"Brendan Cowan" wrote in message
...
Isn't that just exhaust staining from the thrust reversers?


Yes it is - the Tornado is fitted two 'buckets' that are shaped like a
quarter segment of orange peel. These rotate over the rear of the engines
to form a semi spherical steel umbrella that re-routes the exhaust through
180 degrees. Only used on landing (obviously) these buckets cover the rear
of the aircraft with carbon deposits as they act like retro rockets to give
a very short landing capability. As an aside, some pilots will blow a wolf
whistle by operating these buckets on taxiing, a very strange sound from an
aircraft.