What was found
WHILE AIRCRAFT WAS IN HEAVY CHECK MAINTENANCE FOUND THE RIGHT AFT SEAT TRACK EXTENSION FRAME 86 TO 89 CORRODED. MAINTENANCE REMOVED AND REPLACED THE SEAT TRACK EXTENSION IAW EMB 170 SRM 53-23-10, 51-43-00, 51-40-02, AND 51-43-03. THE AIRCRAFT IS OUT OF SERVICE IN HEAVY CHECK.