vfw614
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Converted 747-400F - The Hump?

Sat Nov 19, 2011 2:49 pm

I am pretty sure that this must have been discussed, but I could not find a thread, so I am asking:

With more and more Boeing 747-400 getting converted into freighters, I am wondering what happens to the rather extensive upper floor area? The factory-fresh -400F have the small hump because an extended upper floor apparently limits the height of the main floor in the forward cabin area. So what happens if a pax -400 is getting converted? Is the floor getting removed? And if so, is the addditional volume ever getting used? If not, is the second floor just empty or is getting used for handloaded small parcels e.g.?
 
PC12Fan
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RE: Converted 747-400F - The Hump?

Sat Nov 19, 2011 2:53 pm

IIRC, about half of the upper deck floor is removed aft of the door. This allows for the 10 foot pallets to fit which obviously wouldn't if the floor was still there. Removing "half" of the floor results in aproximately the same floor space as the standard freighter "hump".
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MD11Engineer
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RE: Converted 747-400F - The Hump?

Sat Nov 19, 2011 2:57 pm

Quoting PC12Fan (Reply 1):
IIRC, about half of the upper deck floor is removed aft of the door. This allows for the 10 foot pallets to fit which obviously wouldn't if the floor was still there. Removing "half" of the floor results in aproximately the same floor space as the standard freighter "hump".

The area aft of the emergency exits has it´s original floor beams removed and new tension members installed higher up in the frames. This, together with extensive redesigning of the airconditioning plumbing housed in this area, allows to have the main cargo deck ceiling raised further forward to almost the upper deck emergency exits.

Jan
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vfw614
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RE: Converted 747-400F - The Hump?

Sat Nov 19, 2011 3:06 pm

So my understanding is that in the hump just hot (or rather cold) air is getting carried around - as no floor exists, it cannot be used for stowage purposes and with beams in the way, nothing can be put on top of the large pallets located on the ground floor?
 
zanl188
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RE: Converted 747-400F - The Hump?

Sat Nov 19, 2011 3:18 pm

Quoting vfw614 (Reply 3):
So my understanding is that in the hump just hot (or rather cold) air is getting carried around - as no floor exists, it cannot be used for stowage purposes and with beams in the way, nothing can be put on top of the large pallets located on the ground floor?

Since the upper deck floor has been removed and its associated beams have been moved up and out of the way pallets on the main deck can be built to their maximum height.

Look closely and you can see the mod in this pix:


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Click here for bigger photo!

Photo © Dirk-Jan Kraan



Check out this thread for additional info:

http://ww.airliners.net/aviation-forums/tech_ops/read.main/306013/

[Edited 2011-11-19 07:24:41]
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MD11Engineer
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RE: Converted 747-400F - The Hump?

Sat Nov 19, 2011 11:37 pm

Quoting vfw614 (Reply 3):
So my understanding is that in the hump just hot (or rather cold) air is getting carried around - as no floor exists, it cannot be used for stowage purposes and with beams in the way, nothing can be put on top of the large pallets located on the ground floor?

I´m on vacations now, but when I´m back at work, I´ll take a picture of the inside of a converted 747-400´s hump. There are some walkways for maintenance (e.g. the actuation bottles for the emergency exit doors are located there, which need to be checked during each daily check at our airline), plus plenty of aircon ducts (e.g. upper deck trim air valves, recirculation fans and filters).


Quoting zanl188 (Reply 4):
Since the upper deck floor has been removed and its associated beams have been moved up and out of the way pallets on the main deck can be built to their maximum height.

With our Jumbos the main deck cargo hold has linings all the way around.

Jan
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RE: Converted 747-400F - The Hump?

Sun Nov 20, 2011 8:20 am

In all converted 747-400's lining is installed (new regulations.), so it's very difficult to show the actual modification details (tension ties etc.) inside the 747-400BCF or 747-400BDSF aircraft. Almost every modification detail is hidden by white panels.
For that reason a 747-300SF shows the required modification far better, because only partial lining is installed.

Note :
All converted 747-100,-200, -200(SUD) and 300 freighters (by Boeing and others) are mentioned "Special Freighter" ( -SF) and are modified according a Supplemental Type Certificate (STC) and/or Boeing Master Change.

To differentiate the( more expensive) Boeing freighter modifications from the "third party" modifications, Boeing invented a new way to name the P-F converted aircraft :

All converted 747-400 aircraft by a Boeing designed modification are called "Boeing Converted Freighter" (-BCF).
In the 747 type certificate this variant is listed as a new 747-sub type.
See page 24/55 : http://www.airweb.faa.gov/Regulatory...070737c/$FILE/A20WE%20Rev%2047.pdf

The 747-400's converted by Bedek Aviation, Israel (third party) are now called "BeDek Special Freighter" (-BDSF) and are operated under a Supplemental Type Certificate (STC).
See : http://www.iai.co.il/sip_storage/FILES/5/34595.jpg
See : http://www.youtube.com/watch?v=0JeDrrOL5gk&feature=player_embedded

[Edited 2011-11-20 00:22:56]
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