imiakhtar
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What is this part on the tail?

Sun Jun 29, 2008 11:53 pm

Hi. I was spotting today at BHX when I saw this thing protruding just aft of the rudder on a PK 77L (AP-BGL)

Big version: Width: 448 Height: 336 File size: 16kb


From another angle, during engine start

Big version: Width: 448 Height: 336 File size: 18kb


I saw that it was extended during the taxi for takeoff, but couldn't tell whether it was still sticking out during take. Apologies for the poor quality pics. Does anyone know what it is?

Thanks  Smile
Whatever happened to Leon Trotsky?
 
brendows
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What is this part on the tail?

Sun Jun 29, 2008 11:57 pm



Quoting Imiakhtar (Thread starter):
Does anyone know what it is?

This is the APU (auxiliary power unit) intake door, in its open position. The door is closed when the APU is off (for example when the 777 gets power from the generators in the engines.)
 
474218
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What is this part on the tail?

Sun Jun 29, 2008 11:58 pm



Quoting Imiakhtar (Thread starter):
Does anyone know what it is?

APU inlet.
 
imiakhtar
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What is this part on the tail?

Mon Jun 30, 2008 12:21 am



Quoting Brendows (Reply 1):
This is the APU (auxiliary power unit) intake door, in its open position. The door is closed when the APU is off (for example when the 777 gets power from the generators in the engines.)



Quoting 474218 (Reply 2):
APU inlet.

I should have realised it had something to do with the APU considering the close proximity to the APU exhaust. Thanks for the prompt replies  Smile .

Regards
Imi
Whatever happened to Leon Trotsky?
 
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HAWK21M
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 5:43 am

APU Inlet.
Very similiar to the B757,however its more forward mounted on the type.
How is the routing on the pic like,as it seems far aft.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
tdscanuck
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 6:13 am



Quoting HAWK21M (Reply 4):
How is the routing on the pic like,as it seems far aft.

I believe the air duct runs straight into the side of the APU. The load compressor and generators are probably forward of the air inlet.

Tom.
 
AA737-823
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 11:11 am



Quoting Tdscanuck (Reply 5):
The load compressor and generators are probably forward of the air inlet.

Indeed.
The load compressor and accessory section are forward, while the combustion compressor is aft of the air inlet, which does, as someone mentioned, go directly into the side of the APU plenum.
 
UAL747
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 12:18 pm

Stupid question, but is the APU the thing that makes the high pitched swoooshing noise when the aircraft is at the gate?

UAL
"Bangkok Tower, United 890 Heavy. Bangkok Tower, United 890 Heavy.....Okay, fine, we'll just turn 190 and Visual Our Way
 
boeing767mech
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 12:24 pm



Quoting UAL747 (Reply 7):
Stupid question, but is the APU the thing that makes the high pitched swoooshing noise when the aircraft is at the gate?

That's the one, some people would joke and say it turns air and fuel into noise. Since on a hot day some of our APU's have problems cooling the cabin.

David
Never under-estimate the predictably of stupidty
 
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HAWK21M
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RE: What Is This Part On The Tail?

Mon Jun 30, 2008 12:54 pm



Quoting Tdscanuck (Reply 5):



Quoting AA737-823 (Reply 6):

Thanks.
Do you have a pictoral view of the routing?

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
tdscanuck
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RE: What Is This Part On The Tail?

Tue Jul 01, 2008 4:50 am



Quoting HAWK21M (Reply 9):
Do you have a pictoral view of the routing?

I've hunted around the web quite a bit and haven't found a good one of the 777 yet. It's in section 1 of the AMM, but I can't post that here.

You can get a rough idea of how its' done from here:
http://www.b737.org.uk/apu.htm

About 1/4 of the way down the page is a labelled picture lookup up at the 737 APU from below. Just aft (to the right) of the oil tank you can see a flat metal band that appears to wrap all the way around the APU...that's the inlet plenum. It's a radial inlet. The inlet duct hooks on to the plenum about 180 degrees around the APU from what you can see here. The duct basically runs straight from the side of the APU to the side of the airplane. The 777 is similar, only the duct goes almost straight up to the inlet beside the vertical stab. As you can tell, about half of the APU is ahead of the inlet.

Tom.
 
AA737-823
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RE: What Is This Part On The Tail?

Tue Jul 01, 2008 8:58 am



Quoting HAWK21M (Reply 9):
Thanks.
Do you have a pictoral view of the routing?

I do NOT... isn't that a SHAME????
I have some training stuff from Alteon, but it's proprietary, so I'm not inclined to post it on the Net.

The picture in the link is of a classic 737 APU. This design doesn't have a separated load compressor at all... only the 737NG, 744, and 777 have that design. I don't even know whether the 75/67 do.
 
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HAWK21M
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RE: What Is This Part On The Tail?

Tue Jul 01, 2008 9:05 am



Quoting AA737-823 (Reply 11):
I have some training stuff from Alteon, but it's proprietary, so I'm not inclined to post it on the Net.

I understand.

Quoting Tdscanuck (Reply 10):
I've hunted around the web quite a bit and haven't found a good one of the 777 yet. It's in section 1 of the AMM, but I can't post that here.

Any page reference,I could check the AMM with friends at AI & 9W.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
tdscanuck
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RE: What Is This Part On The Tail?

Wed Jul 02, 2008 12:26 am



Quoting HAWK21M (Reply 12):

Quoting Tdscanuck (Reply 10):
I've hunted around the web quite a bit and haven't found a good one of the 777 yet. It's in section 1 of the AMM, but I can't post that here.

Any page reference,I could check the AMM with friends at AI & 9W.

777 AMM Section 1, 49-00-00, Page 3 & 11

Tom.
 
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HAWK21M
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RE: What Is This Part On The Tail?

Wed Jul 02, 2008 8:55 am



Quoting Tdscanuck (Reply 13):
777 AMM Section 1, 49-00-00, Page 3 & 11

Thanks.tom.
regds
MEL
I may not win often, but I damn well never lose!!! ;)

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