As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE TROUBLESHOOTING PRESSURIZATION PROBLEM FOUND CRACKING AT FASTENER ON FORWARD PRESSURE BULKHEAD BOX ASSEMBLY. REPAIR WAS COMPLETED USING APPROVED DATA. 4TH AIRCRAFT FOUND WITH CRACKING IN THIS AREA. PAY SPECIAL ATTENTION TO THIS AREA ON OLDER 500 MODEL CITATIONS.