What was found
***WHILE A/C WAS OUT OF SERVICE FOR HEAVY CHECK*** PASSENGER CABIN CF III FLOOR STRUCTURE, CORROSION FOUND AT LONGITUDINAL BEAM AREA BTW FR86-89 RBL 12". PASSENGER CABIN CF III FLOOR STRUCTURE, LONGITUDINAL BEAM REPLACED BTW FR86-89 RBL 12" IAW SRM 51-43-03 & 51-41-01. A/C REMAINS OUT OF SERVICE FOR HEAVY CHECK COMPLETION.