[Anonymous]

[AMcWhirter]

Interesting piece on flightglobal.com which reveals that Boeing has to revise the maximum range of its planes.

Why ? Simply because over the years, passengers and their luggage have become heavier and so too are the seats they occupy.

The increased seat weight is seen chiefly in the premium cabins where the accommodation has become ever more elaborate.

At the same time, when some airlines have replaced first class they have used the space to install business and premium economy seating which, overall, weighs more than the previous first class seats.

http://www.flightglobal.com/news/articles/boeing-revises-quotobsoletequot-performance-assumptions-415293/

[peter19]

Interesting topic Alex I’m surprised how much some have actually changed in the corresponding distances especially on the 777.

I presume the airlines produce separate figures based on cabin layout in each of their classes and the design of the plane?

[AMcWhirter]

peter19 – Thank you for your comments. This information is of prime importance to those carriers planning long flights and especially the really long sectors.

For example, SIA wants to restart its non-stop flights to N America and has approached both Boeing and Airbus for suitable aircraft. It seems that, for SIA’s purposes, the A350 has the edge on the B787.

Yes the airlines will have their own performance indicators which they may not wish to make public.

[Str8Talking]

This seems to give the 747-800 quite the advantage, all of a sudden! Surely they’re still not trying to market the aircraft in its current form?!

[BigDog.]

Methinks swapping light weight titanium for far cheaper aluminium will also play a part wrt 787s

http://www.telegraph.co.uk/finance/newsbysector/transport/11761286/Boeing-makes-planes-heavier-to-save-money.html

Could be short termist behaviour as over the life of the aircraft, the extra fuel cost incurred carrying weightier aluminium may exceed the down grade material saving, not to mention adverse green impact.

[AnthonyDunn]

Bearing in mind that the weight /performance parameters were first developed some decades ago, since which time we’ve had an epidemic of obesity and the “beached whale” syndrome (most notably in north America), I am altogether surprised that it has taken this long. It cannot just be the advent of fancier business seating that has forced Boeing’s hand on this.

[AMcWhirter]

Fair point, Anthony.

In fact, Boeing has been aware of the larger and heavier human size for decades.

In the 1960s, the designers of the B747 specifically provided a spacious cabin (in economy class) with 9-across seating to accommodate the typical passengers of that era (who were already heavier and larger than those of the 1930s).

This is all revealed in Clive Irving’s book “Wide Body” which was published over 20 years ago.

Since then, of course, the airlines went against Boeing’s advice (just as they have done with the B777/B787) and added an extra seat per row.

So all B747s feature 10-across seating in economy, virtually all B787s are 9-across (rather than 9) and a growing number of carriers have adopted 10-across (rather than 9) for the B777.

[AMcWhirter]

Correction: Re the B787, I should have said 9 rather than 8-across (the latter figure being Boeing’s original recommendation).

[MrMichael]

I see another recent case of people suing for discomfort when being sat next to a weighty heffer in tight seating. The Airlines bang on about size of luggage problem, they also need to do something about the size of the pax trying to squeeze in to a seat where they spill over in to others “bought” space. They should get rid of the seatbelt extenders for free, and make people that need them have to purchase two seats. They would make money out of it, prevent this uncomfortable torture and make the whole travel experience fairer.

[jjlasne]

Also more seats so more weight.

[jjlasne]

Have you ever seen the US documentary on Southwest Airlines at Hobby airport (based on a British TV series of the same) where ground staff examine a passenger from a distance and decide he/she must buy another seat?

[MrMichael]

At the RoseBowl Just outside Southampton they have turnstiles to get in, you scan the ticket and it lets you through. I heard a rumour, if you did not fit through the turnstile you would not fit in the seat…..so you could not get to your seat. Such people were directed to the ticket office and a non turnstile entrance where extra large or two seats would be sold to you (space permitting). For those unfamiliar with The Rose Bowl it is the home of Hampshire Cricket and no better place to spend a sunny afternoon on earth…..except possibly Lords during an Ashes match.

[FDOS_UK]

Interesting article.

Aircraft range is a bit of a red herring, although quoted for marketing purposes.

An aircraft cannot, by definition, have a ‘range.’ What is has is an endurance (measured in time) at a certain engine setting.

The range will then depend on the atmospheric conditions, e.g. if the aircraft flies at 550mph for one hour in calm conditions, it will cover 550 miles, but introduce a tailwind or headwind component of 50 mph and it will cover either 600 or 500 miles.

Then the loading of the aircraft will affect the power setting required, as will the cruising altitude and the profile to get up to it.

So what Boeing is doing, is producing a set of assumptions of how the aircraft may be loaded and operated and is then quoting a ‘range’ of how many miles the aircraft will cover.

They are saying the assumptions have been updated given the trend towards different seats and seating layouts, so presumably they have a standard cargo factor in their assumptions and have left that the same.

Having flown a few hours in smaller aircraft, part of the duties are to compute the weight and balance before departure and one realises that there are quite a set of variables that determine how far you can fly on a given day. You can trade fuel verses pax/luggage weight (so long as the aircraft stays in the balance envelope.)

This is what Boeing’s new assumptions are doing – increasing the weight of pax/luggage/seating etc. mandates a decrease in fuel load and therefore = less endurance (and range.)

Although I’ve never flown an airliner, I believe that constraints are similar (but scaled up) and there is always a compromise – would love to hear a more informed comment from an ailrine pilot.

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