Originally Posted by
SASless
Well kinda maybe perhaps.....if one includes vertical pins and TT Bars and perhaps the Hub as being part of the "rotor blades".
Those failures could release one of the blades and create the kind of Imbalance that would result in a catastrophic failure of the aircraft but not be a "blade" failure.
I would call it a blade retention failure. It would matter not which brand of blade was installed in that case.
If the Tail Boom failed structurally and found its way up into the rotor system and thus create a "blade failure" would that be different than a failure in one of the Rotor Blades occurring without any outside cause akin to that?
I am trying to sort out how you are defining "Blade Failure".
To assess blame we ought to be very specific as to how we allocate "blame".
Care to expound upon your post to clarify your observation which in general I fully agree with but I am still waiting for information that points me to the root cause and originator of the process that caused the aircraft to come apart as it did in apparent level cruise flight in benign weather.
All of the pictures of the recovered rotor system showed the hub, TT straps, and blade pins/roots intact. Does not appear to be a retention failure (unless we consider the retention of the main balance pocket, which is something I alluded to earlier in this thread)
Occam's razor suggests more and more this was likely an issue with the VH blades and their well documented, however poorly explained and understood, vertical hop phenomenon - between the noticeable tail wag at ground idle of the accident aircraft before the incident, to the flight envelope at the moment of the incident, to the condition of the rotor system at recovery.
Based on the construction and analysis approach used, as a career blade and rotor designer I still do not understand how the 206 VH blade design was certified in the first place.