As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ACFT EXPERIENCED ENGINE AND ROTOR OVERSPEED DUE TO LOSS OF SIGNAL FROM TACH POINTS. THE CAM FOLLOWER ON THE TACH POINTS HAS EXCESSIVE WEAR WHICH DID NOT ALLOW THE CAM TO ACTUATE THE POINTS. THE EXCESSIVE WEAR ON THE TACH POINT CAM FOLLOWER WAS DUE TO LACK OF LUBRICATION. THE CAM FOLLOWER FELT LIKE IT DID NOT HAVE ENOUGH OIL.