What was found
MCN - MAJOR REPAIR - DURING C-16 CHECK A 1/2" CRACK WAS FOUND AT FASTENER HOLE OF MAIN CABIN FLOOR SUPPORT UPPER ATTACH ANGLE BS 500D - BS 520, BL O. MAINTENANCE REMOVED DAMAGED MAIN CABIN FLOOR SUPPORT UPPER ATTACH ANGLE BS 500D - BS 520, BL O; FABRICATED A NEW REPLACEMENT FLOOR SUPPORT UPPER ATTACH ANGLE IAW B737-300 SRM 51-40-05, PG. 1 & 4, FIG 2; AND INSTALLED REPAIR PART IAW B737-300 SRM 51-40-02, PG. 1-4, 10-11, 28, & 32-35, FIG. 6, AND SRM 51-40-04, PG. 2, TABLE 1.