What was found
MCN - MAJOR REPAIR - DURING C-15 CHECK A .5 INCH CRACK WAS FOUND IN STRINGER 18 RIGHT LOWER LEG STIFFENER, AFT SIDE OF BS 312. MAINTENANCE REMOVED CRACKED STRINGER TIE AT BS 312, STR 18 RIGHT; FABRICATED A NEW REPLACEMENT STRINGER TIE PER DWG 65-45810; INSTALLED REPAIR PART IAW B737-300 SRM 51-40-02 FIG 8, 12 & 14.