As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION TYPE-C, CORROSION FOUND TO BE OUT OF LIMITS ON INTERCOSTAL ATTACHED TO STRINGER AT FS 312 STR 18 APPROX 12 INCHES BELOW FLOORBEAM. REF N/R 490324 REMOVED, FABRICATED AND INSTALLED INTERCOSTAL PER BOEING DWG 69-22183 AND SRM 51-10-2, 51-30-2.