Re: DC9-MD80

From:         pmc@merit.edu (Philip M. Chuang)
Organization: University of Michigan
Date:         26 Mar 94 00:35:51 PST
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>This may be a very obvious question, but if it is then I would be
>happy with a simple answer!  I recently flew in the exit row on
>a NW flight.  Plastic lettering above the doors indicated that
>the plane was a DC9.  Yet the flight attendants refered to the plane
>as an MD-80 and the seat-back information card was also for MD-80.
>
>Now I am no rocket scientist (just a humble history professor), but
>this would suggest to me that old DC9's were somehow retrofitted
>to become MD-80's (this was certainly an older plane -- soon if not
>already NW will have the oldest fleet of any US carrier, due to all
>its defered and canceled plane orders after the LBO).  Could someone
>tell me precisely how a DC-9 is turned into an MD-80?  Or, if my
>guess about retrofitting is incorrect, could someone explain to me
>the relationship between the two planes?
>
>Thanks in advance.
>
>Ron

This is indeed an obvious question, but with a complicated answer
sure to delight a history professor:
 
(from "Airliners" Winter 1993 issue, a reader noticed that the
 magazine did a story on the final Delta DC-9 flight, but one
 of his references says Delta has 125 DC-9's.  The Editor answers:)


The simple answer is that Delta calls a DC-9-32 a DC-9 and an MD-88
an MD-88. The complex answer revolves around the Type Certificate,
issued in the USA by the Federal Aviation Administration (FAA),
which certifies the airworthiness of a particular type.
This is a data sheet which, acording to the legal wording,
"Prescribes conditions and limitations under which the
product for which the Type Certificate was issued meets the air-
worthyness requirements of the Civil Air Regulations." A Type
Certificate (TC) is issued with the aircraft model designation
exactly as it appears on the manufacturer's application, including
use of hyphens or decimal points, and should match exactly what
is stamped on the aircraft's data or name plate; what the
manufacturer chooses to call an aircraft for marketing or
promotional purposes is therefore irrelevant to the airworthiness
authorities and 'unofficial.'

In the case of the DC-9, the Douglas Aircraft Company (DAC)
received TC No. A6WE for the DC-9-11,-12,-13, and-14 on
November 23, 1965, which was subsequently amended to include
versions up to the -51; in due course, the TC holder became
the McDonnell Douglas Corporation (MDC).  In the case of the
DC-9-81, -82, and -83, DAC applied for and received certification
under these designations as a further amendment to TC A6WE
between August 1980 (DC-9-81) and Octover 1985
(DC-9-83).  In mid-1983, the parent of MDC in St. Louis
threw away 50 years of history and put forth the dictum that 
henceforth the DC-9-80 (Super 80) would be called the MD-80.
However, instead of merely using the MD-prefix as a marketing name,
an application was made to again amend TCA6WE to include the
MD-81, MD-82, and MD-83.  The change was dated March 10, 1986
and a note was made in the TC that although the official designator
remained DC-9-81,-82,-83, the 'MD' designator could be used in
parenthesis, but must be accompanied by the official verion
(ie DC-9-81 (MD-81)).  All aircraft thereafter have MD-81,
MD-82, or MD-83 stamped on the name plate.  Although not
certificated until October 21,1987, DAC had already applied
for models DC-9-87 nad DC-9-87F on February 13, 1985,
and this derivative was similarly officially designated
DC-9-87 (MD-87), althought no name plates were stamped
DC-9-87 (the DC-9-87 F has not been certified)

In the case of the MD-88, an application for a TC model amendment
was made after the above change and therefore there was never
a DC-9-88, only the MD-88 which was certified on
December 10, 1987.  (Interestingly, a proposed MD-88F did not
appear).  Thus any reference to a DC-9-88 is incorrect,
and Delta was correct to say farewell to its DC-9s in
early 1993.
 

Footnotes:
1.  Since Northwest inherited DC-9-82's from Republic,
    "Officially" they do not operate MD-80.
 
2.  The last time I flew on an MD-88 it was on TWA.  The
    pilot told me the plane was assembled by Shanghai
    Aircraft in China, though the Dataplate says Long Beach.
    He also told me that particular plane was an MD-88G
    because it was built with a glass cockpit, can anyone
    help me confirm this?
 
3.  The MD-87 has the Wing, stablizers, engines, and tail
    of MD-88, but with a body almost exactly the length
    of the DC-9-50, but the wings are append further aft
    because the MD-80's engines are larger and heavier
    than that of the DC-9-50.  MD-87 also as an
    extended vertical fin.