What was found
THIS EO IS BEING ISSUED TO PROVIDE INSTRUCTIONS TO ACCOMPLISH THE PERMANENT REPAIR OF CORROSION DAMAGE TO THE FWD CABIN FLOOR STRUCTURE, LT FWD SEAT TRACK PN 170-03264-001 AT FRAME 19, Y=-273. THE APPROX DAMAGE DIMENSIONS ARE AS FOLLOWS, 1.8 INCHES X 1.6 INCHES TO A MAXIMUM DEPTH OF .010 INCH DEEP. 1.10 INCHES X 0.90 INCH WITH 100% MATERIAL LOSS & 0.95 INCH X 1.0 INCH WITH 100% MATERIAL LOSS. THE LT SEAT TRACK IS NOT CLASSIFIED AS FCS IN FCSD-3575, BUT IS CLASSIFIED AS PRIMARY STRUCTURE IN SRM PART II 51-00-04. ACCOMPLISHMENT OF THIS EO HAS BEEN CLASSIFIED AS A MAJOR REPAIR DUE TO STRENGTH RESTORATION OF PRIMARY STRUCTURE. EO E175-53MR-198.1 WILL BE ISSUED TO ACCOMPLISH FOLLOW UP INSPECTIONS IAW ETD2015-170-064731 ANAC DER FORM ATTACHED. REF INSPECTION INSTRUCTIONS, TASK 53-10-027-0001, INTERNAL GVI THRESHOLD OF 25,202 FC, INTERVAL OF 25,202 FC, IS SUFFICIENT & IS MET USING THE INSPECTION REQUIREMENTS, MPG & MRBR REVISION 10. THRESHOLD IS COUNTED SINCE NEW. ACCOMPLISHMENT OF THIS MAJOR REPAIR IS ON EO E175-53MR-198 UNDER WO 1933468.