As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 3312 AFTER LEVEL OFF AT FL360 A/C WOULD "FISHTAIL" YAW BACK + FORTH FOR ABOUT 10 SEC, STOP FOR A BIT THAN START AGIAN, AS THOUGH DANCING ON RUDDER PEDALS. LASTED ABOUT 1 HOUR CHANGING AUTO PILOT NO HELP. CORRECTIVE ACTION: T/S. ALL APPLICABLE TESTS OK AND NO FAULTS AND COULD NOT DUPLICATE RUDDER OSCILLATION. PER TSM REMOVED AND REPLACED FCPC 1 AND TESTS OK. PERFORMED SUCCESSFUL LAND TEST. (4704682)