Not vortex ring
Personally I think its unlikely to be vortex ring.
To get VRS you have to be going very slowly in both axes, at a stable air speed less than 10 kts, and then it takes a little while to develop. SPs are pretty resistant to VRS. The hypothetical scenario proposed doesn't require VRS to cause the heli to hit the sea.
Yes, I am aware of at least one other event where this happened, not on this continent. They got away with it by the skin of their teeth.
Last edited by HeliComparator; 29th Aug 2013 at 14:06.