What was found
FLIGHT 5169 - AFTER TAKEOFF FROM CVG RECEIVED AN AIR DUCT WARNING FOLLOWED BY LEFT PACK SHUT-OFF CAUTION, FLIGHT RETURNED TO THE FIELD. REPLACED THE LEFT PACK PRE-COOLER.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
FLIGHT 5169 - AFTER TAKEOFF FROM CVG RECEIVED AN AIR DUCT WARNING FOLLOWED BY LEFT PACK SHUT-OFF CAUTION, FLIGHT RETURNED TO THE FIELD. REPLACED THE LEFT PACK PRE-COOLER.