S 434-009

 (3)  
Install the screws in the overhead outlet flange. Tighten the screws.

 D.
Do the installation test for the overhead outlet.

 S 864-011
 (1)  
AIRPLANES WITH PASSENGER CONFIGURATION;
 Remove the DO-NOT-OPERATE tags from the L and R RECIRC FAN
 switch-lights, on the P5 panel.

 (a)  
Push the switch-lights to the on position.

 (b)  
Make sure the ON lights come on, and the INOP lights go off.

 S 214-010
 (2)  
Feel for the airflow from the overhead outlet.

 E.
Put the airplane back to its usual condition.

 S 864-012
 (1)  
Remove the DO-NOT-OPERATE tags from the L and R PACK selectors, on the P5 panel.

 (2)
Remove the electrical power, if it is not necessary (Ref 24-22-00).

 S 864-013
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 21-22-03
 ALL  ú ú 01 Page 403 ú Jan 28/02
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
757 MAINTENANCE MANUAL
 PASSENGER CABIN CONDITIONED AIR DISTRIBUTION -
______________________________________________ DESCRIPTION AND OPERATION
_________________________
 1.  General (Fig. 1)_______
 A.  The passenger cabin conditioned air distribution system channels air from the mix manifold (AMM 21-21-00/001) throughout the passenger cabin. The distribution system provides a comfortable environment for the passengers. The distribution system consists of sidewall risers, overhead ducts, overhead outlets, sidewall outlets, and return air grills.
 B.  Conditioned air from the mix manifold mixes with trim air and enters four sidewall risers (two on each side). The air then flows through each sidewall riser into the overhead duct. Air is dispersed into the passenger compartments from the overhead duct through overhead outlets located along the overhead duct, and sidewall outlets located under the stowage bins. Gasper outlets, connected to the overhead ducts, disperse conditioned air into each lavatory. Adjustable outlets disperse conditioned air into the galley areas. Air exits the passenger cabin through the return air grills located in the sidewalls near the floor.
 2.  Component Details_________________
 A.  Ducts
_____
 (1)  
Sidewall Riser Ducts

 (a)  
The sidewall risers are rectangular, 1.5 by 17.5 inch ducts located in the wall lining of the passenger compartment, just aft of the wing leading edge. Three-ply Kevlar and a thick honeycomb wall make up the riser ducts.

 (2)  
Overhead Duct

 (a)  
The overhead ducting extends the full length of the passenger cabin. The ducts are made of rigid plastic foam. Adaptor assemblies attach the main overhead duct to each overhead outlet.

 (3)  
Sidewall Outlet Ducts

 (a)  
The sidewall outlets are attached to the main overhead duct by smaller, 1.5 inch diameter flex ducts. The ducts are made of silicone rubber-impregnated fiberglass.

 B.  
Return Air Grills

__________________
 (1)  
The return air grills are made of a molded plastic screen with 2 clips on the top and 2 screws on the bottom to attach them to the carpet risers. The screens have 8 or 23 air vents that are about 1/4 inch wide and 14 inches long.

 (2)  
The air vents in the return air grill allow air to escape from the passenger compartment into the lower lobe of the airplane. This allows air to recirculate and to leave the passenger compartment if there is a rapid decompression.

 C.  
Outlets

_______
 (1)  
Overhead Outlets

 (a)  
The overhead outlets consist of a flow divider and a blade inside a housing. The flow divider and blade break up the airflow to prevent drafts in the passenger compartment.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 21-23-00
 ALL  ú ú 11 Page 1 ú Jan 28/02
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
757
　
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