As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE A/C WAS IN FOR HEAVY CHECK FOUND GUSSET ON FR 90 FOR FLOOR PANEL 252ERF, AFT PUCK POSITION HAS CORROSION. MX REMOVED AND REPLACED GUSSET PLATE PN 170-60259-001 AT FR 90 IAW EMB 175 SRM 51-41-02. A/C REMAINS IN CMH FOR HEAVY CHECK COMPLETION.