Two helis (think one was a Llama) collide head-on but displaced sideways about 20 feet. Both pilots feel the bang and set up last-ditch autos, then realise they still have control and so land safely. If the Llama had been carrying a passenger, he would have been decapitated, according to the hole in the canopy. (Pilot magazine, years and years ago, reported by Stephan Wilkinson).