AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -OUTFLOW VALVE -FUNCTIONAL DESCRIPTION

EFFECTIVITY BEJ ALL  21-31-00 
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D633W101-BEJ  May 05/2002 

AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -REMOTE CABIN PRESSURE SENSOR

Purpose
The remote cabin pressure sensor measures cabin air pressure independently of the ASCPCs.
Physical Description
The sensor is an electronic device. It has an internal pressure sensor
Location
The remote cabin pressure sensor is in the main equipment center below the P310 standby power management panel.
The remote cabin pressure sensor mounts with the pressure sense port down. This keeps air velocity effects to a minimum.
The central maintenance computing system (CMCS) does not test the remote cabin pressure sensor.
EFFECTIVITY BEJ ALL  21-31-00 
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D633W101-BEJ  Sep 05/2002 

AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -REMOTE CABIN PRESSURE SENSOR

EFFECTIVITY BEJ ALL  21-31-00 
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D633W101-BEJ  May 05/2002 

AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -BLEED AIR/PRESSURIZATION PANEL

Bleed Air/Pressurization Panel
These controls are on the bleed air/pressurization panel:
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Forward and aft outflow valve switches

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Forward and aft outflow valve manual switches

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Landing altitude selector.

Outflow Valve Switches
The forward and aft outflow valve switches set the outflow valves to automatic or manual operation. The switches are alternate-action switches. The AUTO indication on the switch shows the valves in automatic operation. When the MAN indication shows, the valves are in manual operation. In the MAN position, the ECS (environmental control system) data block shows on the EICAS display. The selection of the MAN position causes these indications:
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The related advisory message, OUTFLOW VALVE FWD (AFT) shows on the EICAS display

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The caution message, CABIN ALTITUDE AUTO shows on the EICAS display if both valves are set to MAN

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An M shows on the related valve position indicator in the ECS data block

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MAN shows below the valve position data on the air supply maintenance page (not shown).

Outflow Valve Manual Switches

The forward and aft outflow valve manual switches set the position of the outflow valves. The switches are toggle type switches with a spring-loaded center off position. These switches only function when the outflow valve switches are in the MAN position. Valve position shows in the ECS data block.
Landing Altitude Control
When the knob on the landing altitude selector is in, the ASCPC uses landing altitude data from the flight management computing function (FMCF) of AIMS.
When the landing altitude selector is out, the ECS data block shows and MAN shows next to the landing altitude data. MAN also shows on the air supply maintenance page (not shown) next to the landing altitude data. The landing altitude selector sets the landing altitude value. The ASCPC uses this value for landing altitude.
The flight crew moves the landing altitude control to the right to increase or to the left to decrease the landing altitude. The control is spring-loaded to the center position. The landing altitude limits are 2,000 feet below sea level to 15,000 feet above sea level.
Training Information Point
One outflow valve can operate in automatic mode and the other can operate in manual mode at the same time.
EFFECTIVITY BEJ ALL  21-31-00 
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D633W101-BEJ  Sep 05/2002 

AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -BLEED AIR/PRESSURIZATION PANEL

EFFECTIVITY BEJ ALL  21-31-00 
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D633W101-BEJ  Jan 05/2002 

AIR CONDITIONING -CABIN PRESSURE CONTROL SYSTEM -FUNCTIONAL DESCRIPTION

General
The air supply cabin pressure controllers (ASCPCs) supply control, indications, and BIT for the cabin pressure control system. ARINC 429 buses connect the ASCPCs to their related valve control unit (VCU) channels. The left and right VCU channels get power from a different bus. The outflow valve switches on the bleed air/pressurization panel set automatic or manual mode.
The ASCPCs have these modes of operation:
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Initialization (power up)

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Preflight BIT

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Automatic.

Initialization
The initialization mode runs when the ASCPCs first get power or when you install new software.
When the initialization mode is on, the ASCPCs do a check of these components and functions:
　
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