What was found
DURING THE B6 BASIC CHECK AT EAMS, THE RT WING LOWER REAR ROOT SKIN, P/N 170-01423-010, WAS DISCOVERED CRACKED DURING INSPECTION AT THE SPAR II AND RIB 4A JUNCTION. THE CRACK WAS VERIFIED AT APPROXIMATELY 0.492 INCHES LONG THROUGH NDT. REFERENCE ETD2019-170-119402 FIGURES 1-3 FOR DETAILS. THE CRACK IS LOCATED APPROXIMATELY 0.5 INCHES OUTBOARD OF THE RIB 4A LOWER SKIN DOUBLER, P/N 170-26653-004. THIS EO IS BEING ISSUED TO PROVIDE INSTRUCTIONS TO ACCOMPLISH A TEMPORARY REPAIR OF THE CRACKED RT WING LOWER REAR ROOT SKIN, P/N 170-01423-010, AT THE SPAR II AND RIB 4A JUNCTION, BY CUTOUT AND INSTALLATION OF A SINGLE EXTERNAL REPAIR DOUBLER WITH A FILLER PER ETD2019-170-119402. THE REPAIR DOUBLER, P/N 171-22053-001, IS BASICALLY AN EXTENSION OF THE ORIGINAL DOUBLER P/N 170-26653-004. BECAUSE THE RT WING LOWER REAR ROOT SKIN IS A PSE AND FCS, ACCOMPLISHMENT OF THIS EO HAS BEEN CLASSIFIED BY ENGINEERING AS A MAJOR REPAIR DUE TO STRENGTH RESTORATION. EO E175-57MR-015 IS BEING ACCOMPLISHED BY WO 2721589.