Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

APU operations

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web


Active member
Nov 27, 2001
Help! I was looking for some info on Corporations who have aircraft with APU's. How do you have it in your ops books during the operations of the APU, do you have to be in the cockpit? Or can you get up and help load bags with the other pilot. If your company manual says it needs to be monitored, do you have to be right there, or if your close by good enough? Such as throwing bags ect...
I'm looking at it by an insurance thing. If it catches fire or something and damages the aircraft, both pilots are loading bags, are we neglecting the duties of monitoring the APU? Will the insurance company come after me to pay for the damage? Any info would be great..
Most aircraft flight manuals do not require any monitoring of APUs while running and most crews leave them up and running while away from the aircraft especially during summer.

Some APUs like the Solar are even authorized for operation in flight for backup electrical while the Garretts generally are not.

Most units have automatic shutdown in the event of high temp, oil press, fan speed, etc unlike jet engines which require human decision making to shut down. The biggest danger would be shedding a fan blade but wether the APU panel was monitored or not wouldnt make a difference.
Well first off, I think it is the other way around. Many Garrett APU's are usable in flight up to a certain altitude. Our Garrett APU is certified in flight up to 30,000ft. Many of the Solar APUs are used only on the ground. Some are certified for in-flight use but not usually as high an altitude...but that is not the topic here.

Our company does not require us to be in the cockpit during APU operation, but does require us to be in the aircraft area while it is being operated. (Either in cockpit, cabin, loading bags, etc, etc.)

Flydog is correct most if not all APU have an automatic shut down feature in the even of a fault, fire, etc. Also, I know with our Garrett APU, Garrett says to shut it down by using the overspeed fault test to ensure that is will shut down on it's own and that circuitry is functioning properly

In regards to the insurance company I can't speak from knowledge. But I would think as long as you are in the area of the aircraft during operation then you could not be held accountable. That is the insurance companies job...insuring the aircraft!

Happy flying!

The first place I would look for a limitation is the AFM. Each APU and application will be different. The APU in the Citation Excel (Allied Signal) has all the bells and whistles, like automatic fire protection/monitoring and inflight capability up to FL300, but it is NOT certified for unattended operation. Go figure!
Thanks for all your replays.
We operate both the Garrett and and Allied Signal. Even though Allied Signal has a automatic fire system, 7 seconds is a long time for me with a fire light on befor it fires. The Garrett APU don't have the auto Fire protection, that's where the problem comes in at is the legal term "monitored" and " unattended". Does that actully mean in the airplane or somewhere around the plane???? I seen operators run there apu on the ground while the crew are in the FBO talking to the front dest chick. I'm afraid that the insurance company will come back on the crew for neglect of operations of the unit if it causes damage, and we are sueing you for the damage for the aircraft.
I'm just trying to write a section in the compay ops manual on this subject where its ok for the crew to be in close around the aircraft and not in it.
Thanks again.

Latest resources