It seems surprising that after 5 years there has not been a test to destruction of the gear box design involved.
AFAIK, we have a plausible failure sequence, but no firm take away conclusions that would allow future designers to avoid a similar disater.
Can anyone shed light on the state of play in this area?
Read post #1916 "between the lines". Each first paragraph sums it up and is a "hole in the cheese".
You can test the gearbox to destruction but that would be pointless unless you had some idea as to what you would do to initiate it.
This is a seriously deep rabbit hole!!