justplanenutz
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Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 2:31 pm

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.
 
Dalmd88
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 5:17 pm

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.
 
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HAWK21M
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 7:05 pm

Would it be economically viable?
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MD11Engineer
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 7:14 pm



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
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justplanenutz
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 8:09 pm



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.
 
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TZTriStar500
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 10:36 pm



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.
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Starlionblue
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RE: Retrofitting 737NG W. Flat Bulkhead

Fri Nov 14, 2008 10:55 pm



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." - John Ringo
 
Viscount724
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RE: Retrofitting 737NG W. Flat Bulkhead

Sat Nov 15, 2008 1:39 am



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.)
 
474218
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RE: Retrofitting 737NG W. Flat Bulkhead

Sat Nov 15, 2008 2:09 am

 
justplanenutz
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RE: Retrofitting 737NG W. Flat Bulkhead

Sat Nov 15, 2008 2:10 am

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

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