As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INSPECTION OF THE BL 17.1 AND BL 5.7 VERTICAL BEAMS OF THE AFT SIDE OF THE FS 178 BULKHEAD PER BAC S/B 737-53A1225. REVEALED A CRACK IN THE RBL 5.7 BEAM WEB AT WL 185 AND IN THE LBL 17.1 BEAM WEB AT WL 230. THE WEBS OF ALL 4 BEAMS WERE REMOVED AND NEW WEBS INSTALLED TO REPAIR/MODIFY THE BEAMS PER ER/A 381260-14, REV A.