Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
User currently offlineBACONCORDE From United States of America, joined May 2000, 100 posts, RR: 0
Posted (14 years 10 months 1 week 1 day 2 hours ago) and read 912 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 (14 years 10 months 1 week 1 day ago) and read 881 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.


User currently offlineBDDLCW From , joined Dec 1969, posts, RR:
Reply 2, posted (14 years 10 months 1 week 18 hours ago) and read 866 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 (14 years 10 months 1 week 16 hours ago) and read 858 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 offlineSQ325 From Germany, joined Jul 2001, 1473 posts, RR: 7
Reply 4, posted (14 years 10 months 1 week 16 hours ago) and read 849 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)

Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
AA Gound Air/APU Cooling Policy? posted Sat Jul 7 2007 03:15:15 by MD88Captain
Aircraft APU Fire @ YVR posted Mon Mar 19 2007 23:10:21 by Flyboy2001
747LCF APU Air Delivery posted Thu Nov 23 2006 00:40:58 by B737700doctor
747LCF Has No APU? posted Mon Oct 9 2006 02:23:41 by Kaitak744
Pictures Of APU. posted Tue May 9 2006 12:34:23 by Qslinger
Running Without APU - For 2 Weeks? posted Mon Jan 16 2006 21:02:20 by Halophila
A343 Vs. A346 Apu Exhaust posted Tue Nov 8 2005 16:54:55 by MGASJO
DC9/MD80/MD90/717 APU posted Mon Nov 7 2005 05:50:12 by BR715-A1-30
APU Exhaust On DC-9/MD80/B717 posted Tue May 10 2005 03:44:00 by 4holer26
BAE 146 APU posted Mon Jan 31 2005 10:34:06 by HAWK21M