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HAWK21M
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B752 APU Gen U/s

Fri May 19, 2006 6:26 pm

On a B752 If the APU Generator is u/s.
Can the APU be run with the Generator Installed.
Or does the APU gen have to be removed to avoid damage to the rotating Gen & blanked to enable the Gen Scavenge pump to function.
Anyone done it practically.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
dl757md
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RE: B752 APU Gen U/s

Fri May 19, 2006 8:39 pm

The MEL says nothing about removing the APU gen when it is INOP. So I'd have to say you can fly with it.

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Buzz
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RE: B752 APU Gen U/s

Fri May 19, 2006 9:04 pm

Hi Hawk21M, Buzz here. No problems with running the APU if the generator has gone bad, as long as it keeps oil inside. It's an oil cooled generator.
Sometimes we get 757's where the APU pneumatics have failed, or generator has failed. SO we use what it'll supply, if there's no physical damage: if it'll supply air... then we don't need the Huffer for an engine start. If the pneumatics have failed, but the electricity is good - that's one less thing to trip over at departure time.
Tonight we had an Airbus through-trip, APU was dead and it would not accept external power. The advice we were given was to trip the generator on the left engine (which was running to supply power) and re-boot the GPCU circuit breakers. After a minute the airplane recognized that external power ws plugged in and life was back to normal.
g'nite
 
fr8mech
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RE: B752 APU Gen U/s

Fri May 19, 2006 9:14 pm

Hey Buzz,

We've had the same problem on our 'Buses. Except everytime I've seen it, we were trying to power from a dead airplane. Batteries on, generator switches off, GPU on, 1 generator switch at a time, repeat as required while throwing choice words at the Eurotrash.
When seconds count...the police are minutes away.
 
LMP737
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RE: B752 APU Gen U/s

Sat May 20, 2006 12:24 am

MEL 24-2 states as long as it's not going on an ETOPS flight longer than 120 minutes the APU gen can be inop.
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HAWK21M
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RE: B752 APU Gen U/s

Sun May 21, 2006 7:03 pm

Quoting Buzz (Reply 2):
No problems with running the APU if the generator has gone bad, as long as it keeps oil inside. It's an oil cooled generator.

What in case The Gen Scavenge filter is clogged leading to Shutdown.Any solution for at Outstation base apart from CF.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
fr8mech
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RE: B752 APU Gen U/s

Sun May 21, 2006 10:18 pm

Quoting HAWK21M (Reply 5):
Any solution for at Outstation base apart from CF.

Not sure what 'CF' is, but if your APU is shutting down, you defer it and move along.
When seconds count...the police are minutes away.
 
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HAWK21M
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RE: B752 APU Gen U/s

Mon May 22, 2006 1:55 pm

Quoting Fr8Mech (Reply 6):
Not sure what 'CF' is

CF or c/f = carried forward [Deffered].
At a Transit Stn if APU pneumatics are Available & B752 at High temp would else need Min Two Ideal Three Ground connections for start [RB211 Engines].
If APU can be run without deffering under MEL would be beneficial by not using Electricals.
But can a damaged Generator be destroyed if it is permitted to rotate.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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