Lu and I were basically in agreement (in another thread) about the cause of the rotor blade failure when this accident happened, namely that the titanium spar would not take kindly to a lightning strike, due to the unique properties of titanium.
I noticed that after the accident, the FAA and Sikorsky were involved in an AD to recall all S-76 rotor blades in service that had suffered previous lighting strikes. If memory serves me, there were 8 known blades in service at that time with this history.
I doubt after this accident, that ANY titanium spar rotor blade will EVER be returned to service after a lightning strike. Again Shawn is right, a foolproof NDT method of testing would be required to properly certify a titanium spar rotor blade for return to service after a lightning strike, and no such method exists at this time. Until such a method is developed, the only prudent course of action is to ALWAYS remove such a rotor blade from service, permanently.