As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 4267 - AFTER TAKEOFF CREW REPORTED DUAL PACK FAILURE AND SMOKE EMITTED FROM VENTS IN THE COCKPIT AND CABIN. CAPTAIN DECLARED AN EMERGENCY AND RETURNED TO ATL. AIRCRAFT LANDED SAFELY WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND A CRACKED HEAT EXCHANGER. REPLACED HEAT EXCHANGER. OPERATIONAL CHECKS WERE GOOD. AIRCRAFT RETURNED TO SERVICE. (M)