As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROBLEM: THE FLIGHT CREW REPORTED WHILE IN DECENT TO KIAD, " UNCOMANDED RUDDER TRIM TO FULL LIMIT, YAW DAMPER FAILED WHICH IN CAUSED A/C TURN. TRIM INTERRUPT TO REMOVE POWER AND RESET CB. NORMAL OPERATION WAS REGAINED AND THE IRCRAFT LANDED WITHOUT INCIDENT. RESOLUTION: CONTRACT MAINTENANCE VENDOR WAS CALLED TO THE AIRCRAFT. THE KTA 2810 TRIM ADAPTER WAS REMOVED AND REPLACED AND OPS CHECK GOOD IAW AMM 12-B-22-10-07-00A-920A-A NO FURTHER DEFECTS WERE NOTED.