Originally Posted by
birmingham
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.
The other issue with the AIBN investigation is the lack of material from the epicyclic that has been recovered, so at this stage they wouldn't be able to confirm too much. With REDL the AAIB recovered all of the stage one gears, 7 complete stage 2 gears still attached to the planet carrier and 75% of the failed gear, even then the evidence of fatigue was limited to part of one fracture face on a single piece of the failed gear.