As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4287 THE CREW REPORTED, SELECTED THE NR 1 PACK AND SMOKE CAME THRU THE VENTS. THE CREW ELECTED TO RETURN TO ORD. THE AIRCRAFT WAS REMOVED FROM SERIVCE. PERFORMED ENGINE RUNS AND DID OPERATIONAL CHECK OF NR 1 PACK AND NR 2 PACK SYSTEM IAW EMB 145 AMM 21-51-00. THE OPERATIONAL CHECK WAS GOOD NO DEFECTS OR SMOKE NOTED. NO PARTS REMOVED OR REPLACED. THE AIRCRAFT WAS RETURNED TO SERVICE.