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chornedsnorkack
28th Feb 2006, 13:11
The talk of the Airbus 380 and Boeing 787 makes me wonder how a good widebody cross-section is chosen.
B747
The first widebody ever was Boeing 747.

Anything before was narrowbody... the biggest had been Boeing 707, which was 376 cm wide outside, 6 seats across and single aisle.

Boeing 747 was 650 cm outside, 610 cm or so inside.

Initially, Boeing 747 used to fly 9 across in Coach, 3-4-2. However, later on 3-4-3 10-abreast seating appeared and has become standard. When and how?

Also, Boeing 747 had a huge attic - mostly empty and useless.

However, just behind the cockpit there was a small upper deck. At first, it was a lounge.

When and how did seats get there?


DC-10
DC-10 was the next widebody. 602 cm outside, something over 570 cm inside width.

I hear that it used to have 2-4-2 8-abreast layout in Coach for quite a long time.

Note that it was less than 40 cm narrower than B-747. In B-747, there is not quite space from 1 extra column with same aisle/seat widths. And there are still 2 aisles - so in 3-4-2 the extra seat is a middle seat over and above being narrower.

Was DC-10 felt to be more spacious than B-747?

Then, somehow, extra seat columns appeared. Some DC-10s fly 9 abreast in 3-4-2 configuration, some are 2-5-2, some are 3-3-3. When did it happen?

And, it is possible to add 10th seat column in 3-4-3. Finnair, which is a legacy, flies their MD-11s 10 abreast now and into future...

Tristar
The third widebody is Lockheed Tristar.

It seems pretty similar to DC-10. Outside width, 597 cm, is just 5 cm narrower than DC-10. Inside width I think still over 570 cm. So, less than 40 cm narrower than Boeing 747.

Tristar started 8 abreast just as DC-10. And Tristar, too, came to seat 9 abreast... and 10-abreast Tristar has also been seen.

Does anyone know just how tolerable is a 10-abreast Tristar?

Also, Tristar made heavy use of underbelly, even though this diminished luggage/cargo space. Lower deck galleys, with lifts and service doors and emergency escapes. And there were lower deck lounges, with integral airstairs (ahead of wing). There was an option of sellable seats on the lower deck - but apart from emergency escapes, this required extra reinforcement of the underbelly in case of a belly landing...

I think DC-10 and Boeing 747 also sometimes have lower deck galleys and airstairs.
Airbus 300
The next (fourth) widebody was Airbus 300.

The Airbus 300 is smaller than either Tristar or DC-10. It is 564 cm wide outside and 528 cm inside. Also, the passenger floor is relatively high, so the plane has a small wasted attic compared to Boeing 747, relatively roomy underbelly and steeply inwards curving sidewalls.

The standard seating is 8 abreast, as on DC-10 and Tristar - and although much less roomy (over 40 cm narrower...) it has lasted longer. 9 abreast has crept in, usually 3-3-3, but does not appear prevalent. I doubt 10 abreast would be possible.

Some Airbuses, like Lufthansa Airbus 340-600, use underbelly for toilets, so it is roomy enough.

Il-86
The next (fifth) widebody was Il-86. It has outside fuselage width 608 cm, so slightly wider than DC-10. Like Tristar, Il-86 makes heavy use of underbelly airstairs.

B-767
The next widebody was Boeing 767. It seems that Boeing had had trouble filling the huge Boeing 747-100, compared to smaller DC-10 and Tristar and had considered making a narrower all-new fuselage desing, but finding it too expensive, shrunk B-747 to get B747SP. However, eventually Boeing did design a new small widebody. B-767 is even smaller than Airbus 300, being 503 cm outside and 472 cm inside width - 56 cm narrower than Airbus 300. So, Boeing 767 normally has 7 abreast with double aisle.
The cross-section is vertically stretched, 541 cm high, so the underbelly height is comparatively large and close to what the bigger widebodies have.

It seems like some airlines can have and have had 8 abreast seats in a Boeing 767...

B-777
The next new widebody was B-777. It is 619 cm wide outside - wider than DC-10 and close to Boeing 747. The inside width is said to be 586 cm - so 24 cm less than Boeing 747.

9 abreast 777 is of course roomier than 10 abreast 747 (since the difference between the widths is less than the width of a seat). However, since there are 10-abreast seats even on Tristars, some airlines have 10 abreast on 777. Not the majority of airlines (yet?).

The cabin difference of 58 cm and 1 extra seat column compared to Airbus 330/340 has dubious valye for passenger comfort - the extra seat cannot be a convenient one. The sidewall slope is much broader on 777, so the width difference on shoulder or eye level is greater... and therefore, a B-777 has a big empty attic.

Future:A380
The first widebody not yet in service is Airbus 380.

The main deck is slightly wider than Boeing 747. Maximum width is 658 cm compared to 610 cm, so 48 cm wider. However, the maximum width is higher, so there is less extra width on floor and armrest level, more on eye level.

The "default" seating is 10 abreast in 3-4-3 - roomier than in a B747.

The upper deck is much wider than the upper deck of B-747 - but it still has steeply sloping sidewalls. As the shape is different, numbers are hard to compare with main decks of other widebodies, but the "default" is 8 abreast in 2-4-2, as on Airbus 300.

Could you have 11 seat columns on Airbus 380?

It could be more cramped than 10 abreast on Boeing 747. But there are planes more cramped than 10 abreast Boeing 747 - like 10 abreast Boeing 777, DC-10 or Tristar. Airbus 380 main deck is about 72 cm wider than Boeing 777, and close to 80 cm wider than DC-10 or Tristar. So, a 11-abreast Airbus 380 seems feasible, and perhaps more comfortable than 10-abreast B-777.

Not sure about upper deck, because of the sidewall slope - can or cannot you have 9 abreast there?

Airbus is to seat 853 people in Airbus 380 on 26th of March. Does anyone know what the seatmap and configuration might be like?
It is said to be 315 seats on upper and 538 on lower deck.

Future:B-787
B-787 is supposed to be begun in June this year - does anyone know the deadline for first flight?

It is said to be 574 cm wide outside. So, 10 cm wider than Airbus 300. But it would be elongated upwards, to have about 600 cm height outside - close to what DC-10 has. Also, it would have thin walls and the floor would be low, so there would be much extra space compared to A-300 - especially at eye level.

How do you think does the width of B-787 compare with Tristar?

Boeing advertised 8 abreast seating on B-787, said to be roomier than A-300. But it has turned out that most customers plan to have 9 abreast!

How comfortable would 9-abreast B-787 be?

And is it possible to have 10 abreast on B-787? It is not that much narrower than Tristar...

Pax Vobiscum
28th Feb 2006, 16:57
Interesting question, chornedsnorkack - I think you've clearly demonstrated that the airlines will continue to cram us in as tight as they can get away with (e.g. 10-abreast on a 777 :ooh:). As has often been stated, most (economy) tickets are bought on price, relatively few customers are even aware that there are differences in configurations between (and, indeed, within) airlines, so there's little incentive for them to do anything else.

My understanding (I don't claim to be an expert, and will firmly deny that I even own an anorak) is that the 747SP is primarily an extended range version of the Classic, the reduced length being incidental to this end. The IL86 is a really nice aircraft from a pax perspective. If memory serves (it's been a while), the config (old Aeroflot single class) was 2-x-2, but I can't remember how many the x was!

CargoOne
28th Feb 2006, 18:23
IL86 is 3-3-3 in economy.

chornedsnorkack
1st Mar 2006, 09:29
Interesting question, chornedsnorkack - I think you've clearly demonstrated that the airlines will continue to cram us in as tight as they can get away with (e.g. 10-abreast on a 777 :ooh:).
And 10 abreast on MD-11. As in Finnair. Which is a legacy, and expanding.

But while 9 abreast in A300 and 8 abreast on B767 have been done, they do not appear prevalent, at least on legacies...

As has often been stated, most (economy) tickets are bought on price, relatively few customers are even aware that there are differences in configurations between (and, indeed, within) airlines, so there's little incentive for them to do anything else.

WHBM
1st Mar 2006, 11:29
It is actually the seat width rather than cabin width which is relevant to an individual pax.

For example the A320 is 6"(15cm) wider than the 737/757, which is normally translated into a 1" wider seat, to the advantage of the pax. However some airlines (Northwest for one) put the same seats in their A320 they do in their 757s. Therefore 6" wider aisle and/or more shoulder-room for the windowseat passenger, but no extra seat width.

The Trident (727-style from the 1960s) had one operator, Channel Airways, who put 7-across seats in it. It just depends how narrow you want to make the seats.

Martinair, Netherlands charter carrier, put an interesting config in their first DC-10s in the 1970s, 3-4.5-2. The 4.5 in the centre section was made with a reduced width "child" seat right in the centre. Didn't experience it but there were pictures in the aviation press at the time. This must have been a nightmare to administer the seating allocations for, does anyone know how they handled it ?

The "some seats are better than others" zealots will also notice that, where tray tables are done armrest-stowed rather than drop-down (eg in row 1) the extra armrest width required is just being removed from the seat width allowed. So bulkhead seats can mean more legroom but less width.

chornedsnorkack
1st Mar 2006, 14:00
It is actually the seat width rather than cabin width which is relevant to an individual pax.
But also seat configuration, and to some extent aisle width. The size of the total cabin affects those, too.

For example the A320 is 6"(15cm) wider than the 737/757, which is normally translated into a 1" wider seat, to the advantage of the pax. However some airlines (Northwest for one) put the same seats in their A320 they do in their 757s. Therefore 6" wider aisle and/or more shoulder-room for the windowseat passenger, but no extra seat width.
Yes, one example.

Quite several airlines have seating blocks, in the 6-abreast narrowbodies, where the middle seat is appreciably wider than the window and aisle seats. Others have all three seats of same width, with the result that passengers do not want to sit in middle seats...


The Trident (727-style from the 1960s) had one operator, Channel Airways, who put 7-across seats in it. It just depends how narrow you want to make the seats.
The current FARs and JARs seem to forbid more than 3 seats from an aisle in any plane having one aisle. Irrespective of the seat width - it seems that 7 across with a single aisle would also be forbidden on A320, or on B767, or even on A380 main deck. This does not seem to depend on pitch, either.
(Wonder if double-decker airliners are subject to that rule if there are aisles on the other deck...)