I was wondering how long this one would stay silent.....I saw the smoke from it when it happened on Tuesday. (Yes I am actually home for a week or two...).
Rumor and speculations:
Observation # 1.
Looking at the tail boom, it appears that the metal skin is bent outwards. Taken at face value, this "could" mean that the separation chain began by the TR drive shaft failing and tearing the skin from the inside, as opposed to being cut from the outside by the main rotor blade. Although the MR blade does show evidence of striking something.
Observation # 2.
It has been "suggested", (pure rumor at this point), that the main transmission gearbox is still attached to the aircraft. This was not the case in the low-G accidents I was associated with back in the 90's, thereby leaning more credibility to #1.