref 25-22-01/401).
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

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 ALL  ú ú 02 Page 207 ú Jun 10/96
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 FAN CHECK VALVES - REMOVAL/INSTALLATION
_______________________________________
 1.  General_______
 A.  This procedure has instructions to remove and install the check valves for the equipment cooling fans. The check valve for the supply fan is installed in the left sidewall of the forward cargo compartment at station 560. The check valve for the exhaust fan is installed below the floor of the forward cargo compartment at Station 500.
 TASK 21-58-03-004-001
 2.  Fan Check Valve Removal (Fig. 401)_______________________
 A.  References
 (1)  
AMM 24-22-00/201, Manual Control

 (2)  
AMM 25-52-01/401, Containerized Cargo Compartment Ceiling and Sidewall Linings

 (3)  
AIPC 21-43-52 Fig. 2

 (4)  
AIPC 21-58-03 Fig. 1

 B.  Access
 (1)  Location Zone 121 Forward Cargo Compartment Forward Half, LH 122 Forward Cargo Compartment Forward Half, RH
 C.  Prepare for the Removal
 S 864-002
 CAUTION: DO NOT OPERATE THE ELECTRICAL/ELECTRONIC EQUIPMENT WHEN YOU DO THIS
_______ PROCEDURE. IF YOU OPERATE THE ELECTRICAL EQUIPMENT WHEN THE EQUIPMENT COOLING SYSTEM IS NOT ON, YOU COULD CAUSE THE ELECTRICAL EQUIPMENT TO BECOME TOO HOT.
 (1)  
Remove the electrical power (AMM 24-22-00/201).

 S 014-003

 (2)  
To get access to the check valve for the supply fan,
 do the steps that follow:

 (a)  Remove the left sidewall of the forward cargo compartment at Station 565 (AMM 25-52-01/401).
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