SM-
It's a fairly complex situation, with regards to seat design and supply.
Seats, as well as a majority of the cabin furnishings and equipment, are
classified as BFE - Buyer Furnished Equipment. That means the
airline/operator decides what seat product he wants to use and buys it from
the seat vendor and either has it shipped to Boeing or Airbus for new build,
or makes arrangements for the new seats to be retrofitted into existing
aircraft.

There are about a half dozen main seat manufacturers in the world, such as
BE Aerospace, Britax, Koyto, Recaro, to name a few. They typically do the
engineering design, testing, certification, and manufacturing to
requirements and aesthetic designs usually determined by the purchasing
airline. There are some standard seats that are offered off the shelf by
seat manufacturers but those are typically only economy or shorthaul seats
and are not often bought my major mainline airlines. Business Class and
First Class seats are almost always bespoke designs done for a specific
airline (good examples are the first class seats of British Airways, Virgin,
Singapore, Emarites, American). The reason for that is that airlines
differentiate between themselves as well as within their own on-board brands
through the on-board product and it's a real race to have the best seat in
the business. And the airlines are very secretive about their development
programs and normally protect the intellectual property rights of their
seats to the hilt.

Boeing and Airbus design the aircraft structure and seat rails to withstand
certain loads up to 16Gs (but I forget the design weight of seat/passenger).
Boeing's real responsibility ends at the seat rail. The seat manufacturer
has to design his attachments and the seat structure so as not to dislodge
or deform up to 16Gs. When an airline specifies new seat or buys one off
the shelf, Boeing will typically have to do a load analysis to ensure that
the seat/rail interface will be up to the job.

Not all seats are certified for all aircraft for two major reasons. One is
layout and specifics of the design. For instance, a first class seat for a
777 will not automatically work in the nose of a 747 because the seat rails
in the nose of the 747 are not parallel to the fuselage, they curve inwards
following the shape of the nose. This means a straight-ahead crash case
would put a slight sideways and twisting load on the structure that the 777
wouldn't. So the same seat would have to be fully tested and certified
seperately for both the 747 and 777. The other reason is related to the
first in that these tests and certification processes are very expensive.
There's not really much incentive to certify a seat for a 777 if you have no
customers who are interested at the moment. The airlines understand that
certification for their specific aircraft type and layout is part of the
deal when buying a bespoke seat. For an off-the-shelf seat, a manufacturer
may get his seat certified in a whole bunch of aircraft to give his product
a wider target market (BE Aerospace's "Spectrum" shorthaul seat is a case in
point).

And finally, it gets more complicated when you look at the aircraft layout
overall. Though they feel it, not all seats are the same, even in economy.
There's the quadruple set in the middle of the 747, for instance, then there
are the triples on the outside, there's the front row which have meal trays
configured differently, quite often an exit row may have a different design
again, crew seats have extra harnesses so are different again, and it can
just go on and on depending on how specialized the layout in the cabin is.
Each variant of the basic design has to be tested and certified.

That's a quick primer on how airline seats are managed. Hope it helps
answer your question.

Shawn



"smjmitchell" wrote in message
u...
Who are are the main manufacturers of airliner seats ?

Do Boeing / Airbus and other airliner manufacturers design and make their
own or are they supplied under contract by companies that specialise in
the
manufacture of seats ?

How much standardization is their in seats ... i.e. are they
interchangable
between aircraft types or does each aircraft type have a special seat
design
?