As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CLIMB, AN AIRCRAFT EXPERIENCED AN UNCOMMANDED AUTOFEATHER CAUSED BY NR 1 ENGINE TORQUE FLUCTUATIONS. WITH THE NR 1 PROP FEATHERED AND ENGINE STILL RUNNING AT REDUCED POWER, THE PILOT RETURNED TO BASE. PEC REPLACED. ENGINE RUNS CARRIED OUT. A/C RETURNED TO SERVICE.