On the G-REDL accident the failure occured in the second stage planetary gear and there was significant evidence of both fatigue cracks and that the unit had been in contact with metal particles in the days before the crash. In this one the AIBN says that detailed analysis has not yet taken place but that initial inspections didn't reveal any evidence of fatigue. That may (or may not) suggest a different failure mode this time but it will be necessary to await detailed analysis - they may also need some of the missing parts of the gear to be definitive.