As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCN - MAJOR REPAIR - DURING C-21 CHECK DISCOVERED CRACK .322 INCHES LONG AT FORMED CHANNEL LOCATED AT BS 178 WL 230 RBL 17.1. MAINTENANCE REMOVED AND FABRICATED NEW CHANNEL IAW BOEING DWG 9-63089. INSTALLED FABRICATED REPAIR PARTS AT BS 178 WL 230 RBL 17.1 IAW BOEING 737-300 SRM 51-40-02-0 FIG 212.