As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE AIRCRAFT WAS IN HEAVY CHECK MAINTENANCE FOUND THE LEFT FLOORBEAM CORRODED BETWEEN FRAME 86 AND 89. MAINTENANCE REMOVED AND REPLACED THE LEFT FLOORBEAM BETWEEN FRAMES 86 AND 89 IAW EMB 170 SRM 51-40-02 AND 51-43-01. THE AIRCRAFT IS OUT OF SERVICE IN HEAVY CHECK.