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 170-86081-003 AT FRAME 84. THE APPROX DAMAGE DIMENSIONS ARE AS FOLLOWS. 2.30 INCHES X .90 INCHES TO A MAXIMUM DEPTH OF .022 INCH DEEP. 1.30 INCHES X 1.0 INCH TO A MAXIMUM DEPTH OF .024 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 REQUIRES FOLLOW UP INSPECTIONS THAT WILL BE ACCOMPLISHED ON EO E175-53MR-173.1 IAW ANAC DER FORM ATTACHED. TASK 53-23-005-0001, INTERNAL GVI THRESHOLD OF 20,000 FLIGHT CYCLES OR 26,600 FLIGHT HOURS, INTERVAL OF 5,099 FLIGHT CYCLES OR 6,781 FLIGHT HOURS, IS SUFFICIENT & IS MET USING THE INSPECTION REQUIREMENTS. MPG & MRBR REVISION 10. THRESHOLD IS COUNTED SINCE NEW. THIS MAJOR REPAIR WAS ACCOMPLISHED ON EO E175-53MR-173 UNDER WO 1900835.