AIRPLANE
OPERATIONS
MANUAL
AUXILIARY
POWER UNIT
REVISION 37
2-09-05
Page
5
Code
01
AOM-145/1114
The pneumatic control system consists of a flow limiting venturi (for
APU Model T-62T-40C11 only), a bleed valve, and an anti-surge
valve. The flow limiting venturi maintains the bleed flow below a set
value, depending on air conditioning system requirements and
atmospheric conditions, thus maintaining the EGT within acceptable
levels. The anti-surge valve is controlled by the ESU (or FADEC),
which monitors the signal from the APU bleed valve, the Air Turbine
Starter (ATS) valve, and the Environmental Control System (ECS)
valve.
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