What was found
THIS EO IS BEING ISSUED TO PROVIDE INSTRUCTIONS TO ACCOMPLISH THE PERMANENT REPAIR OF CORROSION DAMAGE TO THE AFT CABIN FLOOR STRUCTURE RT AFT SEAT TRACK, PN 170-86082-003 AT FRAME 84. THE APPROX DAMAGE DIMENSIONS ARE AS FOLLOWS. 3.0 INCHES X 1.0 INCH WITH 100% MATERIAL LOSS. 1.2 INCHES X .85 INCH DEEP X .051 INCH DEEP & 2.50 INCHES X .40 INCH X .063 INCH DEEP. BECAUSE THE FLOOR TRACK IS A PSE, ACCOMPLISHMENT OF THIS EO HAS BEEN CLASSIFIED AS A MAJOR REPAIR DUE TO STRENGTH RESTORATION. THIS IS NOT CLASSIFIED AS FCS, BUT WILL REQUIRE FOLLOW UP INSPECTIONS AFTER THE PERMANENT REPAIR ACCOMPLISHMENT. EO E175-53MR-222.1 WILL BE ISSUED TO ACCOMPLISH THE PERMANENT REPAIR WITHIN THE 7,500FC FLY BY. EO E175-53MR-222.2 WILL BE ISSUED TO ACCOMPLISH THE FOLLOW UP INSPECTIONS IAW ANAC DER FORM ATTACHED. TASK 53-23-005-0001, INTERNAL GVI THRESHOLD OF 20,483FC OR 27,242FH, INTERVAL OF 10,133 FC OR 13,476FH IS SUFFICIENT & IS MET USING THE INSPECTION REQUIREMENTS MPG & MRBR REVISION 11. THRESHOLD IS COUNTED SINCE NEW. ACCOMPLISHMENT OF THIS MAJOR REPAIR WAS ON EO E175-53MR-222 UNDER WO 1991116.