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Retrofitting 737NG W. Flat Bulkhead  
User currently offlineJustPlaneNutz From United States of America, joined Feb 2006, 525 posts, RR: 1
Posted (5 years 10 months 1 week 3 hours ago) and read 2105 times:

Someone can probably answer this quickly, but would it be feasible to retrofit the flat bulkhead used on the 739-ER to ships produced with the curved one? I suspect the answer is that it would mean cutting the plane in half, but perhaps someone here can give a more technical reason.

I thinking 2 things--CO w. a mixed fleet of 739s and the ability to get a 73G to its 149 pax limit.

9 replies: All unread, jump to last
 
User currently offlineDALMD88 From United States of America, joined Jul 2000, 2554 posts, RR: 14
Reply 1, posted (5 years 10 months 1 week ago) and read 2075 times:

I never knew the 739 had a flat bulkhead. I can't figure out why. The traditional curved structure is very efficient from a weight stand point. The curve can withstand more pressure while being thinner than a flat one.

So your question is can they be switched? Yes, If you had the money to burn I'll bet it can be done. Just like on the NatGeo show with the 767. Remove the tail and then seperate the non pressurized 48 section. I'm sure there are some structral mods that would have to be done since the bulkhead is different. And then there would be the ton of paperwork that would have to be done to get approval from Boeing and the FAA.

Now why would you want to go to all that trouble? You would actually lose space in the cabin. The bulkhead would mount to the same spot on the fuselage skin. Now the galley has to be changed. It currently uses some of that space in the center.


User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 2, posted (5 years 10 months 6 days 23 hours ago) and read 2046 times:

Would it be economically viable?
regds
MEL.



Think of the brighter side!
User currently offlineMD11Engineer From Germany, joined Oct 2003, 14026 posts, RR: 62
Reply 3, posted (5 years 10 months 6 days 23 hours ago) and read 2041 times:



Quoting DALMD88 (Reply 1):
I never knew the 739 had a flat bulkhead. I can't figure out why. The traditional curved structure is very efficient from a weight stand point. The curve can withstand more pressure while being thinner than a flat one.

So your question is can they be switched? Yes, If you had the money to burn I'll bet it can be done. Just like on the NatGeo show with the 767. Remove the tail and then seperate the non pressurized 48 section. I'm sure there are some structral mods that would have to be done since the bulkhead is different. And then there would be the ton of paperwork that would have to be done to get approval from Boeing and the FAA.

Now why would you want to go to all that trouble? You would actually lose space in the cabin. The bulkhead would mount to the same spot on the fuselage skin. Now the galley has to be changed. It currently uses some of that space in the center.

Our newer B737-800 have flat pressure bulkheads as well. I assume that they are easier to manufacture and to repair, since they don't contain any 3d curves. BTW, these aircraft use the same galleys as the older ones with the curved pressure bulkhead.

Jan


User currently offlineJustPlaneNutz From United States of America, joined Feb 2006, 525 posts, RR: 1
Reply 4, posted (5 years 10 months 6 days 22 hours ago) and read 2018 times:



Quoting DALMD88 (Reply 1):
Now why would you want to go to all that trouble? You would actually lose space in the cabin. The bulkhead would mount to the same spot on the fuselage skin. Now the galley has to be changed. It currently uses some of that space in the center.

I should have been clearer in my question. Only the 739-ER (not the 739) has the flat bulkhead and it added 2 rows of seats. I believe the reason was to increase capacity to be more competitive with the 321. That also required an additional overwing exit.

The reason I asked the question is because AS and CO now have small subfleets with 12 less pax. Standiization would be useful. The other reason I ask is because the 73G at 149 pax (single class) would be a darn efficient plane.


User currently offlineTZTriStar500 From United States of America, joined Jan 2004, 1452 posts, RR: 8
Reply 5, posted (5 years 10 months 6 days 19 hours ago) and read 1962 times:



Quoting JustPlaneNutz (Reply 4):
The reason I asked the question is because AS and CO now have small subfleets with 12 less pax. Standiization would be useful. The other reason I ask is because the 73G at 149 pax (single class) would be a darn efficient plane.

The existing 73G (w/ dome pressure bulkhead) can already be reconfigured to 149 pax with 2 galleys, 2 lavs and 30" pitch. It is already TC'd at a max 149 pax and does not require a flat pressure bulkhead. The 149 pax max is determined by the fuselage size and number of exits and distance between them for evacuation.

If a 73G had a flat pressure bulkhead, this would not allow any more seats without additional exits so there would be no point. Also, such a mod would be far more expensive than economically justified involving de-mating of the tail section, redesign of the structural interface, and extensive re-certification either as an STC or amended TC.



35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17039 posts, RR: 66
Reply 6, posted (5 years 10 months 6 days 19 hours ago) and read 1954 times:



Quoting DALMD88 (Reply 1):
I never knew the 739 had a flat bulkhead. I can't figure out why. The traditional curved structure is very efficient from a weight stand point. The curve can withstand more pressure while being thinner than a flat one.

The reason for the flat bulkhead is extra capacity:

Quoting JustPlaneNutz (Reply 4):
Only the 739-ER (not the 739) has the flat bulkhead and it added 2 rows of seats. I believe the reason was to increase capacity to be more competitive with the 321. That also required an additional overwing exit.




"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineViscount724 From Switzerland, joined Oct 2006, 25300 posts, RR: 22
Reply 7, posted (5 years 10 months 6 days 16 hours ago) and read 1909 times:



Quoting TZTriStar500 (Reply 5):
The existing 73G (w/ dome pressure bulkhead) can already be reconfigured to 149 pax with 2 galleys, 2 lavs and 30" pitch.

EasyJet 73Gs have always had 149 seats. (They're gradually being replaced with A319s.)


User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 8, posted (5 years 10 months 6 days 16 hours ago) and read 1898 times:

You can read all about it at:

http://www.boeing.com/commercial/737...edia_kit/pdf/900XMediaOverview.pdf


User currently offlineJustPlaneNutz From United States of America, joined Feb 2006, 525 posts, RR: 1
Reply 9, posted (5 years 10 months 6 days 16 hours ago) and read 1896 times:

However, a certain carrier configures their 73g's @ 137 pax, and thus the change would yield 149.

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