737 MAX Flight Crew Operations Manual
Engines, APU -
Controls and Indicators
7.10.24
MN-FLT-OH-201
3
APU FAULT Light
Illuminated (amber) –
• a malfunction exists causing APU to initiate an automatic shutdown
• if light is illuminated when APU switch is placed to OFF, light
extinguishes after 5 minutes
• light is disarmed when APU switch is in OFF position.
4
APU LOW OIL PRESSURE Light
Illuminated (amber) –
• during start until the APU oil pressure is normal
• oil pressure is low causing an automatic shutdown (after start cycle is
complete)
• if light is illuminated when APU switch is placed to OFF, light
extinguishes after 5 minutes
• light is disarmed when APU switch is in OFF position.
5
APU Switch
OFF – normal position when APU is not running
• positioning switch to OFF with APU running trips APU generator off
the bus(es), if connected, and closes APU bleed air valve. APU
continues to run for a 60 second cooling period
• APU air inlet door automatically closes after shutdown.
ON – normal position when APU is running.
START (momentary) – positioning APU switch from OFF to START and
releasing it to ON initiates an automatic start sequence.
March 1, 2021