Since this thread has been resurrected the aircraft that Donald Busch was killed in was previously owned by a gentleman in Sydney who owned a number of properties in NSW and Qld. He also owned two P51s'. The first was sold to Donald Busch and the second to a man in Sydney whose name I forget.
I met a LAME who had been responsible for the maintenance on both aircraft before their sale and he was present when Busch crashed. He estimated the aircraft was about 1,500' AGL in a steep turn when it stalled and flicked into a spin. The original crash comic said it spun 4 times. This man said a P51 would lose a 1,000' a turn in a spin and there was no way it spun 4 times. He attributed the crash to poor handling by pulling too hard in a steep turn causing it to stall. The CG problem mentioned earlier may well have been a contributing factor.
For those who know their aviation stories there is the one about a then DCA F27 being formatted on by a (variously) Spitfire/Mustang/WW2 aircraft in the 1960s'. When asked to identify itself the aircraft pulled up and away through cloud and disappeared. That aircraft was a Mustang and was one of the two owned by the gentleman from Sydney. At the time the aircraft was located on one of his properties in Qld not far from the NT border. This was told to me by the owner standing next to the aircraft that he was in the process of selling.