What was found
MCN - MAJOR REPAIR - DURING C-17 CHECK 3 EACH .25 INCH CRACKS WERE FOUND ON SKIN AT LOWER ROW OF FASTENER HOLES STR 4 RT, BS 500B+1, BS 500B+2, AND BS 500B+15. MAINTENANCE CUTOUT AND REMOVED CRACKED SKIN AT STR 4 RT, BETWEEN BS 500A+18 & BS 500B+4, AND BS 500B+13 & BS 500B+16; PERFORMED A HFEC INSPECTION OF CUTOUTS TO VERIFY NO CRACKS EXIST; FABRICATED 2 EACH DOUBLERS, 2 EACH FILLERS, 2 EACH INTERNAL DOUBLERS, AND A TAPERED FILLER; INSTALLED REPAIR PARTS BS 500A+18 - BS 500B+17 IAW B737-300 SRM 53-00-01PG 362, FIG 228.