As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE PILOT SELECTING THE AFCS TRIM SWITCH ON THE CYCLIC STICK, AFT AND THEN RELEASING, THE PITCH TRIM ACTUATOR CONTINUED TO OPERATE, ATHOUGH THE SWITCH HAD RETURNED TO THE NUETRAL POSITION. A CONDITION KNOW AS "TRIM RUNAWAY". PILOT TOOK APPROPRIATE ACTION. FOLLOWING TROUBLESHOOTING OF THE SYSTEM, THE PITCH TRIM ACTUATOR WAS REPLACED AND THE SYSTEM TESTED, AND ACFT FLOWN SERVICEABLE.