T-45A UJPT, E2-C2, ADV, & IUT Eng-02
Engine
(b) Dump valve routes excess
Overlay 6
GTS air overboard
Dump Valve
Overlay 7
(c) GTS accelerates to 100% for
ENGINE Switch
engine starting when ENGINE
switch is momentarily set to
START
(4) When ENGINE switch is
Overlay 8
momentarily set to START, the
Start Valve
GTS accelerates, the start valve is
opened, the dump valve closes,
and the GTS supplies compressed
air to the ATS
(5) Shuts down after engine reaches
45% rpm
b.
ATS: air turbine starter output shaft
Overlay 9
drives engine N2 shaft through external
Air Starter
NOTE: The starting system does not
feed air into the engine.
(1) Sprag clutch allows engine to
overrun ATS upon engine start
c.
Start control unit
Overlay 10
Start Control Unit
(1) Sequences start cycle by
monitoring speeds of GTS, air
turbine starter, and engine
(2) Electrically off-loads DC generator
and HYD 2 system until engine N2
rpm reaches 45% to ease strain
on ATS
(3) Shuts down GTS, rotation advisory
light, and engine ignition when
engine N2 rpm reaches 45%
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