(b)  
Install the fasteners to connect the unitized valve assembly to the oxygen box.

 (c)  
Install the mask hoses to the manifold outlets.

 (d)  
Install the pintels to the mask shutoff valves.

 S 414-013
 (5)  Install the oxygen box (Ref 35-21-19/401).
 S 864-014
 WARNING:_______OPEN THE SHUTOFF VALVE ON EACH OXYGEN CYLINDER SLOWLY. IF NOT, HIGH TEMPERATURES CAN OCCUR WHICH CAN START AN IGNITION WITH THE OXYGEN. THIS CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE AIRPLANE AND EQUIPMENT.
 (6)  Open the shutoff valve on each oxygen cylinder:
 (a)  Slowly turn the shutoff valve until it is fully open.
 NOTE: The shutoff valve can be closed by hand which is
____
 equivalent to 25 pound-inches.

 (b)  
Close the shutoff valve one-fourth of a turn.

 (c)  
Install a lockwire on the shutoff valve.

 NOTE: Use the 0.020 inch diameter copper lockwire
____
 (AMM 20-11-28/401).

 S 414-015
 (7)  Close the access panels to the oxygen cylinders which are attached by snaps and velcro tape.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 35-21-05
 ALL  ú ú 01A Page 404 ú Feb 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 OXYGEN MASK - REMOVAL/INSTALLATION
__________________________________
 1.  General_______
 A.  These tasks are included in this procedure:
 (1)  
Oxygen Mask Removal

 (2)  
Oxygen Mask Installation

 B.  The oxygen mask for the passenger service units (PSUs) are installed in each PSU oxygen box. Access to the oxygen mask is through the oxygen box door.
 TASK 35-21-06-004-001-003
 2.  Oxygen Mask Removal (Fig. 401, 402, 403)___________________
 A.  General
 (1)  The procedure is for one oxygen mask. Do the steps again for more oxygen masks if it is necessary.
 B.  Standard Tools and Equipment
 (1)  
Rod - Metal, 3/32 inch diameter

 (2)  
Caps and Plugs - Package of Clean, Protective

 C.  References
 (1)  
AMM 35-00-00/201, Oxygen

 (2)  
AMM 35-21-06/701, Oxygen Mask

 (3)  
AIPC 35-21-06

 D.  Access
 (1)  Location Zone
 200 Upper Half Fuselage

 E.  Procedure
 S 914-002-003
 (1)  
Read and obey the safety precautions and general instructions before you do the maintenance (AMM 35-00-00/201).

 S 014-003-003

 (2)  
Get access to the oxygen masks (Fig. 402).

 (a)  
Push a 3/32 inch diameter rod into the access hole and actuate the latch to release the oxygen mask door.

 (b)  
Permit the oxygen masks to fall free.

 S 024-004-003
 (3)  Remove the oxygen mask.
 (a)  
Disconnect the oxygen mask from manifold outlet.

 (b)  
Remove the pintel from the the mask shutoff valve.

 (c)  
Remove the oxygen mask from the oxygen box.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. FREIGHTERS ONLY ú

 35-21-06
 ú CONFIG ú 01 Page 401 ú Oct 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL

 S 034-005-003
 (4)  
Install the protective caps and plugs to the mask hose and the manifold outlet to prevent contamination of the system.

 S 104-006-003

 (5)  
Clean the oxygen mask before the oxygen masks are installed back into the oxygen box (AMM 35-21-06/701).

 TASK 35-21-06-414-007-003
 3. Oxygen Mask Installation (Fig. 401, 402, 403)
________________________
 A. General
　
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