As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:C FX LOWER FUSELAGE EXTERNAL SKIN SURFACE FWD LAVATORY SERVICE PAN FWD ATT PLATE FOUND CORRODED AT LT STA 545 STR 46L TO STR 47L. CORROSION BLEND OUT THROUGH WHOLE THICKNESS .5 X 1 INCH. FX BS 540 BETWEEN STR 46L TO STR 47L LAV SVC PAN ATTACHED BEAM STRAP REPAIRED AS PER HX RS R-53-21-35363 & ENGINEERING FILE NUMBER : 747-53-20283. FOLLOW THE INSP INTERVAL AS PER SRM 53-30-03 FIG 1 TABLE IV USING EXTERNAL LFEC INSP METHOD.