Mart,
At this point in time, there can only be speculation as to the cause of the crash, IMHO.
However, the CarterCopter's web pages and referenced patents provide a lot of information about the intended aerodynamic and flight-control features of this unique craft.
As with other unique rotorcraft, the CarterCopter would make for interesting study, discussion and assumptions, for those who are intrigued by 'the rotor'.
Dave