As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LCQ - MAJOR REPAIR - DURING C-19 CHECK A .75 INCH CRACK AND CORROSION WERE FOUND ON AFT CABIN FLOOR WEB WHERE FLANGE ATTACHED TO SEAL AND RETAINER AT BS 1006, RBL 38. MAINTENANCE CUT OUT DAMAGED SECTION OF FLOOR WEB AT BS 1006, RBL 38; FABRICATED A REPAIR DOUBLER; INSTALLED REPAIR PART IAW B737-300 SRM 51-70-13 FIG 1.