As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4199 THE CREW REPORTED SMOKE IN THE COCKPIT AND CABIN WITH THE AUXILARY POWER UNIT BLEED AND AIR CYCLE MACHINE PACKS NR 1 AND 2 ON. THE SMOKE CLEARED WHEN BOTH PACKS WERE TURNED OFF. THE AIRCRAFT RETURNED TO BLOCKAND WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE NR 1 AIR CYCLE MACHINE IAW EMB 140 AMM 21-51-03. THE OPERATIONAL CHECK WAS GOOD. NO HAZE NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.