As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
POWER TURBINE GOVERNOR FLYWEIGHTS AND BUSHING FAILED CAUSING GOVERNOR TO DUMP PY AIR TO FUEL CONTROL UNIT ALLOWING POWER TO DROP TO 50 PERCENT. ENGINE WAS FEATHERED AND RETURNED TO HOME BASE WHERE GOVERNOR WAS REPLACED WITH OVERHAULED UNIT AND CHECKED OPERATION AND FLIGHT TEST.