These two German guys were out test flying this RC helicopter in a field somewhere. The helicopter pilot guy is doing all kinds of air acrobatics like flying the copter upside down, backwards, etc. It looks like he brings it in and is about to land it but he could also have been trying to do another trick. In any event the copter was to close to the ground and it flipped over and slammed down blades first into the grass. At this point the blade keeps spinning and the copter is flopping all over the place (there is no off switch on the controller?). The pilot guy runs out to grab turn it off but the camera guy warns him off (good thing too or he might be missing a hand now). The copter keeps flipping out until I guess the engine burned out or some such at which point they can get close enough and shut the engine off.
Watch the full video below of the RC copter crashing and flipping out all or click over and view it on the host site.