You want what
As a fellow engineer, i have seen first hand, a gearbox complete with gearbox suspension bars,head and blades ripped out from the box structure Download report:
AS355F1, G-XCEL 07-06.pdf (888.58 kb) the forces involved are incredibly high.
It is only my supposition, looking from the photo's of the wreckage, that the head separated at the ring gear casing (conical housing) to main gearbox casing.
With regard to the inspection of the gearboxes would it not have been prudent of the authorities to ground these machines, until a visual inspection of the epicyclic gears has been carried out?