A pretty dramatic video here of an AStar or TwinStar, I can't tell which, going into the drink. It's not good to jump to conclusions from looking at a video, but it sure looks as if this pilot was not in control of this helicopter. That four people survived this crash says a great deal about the toughness of the airframe!
I have 1100 hours in the AStar 350D (Ecureuil), and for the most part enjoyed flying that machine. But they sure seem to be having a rash of hydraulic systems failures in recent times.
The second video happened longer ago than I thought- 4May 2004.
If you are interested, the accident report is here.