There was a fatal AW109 Koala accident here in Brazil w/ 7 aboard about a month ago, preliminary reports show the aircraft had engine failure in cruise flight and one of the blades was fond about 500 meters away from the crash site, it is strongly believed this blade came off during an overspeed from the transitioning (cruise/eng failure/flare to iniciate autorotation) as the Aw109 allows very little rotor overspeed.
I would think twice before letting my rotor overspeed
