Re: What's in a model number? (MD-95 Structural Specs)

From:         Don Stokes <>
Organization: Victoria University of Wellington
Date:         21 Nov 95 01:19:27 
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  or MIME structure writes:
>I'm not sure I'd use Boeing as a paragon of logic in model numbers, at
>least not at too fine a level, and considering engines in particular
>can get to be a bit silly.  Consider the following:

I don't have much of a problem with the Boeing numbering.  As I understand
it, a 757-222 is:

	Model:	757	Specifies engine size, number of engines,
			gross airframe configuration
	Series:	200	Specifies major variations from basic model in
			range, length, finer airframe configuration
		 22	Specifies airline-specific configuration, engines
			(type within range specified for model/series)
			cabin configuration etc (is there a name for this
			part of the number?).

The model & series numbers are defined by the manufacturer, the rest is
between the airlines & Boeing -- Boeing wouldn't sell a 757-222 to Delta;
maybe the -232 is very similar, but there are differences to suit Delta's
operation over United's.

I haven't followed Airbus as closely, but it seems to me that an Airbus
model number (eg A320) pretty much follows the same function as the Boeing
model.  What happens below that I'm not really sure.

On the other hand, MDD doesn't seem to have released a new "model" since
the DC-10 -- the MD-11 is the same general configuration as the -10;
compare the 747-300 with the 747-400.  The MD-80, -90 & -95 are all
variations of the DC-9 in the same way as a 737-700 is a variation of
the -200.

>I don't quite understand your comment "there isn't any comonality in
>engine configuration between models" with regard to Boeing.  If you
>mean different series within a type, the 737-300, -400, and -500, all
>of which can use the same CFM56-3C1 engine (amongst other variants)

I get the term "model" from Boeing's own literature -- the 737-300 and
737-400 are different series within the same model.

Don Stokes, Network Manager, Victoria University of Wellington, New Zealand. +64 4 495-5052 Fax+64 4 471-5386