As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LCQ - MAJOR REPAIR - DURING C-18 CHECK 2 EACH 1" CRACKS WERE FOUND ON KEEL BEAM PANEL BETWEEN WHEEL WELLS AT FORWARD END BS 685. MAINTENANCE REMOVED EXISTING DOUBLER AT BS 660 TO BS 690; STOP DRILLED CRACKS AND PERFORMED HFEC INSP TO VERIFY CRACKS CONTAINED; FABRICATED A REPAIR DOUBLER; INSTALLED REPAIR PART IAW B737-300 SRM 53-60-12, FIG. 202, PG. 204.