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 REAR FUSELAGE FLOOR SUPPORT STRUCTURE INTERCOSTAL AND SUPPORT ANGLE AT FR 90A CROSSBEAM HAS CORROSION. REPLACED REAR FUSELAGE FLOOR SUPPORT INTERCOSTAL AND SUPPORT ANGLE AT FR 90A LT, IAW SRM 51-43-03, 51-41-01 AND 51-41-02. A/C REMAINS IN CHECK.