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-18 CHECK A 1 INCH CRACK WAS FOUND ON FRAME BETWEEN STRINGERS 28 LT AND 28 RT, AT BS 500. MAINTENANCE REMOVED DAMAGED AREA OF FRAME BETWEEN STRINGERS 28 LT AND 28 RT, AT BS 500; FABRICATED A REPAIR DOUBLER AND FILLER; INSTALLED REPAIR PART IAW B737-300 SRM 53-00-07, FIG 201 PG 202-203.