The USAF initiated the C-X (Cargo X) programme in October 1980; McDonnell
Douglas was selected as prime contractor on 19 August 1981.  The C-X, later
designated C-17, is primarily a C-141 replacement, with some overlap with
the roles of the C-5 and C-130.  The first prototype flew in September
1991.  The programme has suffered many technical and political setbacks,
but production has begun, although the USAF's order has been reduced from
the original 210.  40 have been definitely ordered, of which 10 had been
delivered by February 1994.  A follow-up order for another 80 is on hold,
conditional on MD correcting design flaws and cost overruns; a decision
will be made by the end of 1995.

McDonnell Douglas are considering a civilian airfreight version, under the
designation MD-17.

Vital statistics (C-17A):  length 53.04 m, span 52.20 m, empty weight
122016 kg, max weight 263083 kg, cruise speed 818 km/h, range 8710 km,
payload 78108 kg; power plant:  four 185.50 kN Pratt & Whitney F117-PW-100
turbofans.