I'm thinking vrs

VRS seems unlikely as the primary cause but the 204 was definitely in the envelope for VRS when the helo hit the water. There didn't seem to be much if any wind and his approach was relatively mild. I'm leaning towards mechanical issues with the engine and or fuel system being where I would start my investigation. There were power fluctuation noises right before the bird started settling into the Harbor which makes me think the pilot had engine problems. Too bad the 206 doesn't have a FADEC because that would tell you right away when you have those sort of problems.

Side note, I know exactly where this bird crashed. I recognized it as soon as the video started playing. It's the Arizona Memorial museum right across from the carrier pier. If you ever go to HI I highly recommend you visit the Arizona Memorial and the associated museums.

More than once I have seen water at the bottom of the fuel sample jar... and cloudy JP twice. I was thinking mechanical failure within the fuel system.

Perusing through other flight forums the consensus seems to be some sort of transmission failure which is definitely within the realm of possibility. It will be interesting to find out what the investigators find to be the cause.