What was found
(AIRCRAFT NOT GROUNDED) (DEFECT DISCOVERED DURING AC HEAVY MX) AFT CARGO COMPARTMENT FLOOR STRUCTURE, CORROSION FOUND AT STRINGER 41L BTW FRAME 55-56 AREA. AFT CARGO COMPARTMENT FLOOR STRUCTURE, AT STRINGER 41L BTW FRAME 55-56 AREA PERMANENTLY REPAIRED AS PER SRM 53-41-13-300-010, REPAIR PRINCIPLE 1, FIGURE 002 SHEET 1, REV. 159. REPAIR CATEGORY A, NO FURTHER ACTION REQUIRED.