As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NUMBER 6 FLAP TRACK, AFT MOUNT SURFACE CORROSION. CORROSION REMOVAL BY MACHINING EXCEEDED THE ALLOWED OHM REPAIR DEPTH. THE AFFECTED PART NUMBER IS 65B17067-4. THE REPAIR IS APPROVED BY THE BOEING COMPANY PER ECRA N639FE-57-B747-013-EAC.