737 Flight Crew Operations Manual
Engines, APU -
General Controls and Indicators
Boeing Proprietary. Copyright © Boeing. May be subject to export restrictions under EAR. See title page for details.
7.15.8 D6-27370-866-EGP
3 APU OVERSPEED Light
Illuminated (amber) –
• APU RPM limit has been exceeded resulting in an automatic shutdown
• overspeed shutdown protection feature has failed a self–test during a
normal APU shutdown
• if light is illuminated when APU switch is placed to OFF, light
extinguishes after 5 minutes
• light is disarmed when the APU switch is in OFF position.
4 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.
5 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.
6 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.
September 15, 2016
To Next Page
Loading...
