As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHL - FL 16 - EN ROUTE PHL-CDG - CREW RECEIVED THE EICAS MESSAGE 'AUTOPILOT DISC' AND THE A/P DISC LIGHT WHILE THE AUTOPILOT WAS STILL IN 'CMD'. CREW ALSO RECEIVED AURAL WARNINGS. THE AUTOPILOT WAS DISENGAGED AND COULD NOT BE REENGAGED. FLT RETURNED TO PHL AND LANDED WITH NO FURTHER INCIDENT. MAINTENANCE FOUND THE FIRST OFFICERS DISCONNECT SWITCH STICKING AND THE CENTER FCC FAILED. BOTH WERE REPLACED. (M)