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APU  
User currently offlineBACONCORDE From United States of America, joined May 2000, 100 posts, RR: 0
Posted (13 years 3 days 20 hours ago) and read 747 times:

This may be a s illy question but what is an APU on a jet aircraft?

4 replies: All unread, jump to last
 
User currently offlineBig777jet From , joined Dec 1969, posts, RR:
Reply 1, posted (13 years 3 days 18 hours ago) and read 716 times:

APU stands for Auxilury Power Unit. That aircraft has power small engine to keep supply power for electricity and air conditioner or heat while the plane is on the ground. Also, APU must running while take off or landing for in case engine failure and APU is running to re-start engine.

Big777jet



User currently offlineBDDLCW From , joined Dec 1969, posts, RR:
Reply 2, posted (13 years 3 days 12 hours ago) and read 701 times:

Can anyone confirm that the APU is running during takeoff and landing? I know it doesn't have to be, because airliners fly with inop APUs all the time. I thought they were always shut down prior to flight and not restarted until they were back on the ground. I would think that you would want all the fuel going to the engines for flight and if an engine were to fail you could use the still running engine/s to cross-start the failed engine.


User currently offlineSA365C1 From United Kingdom, joined Apr 2001, 131 posts, RR: 0
Reply 3, posted (13 years 3 days 11 hours ago) and read 693 times:

No APU's are not running during take off and landing think about it, the APU is distibuuting power to the aircraft while the engines are not running, when the engines are running the generators are providing power so why would you need the APU?????

User currently onlineSQ325 From Germany, joined Jul 2001, 1451 posts, RR: 7
Reply 4, posted (13 years 3 days 10 hours ago) and read 684 times:

APU is a gas-turbine which provides energie and hydraulic pressure, when the engines are out and the plane is on the ground. APU will be stopped after engine start and be activated at the gate before the engine shutdown. But inflight the Apu is out if you need energie for the restart of a engine
(what i truely doubt, because if an engine is giong to die inflight there is a reason, maybe I try it once but then I'll leave it off) take the energie supply of the other engine(s)


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