The loss of any aircraft is of concern and we will know soon what caused this one. The mindless speculation is fun to read, but it would be nice if we could up the IQ.
It obviously not the transmission shaft as at least in the short term this only results in the loss of the oil pumps. Therefore, not something catastrophic which happens in seconds.
Dual engine failure also would not happen instantly unless it was an uncontained failure of one taking out the other. As there was no bang this obviously did not happen, and this applies to all other major drive system failures.
This could have simply been a missing cotter pin or loose nut in the collective control which resulted in the loss of connection. Once the simplex collective link is broken you are at the mercy of where the blades feather to. Unfortunately at low speeds this may end up with too little lift to do anything but barely cushion the impact.
The Sultan