Narrative:

We were heading to runway for departure. The captain and I were completing the 'before takeoff check' when the the flight attendant chimed us on the interphone and said there was a strong burning smell in the cabin. I asked her if she could see any smoke or could tell where it was coming from. She said she would check and call us back. The captain was monitoring the interphone conversation on his headset and we began discussing the situation. We decided to pull off the taxiway until we determined what was wrong. I called ZZZ ground and told them that we needed to pull off the taxiway. I believe I said it was because we had a burning odor in the cabin but cannot remember. We also decided to shut off all bleed air and supplemental AC as that could be a cause of the odor. The captain closed the engine bleeds and I shut down the supplemental AC. About that same time the flight attendant chimed us again and said the burning odor was getting stronger and worse. The captain told me to call ground and tell them about our situation and request the fire department/arff as well as to prepare to exit the aircraft. I attempted numerous times to contact ground but due to a congested frequency did not make contact with them for about 15 to 25 seconds. When I did get through I told the controller that we were shutting down on the taxiway and requesting the fire department. He asked why. I said; 'we have a burning odor in the cabin.' during this time the captain proceeded to shut down the aircraft. After I made the radio call to ground I told the captain I was going to help flight attendant get the passengers off. He approved of the plan and continued powering down the aircraft. As soon as I opened the cockpit door I was immediately hit with the burning smell/odor. It smelled similar to burning plastic. I do not recall seeing any smoke. As soon as the propeller stopped spinning I told flight attendant to go ahead and open the door and drop the stairs. She did and we began a very orderly and efficient deplaning. I said something along the lines of follow me to the passengers and led them away from the aircraft. All 8 passengers were off the aircraft in under 20 seconds and assembled a good distance away. Both the captain and flight attendant checked the cabin for any remaining passengers and then exited the aircraft. Shortly thereafter; arff arrived and began investigating what was causing the burning odor. Airport operations also arrived and helped arrange transportation for the passengers back to the terminal. Supervisors; maintenance; and other ground personnel also arrived to coordinate. I am very impressed by the professionalism displayed by all crew members during this event. CRM and other crew training played an important part in detecting and managing the event. Everyone walked away safely from what had the potential to be an even more serious situation. Thank you to my crew!callback conversation with reporter revealed the following information: no fire was discovered aboard the aircraft. Reporter stated that investigation revealed the source of the odor was the supplemental air conditioner. It is located within the confines of the pressurized cabin; and is not visible to the crew. The reporter now believes that perhaps the unit had not been utilized since last summer; and the initial startup may have created the odor.

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Original NASA ASRS Text

Title: SAAB340 WAS EVACUATED DURING TAXI-OUT WHEN A STRONG BURNING ODOR WAS DETECTED BY CABIN CREW. SOURCE OF ODOR WAS A SELDOM-USED; CABIN-LOCATED SUPPLEMENTAL AIR CONDITIONER.

Narrative: WE WERE HEADING TO RWY FOR DEPARTURE. THE CAPT AND I WERE COMPLETING THE 'BEFORE TAKEOFF CHECK' WHEN THE THE FA CHIMED US ON THE INTERPHONE AND SAID THERE WAS A STRONG BURNING SMELL IN THE CABIN. I ASKED HER IF SHE COULD SEE ANY SMOKE OR COULD TELL WHERE IT WAS COMING FROM. SHE SAID SHE WOULD CHECK AND CALL US BACK. THE CAPT WAS MONITORING THE INTERPHONE CONVERSATION ON HIS HEADSET AND WE BEGAN DISCUSSING THE SITUATION. WE DECIDED TO PULL OFF THE TAXIWAY UNTIL WE DETERMINED WHAT WAS WRONG. I CALLED ZZZ GROUND AND TOLD THEM THAT WE NEEDED TO PULL OFF THE TAXIWAY. I BELIEVE I SAID IT WAS BECAUSE WE HAD A BURNING ODOR IN THE CABIN BUT CANNOT REMEMBER. WE ALSO DECIDED TO SHUT OFF ALL BLEED AIR AND SUPPLEMENTAL AC AS THAT COULD BE A CAUSE OF THE ODOR. THE CAPT CLOSED THE ENGINE BLEEDS AND I SHUT DOWN THE SUPPLEMENTAL AC. ABOUT THAT SAME TIME THE FA CHIMED US AGAIN AND SAID THE BURNING ODOR WAS GETTING STRONGER AND WORSE. THE CAPT TOLD ME TO CALL GROUND AND TELL THEM ABOUT OUR SITUATION AND REQUEST THE FIRE DEPARTMENT/ARFF AS WELL AS TO PREPARE TO EXIT THE AIRCRAFT. I ATTEMPTED NUMEROUS TIMES TO CONTACT GROUND BUT DUE TO A CONGESTED FREQUENCY DID NOT MAKE CONTACT WITH THEM FOR ABOUT 15 TO 25 SECONDS. WHEN I DID GET THROUGH I TOLD THE CONTROLLER THAT WE WERE SHUTTING DOWN ON THE TAXIWAY AND REQUESTING THE FIRE DEPARTMENT. HE ASKED WHY. I SAID; 'WE HAVE A BURNING ODOR IN THE CABIN.' DURING THIS TIME THE CAPT PROCEEDED TO SHUT DOWN THE AIRCRAFT. AFTER I MADE THE RADIO CALL TO GROUND I TOLD THE CAPT I WAS GOING TO HELP FLT ATTENDANT GET THE PASSENGERS OFF. HE APPROVED OF THE PLAN AND CONTINUED POWERING DOWN THE AIRCRAFT. AS SOON AS I OPENED THE COCKPIT DOOR I WAS IMMEDIATELY HIT WITH THE BURNING SMELL/ODOR. IT SMELLED SIMILAR TO BURNING PLASTIC. I DO NOT RECALL SEEING ANY SMOKE. AS SOON AS THE PROP STOPPED SPINNING I TOLD FLT ATTENDANT TO GO AHEAD AND OPEN THE DOOR AND DROP THE STAIRS. SHE DID AND WE BEGAN A VERY ORDERLY AND EFFICIENT DEPLANING. I SAID SOMETHING ALONG THE LINES OF FOLLOW ME TO THE PASSENGERS AND LED THEM AWAY FROM THE AIRCRAFT. ALL 8 PASSENGERS WERE OFF THE AIRCRAFT IN UNDER 20 SECONDS AND ASSEMBLED A GOOD DISTANCE AWAY. BOTH THE CAPT AND FA CHECKED THE CABIN FOR ANY REMAINING PASSENGERS AND THEN EXITED THE AIRCRAFT. SHORTLY THEREAFTER; ARFF ARRIVED AND BEGAN INVESTIGATING WHAT WAS CAUSING THE BURNING ODOR. AIRPORT OPERATIONS ALSO ARRIVED AND HELPED ARRANGE TRANSPORTATION FOR THE PASSENGERS BACK TO THE TERMINAL. SUPERVISORS; MAINT; AND OTHER GROUND PERSONNEL ALSO ARRIVED TO COORDINATE. I AM VERY IMPRESSED BY THE PROFESSIONALISM DISPLAYED BY ALL CREW MEMBERS DURING THIS EVENT. CRM AND OTHER CREW TRAINING PLAYED AN IMPORTANT PART IN DETECTING AND MANAGING THE EVENT. EVERYONE WALKED AWAY SAFELY FROM WHAT HAD THE POTENTIAL TO BE AN EVEN MORE SERIOUS SITUATION. THANK YOU TO MY CREW!CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: NO FIRE WAS DISCOVERED ABOARD THE ACFT. REPORTER STATED THAT INVESTIGATION REVEALED THE SOURCE OF THE ODOR WAS THE SUPPLEMENTAL AIR CONDITIONER. IT IS LOCATED WITHIN THE CONFINES OF THE PRESSURIZED CABIN; AND IS NOT VISIBLE TO THE CREW. THE REPORTER NOW BELIEVES THAT PERHAPS THE UNIT HAD NOT BEEN UTILIZED SINCE LAST SUMMER; AND THE INITIAL STARTUP MAY HAVE CREATED THE ODOR.

Data retrieved from NASA's ASRS site as of May 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.