Narrative:

We smelled smoke in the cockpit for several minutes with no abnormal indications from instrumentation or visual sign of smoke. We then noticed the IRS 'batt warn' light illuminated on the overhead panel. I opened the hatch to the lower electronic bay and could detect no sign of smoke below either. Shortly after that the co-pilot hollered 'fire' 'fire.' I looked up at his side of the cockpit and saw flames licking up over the track of his sliding window. He could see that the fire was coming from the flexible power cord supplying electricity to the defog system on his sliding glass window. He turned off the switch supplying power to the window as I was getting out of my seat to extinguish the flame. With power removed from the window the fire continued to burn. Since it was not an arcing fire I threw water from my water bottle on the flame and put it out. We pulled the circuit breaker for the equipment involved, declared an emergency and landed at ZZZ1. Callback conversation with reporter revealed the following information: the reporter stated for a short period of time a smoke odor was present in the cockpit, but the source was undetectable. The reporter said when the first officer shouted 'fire' 'fire' he observed thumb size flames from the flexible cord supplying power to the first officer's sliding window. The reporter said at no time did a circuit breaker for the window defog or window heat trip. The reporter stated the breakers were tripped manually. The reporter said on the ground, when maintenance opened the panel exposing the flexible cord terminal strip, it was noted the kapton wire supplying the power to the flexible cord showed no signs of overheating. Supplemental information from acn 592495: on flight from bos to ZZZZ had an odor in cockpit at FL350. Same time had a 'batt warn' light on #2 inertial navigation unit panel. He stood to get book from library because 'batt warn' light was not in quick reference handbook. At that time I saw the insulation to right side sliding window was burning with 3-4 in flames. I immediately put on my mask and turned off right side window heat. I don't think we could have prevented this problem. We were distracted by unrelated 'batt warn' light. I'm thankful fire was in element easy to see and determine the source of power. Disturbing is why the circuit breaker did not trip! Callback conversation with reporter acn 592495 revealed the following information: reporter stated that the airbus 310 has had problems with the wiring that supplies the side window for the window heat. It is not a problem in the air carrier's A300's, but ongoing in the A310. He noted that company put out a safety bulletin to all pilots reporting that company maintenance is researching a solution to the wiring problem and to be aware that the wires do fray. The wires drag along the side of the cockpit and the insulation becomes bare. Additionally, the reporter noted that the circuit breakers did not trip during the event and he located them and pulled the circuit breaker as the other pilot extinguished the flames. The wire is a coiled, flexible wire similar to the wire on the handset of a telephone, only much more robust.

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Original NASA ASRS Text

Title: AN AIRBUS 310 IN CRUISE AT FL 350 DECLARED AN EMER AND DIVERTED DUE TO SMOKE AND FIRE IN THE COCKPIT. CAUSED BY WINDOW HEAT FLEXIBLE PWR CORD.

Narrative: WE SMELLED SMOKE IN THE COCKPIT FOR SEVERAL MINUTES WITH NO ABNORMAL INDICATIONS FROM INSTRUMENTATION OR VISUAL SIGN OF SMOKE. WE THEN NOTICED THE IRS 'BATT WARN' LIGHT ILLUMINATED ON THE OVERHEAD PANEL. I OPENED THE HATCH TO THE LOWER ELECTRONIC BAY AND COULD DETECT NO SIGN OF SMOKE BELOW EITHER. SHORTLY AFTER THAT THE CO-PLT HOLLERED 'FIRE' 'FIRE.' I LOOKED UP AT HIS SIDE OF THE COCKPIT AND SAW FLAMES LICKING UP OVER THE TRACK OF HIS SLIDING WINDOW. HE COULD SEE THAT THE FIRE WAS COMING FROM THE FLEXIBLE POWER CORD SUPPLYING ELECTRICITY TO THE DEFOG SYSTEM ON HIS SLIDING GLASS WINDOW. HE TURNED OFF THE SWITCH SUPPLYING PWR TO THE WINDOW AS I WAS GETTING OUT OF MY SEAT TO EXTINGUISH THE FLAME. WITH PWR REMOVED FROM THE WINDOW THE FIRE CONTINUED TO BURN. SINCE IT WAS NOT AN ARCING FIRE I THREW WATER FROM MY WATER BOTTLE ON THE FLAME AND PUT IT OUT. WE PULLED THE CIRCUIT BREAKER FOR THE EQUIPMENT INVOLVED, DECLARED AN EMER AND LANDED AT ZZZ1. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED FOR A SHORT PERIOD OF TIME A SMOKE ODOR WAS PRESENT IN THE COCKPIT, BUT THE SOURCE WAS UNDETECTABLE. THE RPTR SAID WHEN THE FIRST OFFICER SHOUTED 'FIRE' 'FIRE' HE OBSERVED THUMB SIZE FLAMES FROM THE FLEXIBLE CORD SUPPLYING PWR TO THE FO'S SLIDING WINDOW. THE RPTR SAID AT NO TIME DID A CIRCUIT BREAKER FOR THE WINDOW DEFOG OR WINDOW HEAT TRIP. THE RPTR STATED THE BREAKERS WERE TRIPPED MANUALLY. THE RPTR SAID ON THE GND, WHEN MAINT OPENED THE PANEL EXPOSING THE FLEXIBLE CORD TERMINAL STRIP, IT WAS NOTED THE KAPTON WIRE SUPPLYING THE PWR TO THE FLEXIBLE CORD SHOWED NO SIGNS OF OVERHEATING. SUPPLEMENTAL INFO FROM ACN 592495: ON FLT FROM BOS TO ZZZZ HAD AN ODOR IN COCKPIT AT FL350. SAME TIME HAD A 'BATT WARN' LIGHT ON #2 INERTIAL NAVIGATION UNIT PANEL. HE STOOD TO GET BOOK FROM LIBRARY BECAUSE 'BATT WARN' LIGHT WAS NOT IN QUICK REFERENCE HANDBOOK. AT THAT TIME I SAW THE INSULATION TO R SIDE SLIDING WINDOW WAS BURNING WITH 3-4 IN FLAMES. I IMMEDIATELY PUT ON MY MASK AND TURNED OFF R SIDE WINDOW HEAT. I DON'T THINK WE COULD HAVE PREVENTED THIS PROB. WE WERE DISTRACTED BY UNRELATED 'BATT WARN' LIGHT. I'M THANKFUL FIRE WAS IN ELEMENT EASY TO SEE AND DETERMINE THE SOURCE OF POWER. DISTURBING IS WHY THE CIRCUIT BREAKER DID NOT TRIP! CALLBACK CONVERSATION WITH RPTR ACN 592495 REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE AIRBUS 310 HAS HAD PROBS WITH THE WIRING THAT SUPPLIES THE SIDE WINDOW FOR THE WINDOW HEAT. IT IS NOT A PROB IN THE ACR'S A300'S, BUT ONGOING IN THE A310. HE NOTED THAT COMPANY PUT OUT A SAFETY BULLETIN TO ALL PLTS RPTING THAT COMPANY MAINT IS RESEARCHING A SOLUTION TO THE WIRING PROB AND TO BE AWARE THAT THE WIRES DO FRAY. THE WIRES DRAG ALONG THE SIDE OF THE COCKPIT AND THE INSULATION BECOMES BARE. ADDITIONALLY, THE RPTR NOTED THAT THE CIRCUIT BREAKERS DID NOT TRIP DURING THE EVENT AND HE LOCATED THEM AND PULLED THE CB AS THE OTHER PLT EXTINGUISHED THE FLAMES. THE WIRE IS A COILED, FLEXIBLE WIRE SIMILAR TO THE WIRE ON THE HANDSET OF A TELEPHONE, ONLY MUCH MORE ROBUST.

Data retrieved from NASA's ASRS site as of July 2007 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.