I remember a story that my old man told me a few years ago, can't remember any specifics though except that he would have been there in the late 70's early 80's I think(!) - BOAC you may know better than me actually.
Apparently a Harrier had got bogged down in the beach/runway and the pilot, against the SOPs(?) then selected the nozzles down and tried to lift out of the muck. This, as you can imagine, filled the engine up with lots of beach/runway non-lubricating stuff.
Might have something to do with. Sorry for sticking me nose in.