Slightly digressing from the thread a moment, Shortstripper mentioned John "PeeWee" Judge's accident. It was at Farnborough, but I can't remember the year.
It was the first airshow I had been able to persuade my wife to go to, in an effort to win her over to "Aren't aeroplanes brill?".
PeeWee gave a spirited display, and came from the western end of the airfield, at about 30ft. or so as I recall, rising and decending fairly rapidly as he flew along.
Unfortunately, the rotor hit the top of the tail fin with the tragic results we all know. It happened directly in front of us, and could not have been more graphic. R.I.P.