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• Exhaust
• Accessory Gearbox
Air Intake
The air intake is a screened rectangular inlet
located on the upper left side of the rear fuse-
lage above the engine pylon (Figure 6-3).
Intake air is used for both combustion and in-
ternal cooling of the APU. An intake drain is
routed to a port on the right underside of the
aft fuselage.
Compressor
The compressor section consists of a single-
stage centrifugal impeller and diffuser. The
compressor develops approximately 45 psi at
normal operating speed.
Combustion Section
The combustion section consists of a single,
annular, reverse flow combustion chamber
and single ignitor plug.
6-3
FOR TRAINING PURPOSES ONLY
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
FlightSafety
international
ACCESSORY
GEARBOX
AIR
INTAKE
EXHAUST
COMPRESSOR
SECTION
COMBUSTION &
TURBINE
SECTION
Figure 6-2. APU Major Sections
Figure 6-3. APU Air Intake