KNZ. I'm not saying it was CFITW, just that it has not yet been ruled out with the info we have. A manually flown approach, wx on minima, decide to slow down so reduce collective, nose up a bit, get distracted, next time you look the aircraft is doing 20kts with high ROD that you can't manage to arrest before the surface. Something like that. Even though it sounds unlikely, unfortunately these things do happen, look at the LAX accident recently. All that is pure speculation obviously.
The report mentions 2 miles (not 3) and they would (should) be at 710' at 2 miles on the lLS DME but its a non-precision approach so could be higher or lower.
Bondu - true!