As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
***WHILE A/C WAS OUT OF SERVICE FOR HEAVY CHECK*** PASSENGER CABIN REAR FUSELAGE PRESSURIZED FLOOR STRUCTURE, CORROSION FOUND AT GUSSET PLATE AREA OF FRAME 90 RBL 24". REMOVED AND REPLACED GUSSET PLATE IAW SRM 51-41-02. A/C REMAINS OUT OF SERVICE FOR HEAVY CHECK COMPLETION.