737 MAX Flight Crew Operations Manual
Engines, APU
Chapter 7
APU System Description
Section 30
MN-FLT-OH-201
7.30.1
30 APU System Description
APU System Description
File Highlight
Introduction
The auxiliary power unit (APU) is a self–contained gas turbine engine installed
within a fireproof compartment located in the tail of the airplane.
The APU supplies bleed air for engine starting or air conditioning. An AC
electrical generator on the APU provides an auxiliary AC power source.
APU Location
APU Operation
The APU starts and operates up to the airplane maximum certified altitude.
The APU supplies bleed air for both air conditioning packs on the ground or one
pack in flight. Both transfer buses can be powered on the ground or in flight.
APU Door
The APU air inlet door is located on the right side of the fuselage and is
automatically operated. The APU air inlet door has 3 positions, closed, flight open
(approximately 17 degrees) and ground open (approximately 45 degrees).
March 1, 2021
