What was found
***WHILE A/C WAS OUT OF SERVICE FOR HEAVY CHECK*** FWD FUSELAGE WET AREA FLOOR STRUCTURE FR17-18 RBL11, RH SEAT TRACK BEAM UPPER FLANGE FOUND CORRODED. FWD FUSELAGE WET AREA FLOOR STRUCTURE FR12-20 RBL11 RH SEAT TRACK BEAM REPLACED IAW SRM 51-41-01, 51-41-02, 51-43-03 & 51-43-04. A/C REMAINS OUT OF SERVICE FOR HEAVY CHECK COMPLETION.