As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN CABIN FLOOR STRUCTURE STA 560 TO STA 580 BL 0 INTERCOSTAL WEB UPPER FLANGE HAS 21 HOLES THAT WERE PREVIOUSLY ELONGATED. REMOVED INTERCOSTAL WEB AND T-ANGLES. FABRICATED NEW INTERCOSTAL AND HEAT TREATED. SEE WORK ORDER 00036352. FABRICATED T-ANGLE AS PER DRAWING 65-59896. INSTALLED AS PER 51-30-2.