LAXDESI
Topic Author
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Twin Aisle Replacement Analysis For B737/757/767

Sun Aug 03, 2008 5:26 am

I have recently come across threads about Thompson seats with staggered seating. In theory, these seats would convert a 7-abreast B767 to 8-abreast Y with staggered seating. Likewise, 8-abreast A332 could become 9-abreast Y. It is my understanding that Delta is converting some of its 767s to 8-abreast staggered with Thompson seats.

If the staggered seats turn out to be acceptable, and become the norm, then Boeing could design its 737 replacement as a twin aisle 7-abreast with staggered seating. I will use B739ER as the base model to carry out the financial case for such a replacement.

Note below cabin dimensions for the 739ER and the 739RS(twin aisle, CFRP, new engines):
739ER 739RS
Fuselage Length 138.16 feet
Cabin Width 11.58 feet 14 feet
No. of single class seats 215 245

The 739RS would only need 14 feet in cabin width to accomodate two aisles with 2-3-2 staggered seating. I hope Keesje will come up with graphics to illustrate this point. The fuselage length of the replacement will remain the same.

Note below a summary of estimated technical specifications for 739ER and 739RS.
OEW 98,495 112,000
MTOW 187,700 204,000
MZFW 149,300 169,000
MSP 50,805 57,000 (Max. Structural Payload)
Range 3,200 3,500 (Max. Design Range in nm)
Wing size 117 ft.(w/winglets) 125 feet
The 739RS can carry its max. payload to 2,900 nm.

For a 2,000 nm mission,
737ER burns 3,877 gallons of fuel, carries 5,655 lbs. cargo, GSM .0090
739RS burns 3,314 gallons of fuel, carries 5,550 lbs. cargo, GSM .0068

739RS saves about $2,200 in fuel costs.
739RS may earn $4,200(30Y seats X 70% LF X $200) more in seat revenue.

The net advantage to 739RS is about $6,400 per trip--about $7 million annually.

If my estimates are fairly accurate, then a twin aisle with two different wings could be utilised to replace both 737/757 and 767 series. The smaller 125 feet wide wing would be on the 738/739/752 replacement, and the larger 160-170 feet wing would be on the 767 replacement.

For the series with the smaller wing, the shortest fuselage length would be 130 feet(current B738 length), and the longest would be 155 feet(current B752 length). The single class seat count would range from 195 to 260, and the range would be around 2,800-3,500 nm.

For the series with the larger wing, the shortest fuselage length would be at 160 feet and the longest would be at 200 feet, providing replacements for 762/763/764. The single class seat count will range from 280 to 400, and the range would be around 5,800-6,800 nm.

Looking forward to your comments/feedback.
 
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larshjort
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RE: Twin Aisle Replacement Analysis For B737/757/767

Sun Aug 03, 2008 8:53 am

What about a 175 feet ~320 seat single class version with the small wing, Would it be possible as a A300-600 replacement? Or would it lack range?

/Lars
139, 306, 319, 320, 321, 332, 34A, AN2, AT4, AT5, AT7, 733, 735, 73G, 738, 739, 146, AR1, BH2, CN1, CR2, DH1, DH3, DH4,
 
roseflyer
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RE: Twin Aisle Replacement Analysis For B737/757/767

Sun Aug 03, 2008 4:48 pm



Quoting Larshjort (Reply 1):
What about a 175 feet ~320 seat single class version with the small wing, Would it be possible as a A300-600 replacement? Or would it lack range?

Isn't that exactly what the 787-3 is trying to do and not selling terribly well at doing either?
If you have never designed an airplane part before, let the real designers do the work!
 
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American 767
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RE: Twin Aisle Replacement Analysis For B737/757/767

Fri Aug 29, 2008 1:07 am



Quoting LAXDESI (Thread starter):
Boeing could design its 737 replacement as a twin aisle 7-abreast with staggered seating.

That's not a feasible solution unless the fuselage cross section diameter becomes at least as large as that of the 767. Because adding one seat per row, means adding one aisle and one seat. You go from a 3-3 layout to a 2-3-2 layout. But if you really want to keep the same cross section as that of the 737, 757 or even the A320, this idea would not work out.

In the case of the 767, you would only add one seat and no additional aisle. 8 seat per row on a 767, that's still realizable because it simply goes from a 2-3-2 layout to a 2-4-2 layout (I believe Britannia from the UK used to do that), you still have the two aisles and you still have every non aisle seat one seat away from an aisle. However, the only negative point about this idea is passengers will feel less comfortable because the seats would be slightly smaller in width.

Ben Soriano
Ben Soriano
 
Viscount724
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RE: Twin Aisle Replacement Analysis For B737/757/767

Fri Aug 29, 2008 3:42 am



Quoting American 767 (Reply 3):
In the case of the 767, you would only add one seat and no additional aisle. 8 seat per row on a 767, that's still realizable because it simply goes from a 2-3-2 layout to a 2-4-2 layout (I believe Britannia from the UK used to do that),

Yes they did. Very cramped and uncomfortable seating.


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keesje
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RE: Twin Aisle Replacement Analysis For B737/757/767

Fri Aug 29, 2008 9:31 pm

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