As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STATUS MSGL ENG A-O VALVE. CREW REPORT PROBLEM ON LEFT ENGINE SEE DF647 BOTH ITEMS RELATED. BITE CHECK SHOWS EEC CH A AOC FD-BK FAIL. AOC VALVE DEACTIVATED PER MEL CARD 75040. VALVE IN OPEN POSITION AND PLUG DISCONNECTED AND SAFTIED. DF PLACARD PLACED ON LOWER EICAS. ABOVE DEACTIVATION FOR DF646. DF646 AND DF647 NEED TO BE WORKED CONCURRENTLY DUE TO THIS CAT 1 FAULT CAUSED BY DF646.