As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CARGO BAY INTERCOSTAL AT BS 727A - 727B, STRINGER 25L IS CORRODED ON THE LOWER SIDE. ACFT GROUNDED. BLENDED THE CORROSION ON THE INTERCOSTAL AND FOUND IT TO BE OUT OF LIMITS IAW SRM 53-60-53-1A. INSTALLED A NEW INTERCOSTAL IAW SRM 51-40-02-0G-0.