As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2193 (OTH-PDX) ON APPROACH WITH THE AUTOPILOT ON, EXPERIENCED A UNCOMMANDED ROLL TO THE LEFT. AUTOPILOT WAS TURNED OFF AND THE WHEEL APPEARED TO BE JAMMED (NO MOVEMENT POSSIBLE). CONTROL THEN BECAME UN-JAMMED AND OPERATED NORMALLY AFTER A FEW SECONDS. LANDED WITH SPOILER CONTROL ONLY. EMERGENCY DECLARED WITH ATC. LANDING UNEVENTFUL. MAINTENANCE REPLACED THE AUTOPILOT AILERON SERVO. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.