Re: DC9-15 (was Re: Northwest A319 will replace what ?)

Date:         17 Aug 97 15:41:10 
From:         "Stefano P. Pagiola" <>
References:   1 2 3 4 5 6
Next article
View raw article
  or MIME structure

I wrote:
> when the MD-90 came out, Douglas
> didn't follow their previous scheme.  Now MD-90 is the
> model number and variants of it are indicated by dashed
> numbers, beginning with -30, for long and convoluted
> reasons.

I've been asked by e-mail to explain what those
"long and convoluted reasons" were.  OK, here we go.

When Douglas began thinking of further developments
of the DC-9 Super 80 -- as it was then known --in the
early 1980s, it called the proposed new version the
DC-9 series 90.  This was changed to MD-90 after the
historic "DC" designation was dropped in favor of "MD"
to more closely associate Long Beach products to parent
McDonnell Douglas.  The project to which the "90"
designation was first applied, however, was not a
further stretch but a shrink -- a project that eventually
developed into the MD-87.  A lengthened version of the
MD-80 with V2500 or CFM-56 turbofans was mooted in the
mid-1980s, under the designation MD-89, but it wasn't
pursued very aggressively.  The MD-90 designation was
next used to describe a family of aircraft based on the
MD-80 fuselage and unducted fan engines such as the GE-36
or the Allison 578-DX.  Three versions were proposed: the
114-seat MD-91, 165-seat MD-92, and 180-seat MD-93.  The
failure of fuel prices to rise as rapidly as had been
anticipated led to airline interest waning.  The MD-90
family was then re-proposed in V2500-powered versions as
the MD-91V, -92V, and -93V.

This latest version was launched in October 1989.
Now that "80" or "90" was essentially the model number
rather than a series number, having only one digit to
indicate differences in variants was constraining,
especially when multiple lengths (each of which might
conceivably spawn variants of their own in the future)
were being considered so a new dash number series system
was re-instituted, patterned on the previous DC-9 scheme.
So the three versions on offer were re-designated
MD-90-10 (previously -91V), -30 (ex -92V), and -40 (ex
-93V), respectively, with the -20 designation reserved
for re-engined MD-80s (which would have been
intermediate in length between the -10 and -30).

Delta Airlines' initial order for up to 50 MD-90-30s
launched that variant.  Plans for a family of aircraft
were later dropped (with the MD-95 taking over the role
the MD-90-10 would have filled), but by the MD-90-30
had acquired its -30 suffix.  An MD-90-50 version was
being discussed during 1995; this would have been a
higher gross weight version of the -30, rather than a

All opinions are my own.
Check out my web site (under construction) at