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 LT AFT SEAT TRACK PN 170-86081-005 AT FRAME 84. THE APPROX DAMAGE DIMENSIONS ARE AS FOLLOWS 1.45 INCHES X .78 INCH TO A MAXIMUM DEPTH OF .041 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 FCS, BUT REQUIRES FOLLOW UP INSPECTIONS THAT WILL BE ACCOMPLISHED ON EO E170-53MR-025 1 IAW ANAC DER FORM ATTACHED. TASK 53-23-005-0001 INTERNAL GVI THRESHOLD OF 20,000FC OR 26,600FH, INTERVAL OF 5,099FC OR 6,781FH, IS SUFFICIENT & IS MET USING THE INSPECTION REQUIREMENTS MPG MRBR REVISION NR 9. THRESHOLD IS COUNTED SINCE NEW. THE REPAIR ACCOMPLISHMENT IS ON EO E170-53MR-025 UNDER WORK ORDER 1560492.