As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT DIVERTED TO LHR ON ACCOUNT OF RUDDER ISSUE. MULTIPLE UNCOMMANDED LEFT YAW INPUTS (NO RUDDER INPUT) AND A/P ENGAGED AT FL 360, M.83 AND 275 KTS IAS. EMERGENCY WAS DECLARED. MAINTENANCE REPORTS DUE TO AHM FAULTING CENTER PCU, REMOVED AND REPLACED CENTER RUDDER PCU IAW AMM 27-21-11. ALL TESTS PASSED OKAY.