As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - FLT 682 - EN ROUTE SFO-ORD, ON FINAL APPROACH DETECTED A LOUD BANG AND LEFT SIDE PACK TURNED OFF. LEFT SIDE DUCT LIGHT ILLUMINATED. LANDED ORD WITHOUT FURTHER INCIDENT. REPLACED PNEUMATIC DUCTS AT WING AREA. ACCOMPLISHED LEAK CHECKS IAW THE MM. NO LEAKS NOTED. SYTEM GROUND CHECKED NORMAL OPERATION. (M)