Aegir, Prehar, Runaway101,
I have not saying that HK accident has surely occurred due to a bird strike which has subsequently caused an unbalance of tail rotor,
I would like to stress anyway that a bonding failure of a blade can be - as occurred in many accidents in the pasts on helos - a consequence of a severe unbalance of a rotor which may lead to the accidents that we have seen so far (i.e. bird strike, water impact, maintenance poor quality, and so on).
It is more than fair to raise an Alert Mandatory SB/authority AD on such blades, simply because they are critical components of an helicopter and it is unacceptable to have such debondings on the fork:
however, in neither of the 3 accidents in subject there is any proof of a TRB failure as leading cause of the event - CAD report doesn't state that ("investigation is ongoing"), Qatari accident has not reported any evidence of this kind and the Brazil one is too recent for determining any preliminary cause.
Prehar, just a further comment for your (fair) observation: regarding the failure mode, I agree that it is the same, but we have to segregate the way how a component fails from the cause (static, dynamic failure) that has provoked.
I sustain your last point on which a manufactured should react quickly not only (...) for presumed accident causes, but also for quality concerns. If I were the owner and the maintainer of an AW139, I would simply not accept to fly being aware that TR Blades debonds in that area.