As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CURRENT HMV, HEAVY CORROSION WAS FOUND ON THE FS 1480 FLOORBEAM UPPER CHORD. ADDITIONAL INSPECTION REVEALED THAT THE CORROSION WAS ON AN EXISTING REPAIR (TEE REPAIR) BETWEEN LBL 73 AND LBL 44. THE EXISTING REPAIR WAS REMOVED AND A MODIFIED SRM REPAIR INSTALLED PER BOEING INSTRUCTIONS, AS DOCUMENTED IN ERA/ 466277-14