I was addressing a main rotor separation mostly in the context of what others have suggested, I personally think that is an unlikely scenario. But other than being a professional physicist, a greenhorn helicopter pilot, but seasoned fixed wing pilot having flown many different types from small to heavy (and corresponding professional level human factors involvement), I have little experience to contribute other than the physics behind this, and the (likely) human factors involved. The V/S rate deduced from the data points would indicate that main rotor separation remains a possibility though, but there are many ways to make an intact helicopter descend at a corresponding V/S in a more or less controlled state of flight. I have no idea what the site evidence says other than a news article stating the main body of the helicopter was found floating with the tail sticking out of the water.
Are there any non-Robinson aircraft included in your list of main rotor separations that resulted in sheared off tails?
Last edited by physicus; 15th Sep 2019 at 12:22.