As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE PILOT WAS MAKING AN APPROACH WHEN THE ROTOR RPM STARTED TO OVERSPEED. HE CONTROLLED THE RPM USING THE THROTTLE AND ABORTED THE APPROACH. HE FLEW TO A MAINTENANCE BASE WHERE HE CONDUCTED A RUN-ON LANDING WITHOUT FURTHER INCIDENT. INVESTIGATION REVEALED THAT THE FITITNG ON THE ACCUMULATOR HAD FAILED.