What was found
DURING BASIC CHECK, INSPECTION DISCOVERED THE RT WING LOWER REAR ROOT SKIN, P/N 170-01423-010, CRACKED AT THE SPAR II AND RIB 4A JUNCTION (REF EO E175-57MR-010, PHOTOS 1 AND 2). THE CRACK WAS VERIFIED AT APPROXIMATELY 7/32 INCH LONG THRU HFEC NDI. THE CRACK IS LOCATED APPROXIMATELY 0.5 INCH OUTBOARD OF THE RIB 4A LOWER SKIN DOUBLER, P/N 170-26653-004. THIS EO IS BEING ISSUED ACCOMPLISH A TEMPORARY REPAIR, CUTOUT AND INSTALLATION OF A SINGLE EXTERNAL REPAIR DOUBLER WITH A FILLER PER ETD2018-170-065489. THIS EO HAS BEEN CLASSIFIED BY ENGINEERING AS A MAJOR REPAIR DUE TO STRENGTH RESTORATION.