Looks for me like the attempt to do an autorotation. A vertical impact without any airspeed, low rotor speed and without any turning on a field. Airframe vertical collapse. No debris wide distributed around. Fenestron, tail boom and airframe in a direct line. Flat skids but still attached to the frame. No slip marks on ground. Pilot was able to control the a/c at least in bank and direction. But wasn't able to break the rate of descent on the last meters.
May be the known Rad Alt failure due to the shed bus problem without generators after the loss or the switch off of the engines. Can't see good chances to open the very unfortunately placed shed bus switch in pitch black night and dark cockpit while wearing NVGs autorotating from a few hundred feets. Additionally the 2D view through the NVGs.
But thats the final stage of this accident, there must be something before.
Last edited by tecpilot; 27th Feb 2016 at 12:42.