I'm going to get more flaming I'm sure, but here is my take on the recent spate of accidents to the Super Puma family.
REDL - could have been avoided if the correct maintenance procedures had been followed after the epicyclic CHIP warning (epicyclic should have been opened up)
ETAP 225 - pilot error, in part as a result of weak procedures in the Ops Manual and a pilot who, whilst very experienced, was relatively new to night operations in the N Sea
Bond 225 shaft failure - could have been detected before failure if rigorous HUMS monitoring was in place
CHC 225 shaft failure - could have been detected before failure if rigorous HUMS monitoring was in place
Latest L2 - who knows, but it doesn't seem to have been the repeat of any previous technical failures, certainly not a catastrophic failure otherwise the injury pattern and fuselage damage would have been much worse.
So, out of the 5, 3 are maintenance issues, 1 pilot error and 1 that we don't know about. Apart from the unknown latest one, none of them were unavoidable issues with the Super Puma family.