As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF A/C BEGAN TO FISHTAIL. NO YAW DAMPER FLAGS IN VIEW. NO MOVEMENT OF INDICES ON YD INSTRUMENT. RETURN TO AIRPORT FOR LANDING. FOUND LOWER YAW DAMPER FLAG IN VIEW. WILL NOT RETRACT. REPLD YAW DAMP COUPLER. ALSO FOUND LOWER RUDDER POSITION SENSOR SHORTED. REPLACED SAME. YAW DAMP OPEN NORMAL.