Narrative:

Supplemental air conditioning air compressor overheated causing the belt to pour smoke into the cabin. While taxi to runway at ZZZZ airport; flight attendant notified first officer she could smell smoke. First officer then informed myself. I had first officer call flight attendant to see how bad was the smoke. After first officer spoke to flight attendant; he said she could now see smoke in the cabin. I told first officer we were going to evacuate/evacuation. I also told first officer to go back and help flight attendant evacuate/evacuation the aircraft; I am shutting down engines. I shut down the engines then informed ATC we were declaring an emergency: smoke in the cabin; evacing passenger on taxiway; could you send the fire trucks; also call my dispatch. I called ground operations; told them we were deplaning passenger on taxiway. At that time dispatch was up on operations frequency. I informed him of our situation. All passenger were offloaded and led away from aircraft by first officer and flight attendant. The firemen boarded the aircraft searching for a fire. Smoke had left the cabin but floor was still very hot. The fire chief wanted to use an ax and the jaws of life to open floor to get to the heat source. I told the firemen that there was no more smoke would like to talk to a mechanic before they opened the floor. A couple of mins later; mechanics from another air carrier showed up; agreeing not to open up the floor. The passenger were shuttled back to the airport without further incident.

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Original NASA ASRS Text

Title: SMOKE IN CABIN OF SAAB 340 DURING TAXI RESULTS IN EMERGENCY DECLARATION AND EVACUATION ON THE TXWY.

Narrative: SUPPLEMENTAL AIR CONDITIONING AIR COMPRESSOR OVERHEATED CAUSING THE BELT TO POUR SMOKE INTO THE CABIN. WHILE TAXI TO RWY AT ZZZZ ARPT; FLT ATTENDANT NOTIFIED FO SHE COULD SMELL SMOKE. FO THEN INFORMED MYSELF. I HAD FO CALL FLT ATTENDANT TO SEE HOW BAD WAS THE SMOKE. AFTER FO SPOKE TO FLT ATTENDANT; HE SAID SHE COULD NOW SEE SMOKE IN THE CABIN. I TOLD FO WE WERE GOING TO EVAC. I ALSO TOLD FO TO GO BACK AND HELP FLT ATTENDANT EVAC THE ACFT; I AM SHUTTING DOWN ENGS. I SHUT DOWN THE ENGS THEN INFORMED ATC WE WERE DECLARING AN EMER: SMOKE IN THE CABIN; EVACING PAX ON TXWY; COULD YOU SEND THE FIRE TRUCKS; ALSO CALL MY DISPATCH. I CALLED GND OPS; TOLD THEM WE WERE DEPLANING PAX ON TXWY. AT THAT TIME DISPATCH WAS UP ON OPS FREQ. I INFORMED HIM OF OUR SITUATION. ALL PAX WERE OFFLOADED AND LED AWAY FROM ACFT BY FO AND FLT ATTENDANT. THE FIREMEN BOARDED THE ACFT SEARCHING FOR A FIRE. SMOKE HAD LEFT THE CABIN BUT FLOOR WAS STILL VERY HOT. THE FIRE CHIEF WANTED TO USE AN AX AND THE JAWS OF LIFE TO OPEN FLOOR TO GET TO THE HEAT SOURCE. I TOLD THE FIREMEN THAT THERE WAS NO MORE SMOKE WOULD LIKE TO TALK TO A MECH BEFORE THEY OPENED THE FLOOR. A COUPLE OF MINS LATER; MECHS FROM ANOTHER ACR SHOWED UP; AGREEING NOT TO OPEN UP THE FLOOR. THE PAX WERE SHUTTLED BACK TO THE ARPT WITHOUT FURTHER INCIDENT.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.