As you wish biggles. It seems to me the people getting stressed are in a camp labeled "vested interest".
Sorry the point about being a PPL holder is? Is that supposed to a jibe or a sneer?
Tell you what take it I have zero hours, didn't go to a decent uni, no professional career, no funds and no experience in anything.
So you educate me on how surface hardening (lets call it nitriding) affected this shaft. Then once you have done that perhaps explain that HUMS data and then put the cherry on the cake and tell everyone how everyone seems comfortable when the shaft that failed in October was almost certainly the highest time on any EC225, and again to quote from the AAIB report, no EC225 shaft has flown 4000hrs - when EC love to trot out the 250000hrs statistic which is relevant how?