As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCN - MAJOR REPAIR - DURING C-19 CHECK CORROSION WAS FOUND ON TRANSVERSE FLOORBEAM UPPER CHORD AT BS 986 BETWEEN RBL 18 AND RBL 43, WL 208. MAINTENANCE BLENDED OUT CORROSION ON TRANSVERSE FLOORBEAM UPPER CHORD AT BS 986 BETWEEN RBL 18 AND RBL 43; FABRICATED A REPAIR STRAP; INSTALLED REPAIR PART IAW B737-300 SRM 53-00-51 FIG 203.