Apu Limitation On A320
Thread Starter
Joined: Nov 2008
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From: actually in ppruneland.
Apu Limitation On A320
Hi, prunners:
well I have a question and I'm sure someone will help me , why if we have one generator inop and deffered by MEL the flight altitude is limited to 33500ft and the operating limitation of the apu could be up to 39000ft?
thank you
toby320.
well I have a question and I'm sure someone will help me , why if we have one generator inop and deffered by MEL the flight altitude is limited to 33500ft and the operating limitation of the apu could be up to 39000ft?
thank you
toby320.
Joined: Feb 1998
Aviation Qualifications: ATPL
Posts: 1,595
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From: Formerly of Nam
Thats a new one on me.
It might be a Co-imposed limitation. As far as I know the Airbus MMEL states no such lim.
Check with your chief pilot. If so ask him the reason - Id be interested myself.
It might be a Co-imposed limitation. As far as I know the Airbus MMEL states no such lim.
Check with your chief pilot. If so ask him the reason - Id be interested myself.
Joined: Mar 2000
Posts: 1,337
Likes: 1
From: Sunrise Senior Living
If you look at the APU envelope in the 'Limitations', there is no limit on starting the APU unless in the Emerg Elect Config but the 90Kva limit starts at 35000'. Perhaps there's a clue there!
There are, of course, other limits concerning bleed air from the APU.
Cheers
mcdhu
There are, of course, other limits concerning bleed air from the APU.
Cheers
mcdhu
Joined: Oct 2009
Posts: 1,270
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From: UK
Hi Toby320,
Edit.
All our aircraft have that limitation. FL335 ISA + 30 is just about where the maximum APU 100% available generator output starts to fall off.
I can only guess that the regulations specify that, at dispatch, we must plan a FL where 100% APU generator is available (in case the remaining main engine geny failed).
Edit.
All our aircraft have that limitation. FL335 ISA + 30 is just about where the maximum APU 100% available generator output starts to fall off.
I can only guess that the regulations specify that, at dispatch, we must plan a FL where 100% APU generator is available (in case the remaining main engine geny failed).
Last edited by rudderrudderrat; 8th October 2010 at 11:51. Reason: re-read MEL
Thread Starter
Joined: Nov 2008
Posts: 104
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From: actually in ppruneland.
thks for your replies I'm still looking for an answer may be the clue is like rudderruderrat said, sounds logic but let wait for some more reference as soon as I have some answer I will waiting for some more clues
tks
toby320
tks
toby320
Joined: Sep 2010
Posts: 49
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From: FL390
It's in my companies MEL .. (UK airline)
I agree with rudderruderrat,
From APU Envelope info:
30000 @ ISA 100 % (90 KVA)
35000 @ ISA 93 % (84 KVA)
One may be inoperative provided :
6. Flight altitude is limited to 33500 ft, and
6. Flight altitude is limited to 33500 ft, and
From APU Envelope info:
30000 @ ISA 100 % (90 KVA)
35000 @ ISA 93 % (84 KVA)
Last edited by SupaMach; 8th October 2010 at 14:41.
