On Jun 29, 3:40 pm, AES wrote:
Taxiing in on a just landed United flight at LHR a few weeks
ago, I caught a quick glimpse through a window across the
cabin of what looked (to a non-expert) like a semi-derelict
small-sized "Super Guppy" parked off by a big hangar:
fat fuselage, three engines (one huge one up in the tail),
faded bile-green color, what looked like big rust streaks
running around the fuselage.

What might I have been seeing?

I'm pretty sure you saw the fire training mockup. It looks like a
cross between a short 747 and a DC-10 and is painted green. See the
following pictu

http://aviation-safety.net/photos/di...0&vnr=1&kind=F

Eric