Clarifying mtoroshanga's point:
The fatal accident on the AS332L mentioned was to Helikopter Service aircraft LN-OPG 10 years ago.
The HUMS did NOT give prior notice because the sensor had not been repaired having been unservicable for for a couple of months. So fixing the sensor was ignored not a the HUMS analysis.
http://www.havarikommisjonen.no/defa...&V_ITEM_ID=247
The aircraft was at a remote base flying 50 hours a week with one engineer.
However you would think that a decade on new aircraft would be better at detection!