As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CURRENT HMV, CORROSION WAS FOUND ON THE 1681 FLOORBEAM, ON THE UPPER CHORD (UPPER AND LOWER SURFACE). DUE TO THIS, THE UPPER CAP WAS CUT OUT AND REMOVED PER BOEING INSTRUCTIONS, AND A REPLACEMENT UPPER CAP INSTALLED AS DOCUMENTED IN ER/A 470312-14 (CATEGORY A REPAIR).