As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 1800 - EN ROUTE DEN-ORD - HEARD A LOUD BANG AFT OF AIRCRAFT. PRESSURE FLOW LIGHT ILLUMINATED AND LATER LIGHT TURNED OFF. DETECTED LOSS OF CABIN PRESSURIZATION. LANDED ORD WITHOUT FURTHER INCIDENT. ACCOMPLISHED SINGLE PACK OPERATIONS CHECK. NO DEFICIENCIES NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)