Narrative:

At several times during the flight, we thought we detected a faint, unidentifiable odor. At approximately 37n175e, the odor became strong enough to try to locate the source, which was determined to be the forward part of the cockpit. We turned off the vents and the foot and shoulder heaters to try to eliminate them as possible sources. Very shortly after turning off these items, there was a bright spark at the bottom left corner of the forward left window. A small flame, a few inches high, appeared immediately after the spark. The captain applied 1 very brief burst from the cockpit fire extinguisher and the flame was instantly eliminated. We then accomplished the checklist for 'window heat l-r forward.' tactile examination confirmed that the backup window heat was functioning normally. Callback conversation with reporter revealed the following information: the reporter stated the sparking was at the lower left corner of the forward windshield at the connection of the 2 wires supplying power to the windshield. The reporter said 1 wire terminal was loose and shorted to the adjacent wire. The reporter stated no circuit breakers were found tripped when checked on the ground. The reporter said the circuit breakers are located in the lower electronics compartment. The reporter stated no emergency was declared as the fire was out and the power switch was in 'off' position and the backup window heat was functioning. The reporter said the crew was debriefed by technical representative, FAA and maintenance.

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Original NASA ASRS Text

Title: A B777 IN CRUISE AT FL350 EXPERIENCED SPARKING AND 4 INCH FLAME AT THE L FORWARD WINDSHIELD, L LOWER EDGE BUS BAR CONNECTION, AND WIRING.

Narrative: AT SEVERAL TIMES DURING THE FLT, WE THOUGHT WE DETECTED A FAINT, UNIDENTIFIABLE ODOR. AT APPROX 37N175E, THE ODOR BECAME STRONG ENOUGH TO TRY TO LOCATE THE SOURCE, WHICH WAS DETERMINED TO BE THE FORWARD PART OF THE COCKPIT. WE TURNED OFF THE VENTS AND THE FOOT AND SHOULDER HEATERS TO TRY TO ELIMINATE THEM AS POSSIBLE SOURCES. VERY SHORTLY AFTER TURNING OFF THESE ITEMS, THERE WAS A BRIGHT SPARK AT THE BOTTOM L CORNER OF THE FORWARD L WINDOW. A SMALL FLAME, A FEW INCHES HIGH, APPEARED IMMEDIATELY AFTER THE SPARK. THE CAPT APPLIED 1 VERY BRIEF BURST FROM THE COCKPIT FIRE EXTINGUISHER AND THE FLAME WAS INSTANTLY ELIMINATED. WE THEN ACCOMPLISHED THE CHKLIST FOR 'WINDOW HEAT L-R FORWARD.' TACTILE EXAMINATION CONFIRMED THAT THE BACKUP WINDOW HEAT WAS FUNCTIONING NORMALLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE SPARKING WAS AT THE LOWER L CORNER OF THE FORWARD WINDSHIELD AT THE CONNECTION OF THE 2 WIRES SUPPLYING PWR TO THE WINDSHIELD. THE RPTR SAID 1 WIRE TERMINAL WAS LOOSE AND SHORTED TO THE ADJACENT WIRE. THE RPTR STATED NO CIRCUIT BREAKERS WERE FOUND TRIPPED WHEN CHKED ON THE GND. THE RPTR SAID THE CIRCUIT BREAKERS ARE LOCATED IN THE LOWER ELECTRONICS COMPARTMENT. THE RPTR STATED NO EMER WAS DECLARED AS THE FIRE WAS OUT AND THE PWR SWITCH WAS IN 'OFF' POS AND THE BACKUP WINDOW HEAT WAS FUNCTIONING. THE RPTR SAID THE CREW WAS DEBRIEFED BY TECHNICAL REPRESENTATIVE, FAA AND MAINT.

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.