AIRPLANE
OPERATIONS
MANUAL
PNEUMATICS
AIR CONDITIONING
AND PRESSURIZATION
REVISION 18
2-14-05
Page
1
Code
01
GENERAL
The pneumatic system can be supplied by the engines, APU or a
ground pneumatic source.
The APU or ground pneumatic source supplies the system prior to the
engine start. The engines normally supply bleed air for pneumatics
after engine start.
The air conditioning system receives air from the pneumatic system
and provides conditioned air to the cabin. The system is controlled by
two Environmental Control Units (ECU).
The pressurization system uses bleed air from the air conditioning
system to pressurize the airplane. Cabin pressure is controlled by
modulating the outflow valves. The system is controlled by an
automatic mode and has a manual back-up mode.
Cooling for rear and forward electronic compartments is provided by
the ventilation system.
System information and messages are presented on the EICAS.
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