The speculating is terrific, but often self defeating. We "learn" what happened before we know what happened, then we carry that "knowledge" around as truth while the real cause is announced weeks later, and we ignore it.
Some facts:
It was not settling with power. The rate of descent needed to get into vortex ring state is over 2500 fpm for a Hawk, and I saw nowhere near that on the tape. See RW-1's page for an explanation:
http://www.dynamicflight.com/aerodyn...ettling_power/
It was not LTE. A Black Hawk can hover in a 45 knot wind at 10,000 feet DA. The tail rotor is notoriously good, unlike many light helos and Bells.
It could have been a bunch of things, from failures of engines or systems, to loss of reference to simply "over-pitching" or running out of power.
In fact, the coning we see could be from a drop in rpm, and if great enough, it could get the tail rotor on the stops (not LTE, because the rpm drop is the cause). The gentle right turn is consistant with that rpm loss scenario, and the aircraft could start settling against the slope, set off the pilot's personal anxiety alarm bells (thus the cyclic wiggling) and then the main blades hit the slope and that was all she wrote.
One thing, that intact fuselage when the dust settled shows a safe machine, which held its shape and protected its occupants. In a Huey, the transmission would have unplugged and landed in the laps of the pax to help stir things up. Says a lot about US Military crash requirements.