As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT FOR FLIGHT 4042 THE CREW REPORTED A SMOKE SMELL IN THE COCKPIT AND CABIN WITH THE APU ON AND PACK 1 OR 2 SELECTED. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE NR 2 RECIRCULATION FAN IAW EMB 145 AMM 21-24-01. OPERATIONAL CHECK AND LEAK CHECK WAS GOOD. NO ODOR OR SMOKE SMELL NOTED AT THIS TIME. THE AIRCRAFT WAS RETURNED TO SERVICE.