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Converted 747-400F - The Hump?  
User currently offlinevfw614 From Germany, joined Dec 2001, 4003 posts, RR: 5
Posted (2 years 10 months 6 days 8 hours ago) and read 3714 times:

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.?

6 replies: All unread, jump to last
 
User currently offlinePC12Fan From United States of America, joined Jan 2007, 2444 posts, RR: 5
Reply 1, posted (2 years 10 months 6 days 8 hours ago) and read 3698 times:

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".


Just when I think you've said the stupidest thing ever, you keep talkin'!
User currently offlineMD11Engineer From Germany, joined Oct 2003, 14026 posts, RR: 62
Reply 2, posted (2 years 10 months 6 days 8 hours ago) and read 3674 times:

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


User currently offlinevfw614 From Germany, joined Dec 2001, 4003 posts, RR: 5
Reply 3, posted (2 years 10 months 6 days 7 hours ago) and read 3601 times:

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?

User currently offlinezanl188 From United States of America, joined Oct 2006, 3525 posts, RR: 0
Reply 4, posted (2 years 10 months 6 days 7 hours ago) and read 3595 times:
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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:


View Large View Medium
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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User currently offlineMD11Engineer From Germany, joined Oct 2003, 14026 posts, RR: 62
Reply 5, posted (2 years 10 months 5 days 23 hours ago) and read 3370 times:

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


User currently offline747classic From Netherlands, joined Aug 2009, 2141 posts, RR: 14
Reply 6, posted (2 years 10 months 5 days 14 hours ago) and read 3196 times:

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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