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Regarding HK, the TGB detachment could be consistent with an out-of-balance Tail Rotor due to the water impact, and in case of TR Blade detachment, it has never been declared that the one subject of failure is due to - despite debonding discrepancies which are subject of the Mandatory SB on them introducing a conservative preventive maintenance requirement,
Regarding TR Blades, it is necessary to assess if the failure has been occurred dynamically or statically: in HK the reason could be an out-of-balance condition for a bird strike, while in Qatar the TRB failure with the consequent TGB detachment could have been caused by a not removed rigging tool.
Regarding HK accident, please check the HK CAD interim statement:
http://www.cad.gov.hk/reports/Interi...B-MHJ_e%20.pdf
I absolutely don't want to defend AW139 from its debonding topics - I consider the TR Blades debonding a quality concern which AW should have already assessed in the past and with a reasonable time of resolution -
but as per my experience in aviation, frequently a suspicious accident driver is discovered, during the investigation assessment, a accident-driven failure (i.e. b MR/TR Blades breakage/major debonding consistent to a catastrophic unbalance of a rotor for external factors).
In other words, the smoking gun results only a component damaged or failed due to the energy released by the accident conditions.
The CVDR and HUMS data will contribute to clarify what sadly happened in Brasil to our Senior colleagues.