As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY CHECK MAINTENANCE FOUND CORROSION ON CENTER FUSELAGE III FLOOR SUPPORT STRUCTURE DOUBLER AT FR 85-86 LT SIDE. CENTER FUSELAGE III FLOOR SUPPORT STRUCTURE AT FR 85-86 LT SIDE REPLACED WITH NEW DOUBLER, IAW SRM 51-41-01 AND 51-43-03. A/C REMAINS IN CHECK.