As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(LG NR 000173) AIRCRAFT DEPARTED, CLIMBING THROUGH FL370 AT M.58, THE YAW DAMPER BEGAN A SERIES OF LT TO RT INPUTS INCREASING TO FULL SCALE DEFLECTION AT A RATE OF APPROXIMATELY ONE PER SECOND. THE AUTOPILOT WAS TURNED OFF, AND THE MALFUNCTION CONTINUED. TURNED YAW DAMP OFF, AND THE MALFUNCTION CEASED. CREW NOTIFIED ATC AND RETURNED TO AIRPORT. PHYSICAL LOCATION OF FAILED PART IS IN THE AFT TAIL CONE COMPARTMENT. (CE09200404353)