As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH FLIGHT 2684 - PILOT REPORTED A SMELL OF SMOKE IN COCKPIT AND CABIN ASSOCIATED WITH A LARGE THUD. THE AIRCRAFT RETURNED TO IAH AND LANDED WITHOUT INCIDENT. A DUCT WAS FOUND DISLODGED ON THE RIGHT AIR CONDITIONING PACK. THE DUCT WAS RESECURED, OPERATIONAL AND LEAK CHECKS WERE SATISFACTORY AND THE DISCREPANCY WAS CLEARED.