I have some experience of crash investigations, helicopter engineering and statistics.
Let me shed some light in response to previous comments on the TR:
@ The pdf file below has a blown-up section of an image at the crash site (I can't yet post images directly). It clearly shows that:
@The TR was complete and attached at impact.
@ One blade was burnt by the fire after impact and appears to be broken in 2, with the outer portion lying on the boom just below the remaining portion..
@ One blade had damage to its tip.
@ IMO the lack of damage to the blades suggests the TR was turning very slowly or not at all on impact.
@ IMO the damage to the blade at the right bottom corner of the image almost certainly occured on impact with the ground.
@ IMO the damage to the burnt blade is consistent with the rotor not turning on impact and the blade fracturing, possibly helped to fall off by the post-crash fire.
On a final note, that a TR failure is a rare occurrence is essentially irrelevant to assessing whether it occured here or not. Even if it is a 100 million to one chance of occurring, it will occur to someone; we are not looking at the other 99,999,999 flights where it didn't occur.