As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE:C RT WING T/E CAVITY REAR SPAR LOWER SKIN FOUND CORRODED BETWEEN WS 510 & WS 515 (ACCESS FROM T/E PNL 671AB). CORROSION BLEND OUT 0.074 X 2 X 5 INCH EXCEED SRM LIMIT. RT WING T/E CAVITY REAR SPAR LOWER SKIN UPPER SURFACE AT WS 516.5 REPAIRED AS PER RS R57-26-35436 AND REF UPS EO B747-5720-23814-A.