Just one to throw into the ring for discussion as the idea of the rotors coming to a stop has me thinking more on the transmission. Loss of fuel, he could auto rotate although at the height he was at i believe it would not be achievable. I vaguely remember an incident on the Lynx freewheel actuator that caused loss of drive but if memory serves this would result in a twist on the intermediate drive shafts of which at first pass isn't shown on the pictures ? Thoughts…
Helicopter Crashes Caused by Freewheel Disengagements