So you think when the connected blade went full stroke that is what caused the blade to fail?
Probably yes, too much aerodynamic load, combined with vibration, which was not symmetrical. That also begins to overload the TR gearbox attachment and mechanisms.
Then what caused the unconnected blade to fail in the same location at outboard edge of the finger doubler? Its hard to tell from the pics but it looks more like that both blades hit the tailboom which caused the failure at the same location.
I understand that the 222 TR is a teeter hub just like the 206's. I have found that sometimes when you have a fatiguing force, the 180 degree opposed component suffers similar loads, just because the first one (blade) is. The end of the finger doubler is the first weak point outboard of the hub.
And only after both blades failed did the TR output quill assembly depart instead of at the 1st blade failure. Quite possible there could have initially been a TR output drive failure of some sort that started the blade failures??
'Could be, once the tail rotor gearbox and drive line components are being subjected to those high vibrations/loads, more is going to let go. Once one tail rotor blade departed, there is no way that anything at the TR gearbox could ever be near balance limits ever again, even the second blade also departing. Shaking itself to death is just a matter of time at that point...