Narrative:

At FL340 heavy smoke erupted from captain's gasper vent. Fire was observed in the lower left corner of the left forward windscreen. Donned oxygen masks and declared an emergency. Initiated descent then began turn towards ZZZ. During descent; turned off cockpit window heat and used cockpit halon fire extinguisher to extinguish the fire. Smoke began clearing and the fire remained extinguished. Received radar vectors to ZZZ; runway 9; and landed without incidence. Only problem noted was pilot had to leave control seat to reach fire extinguisher and oxygen hose limited movement. Recommend moving fire extinguisher to more accessible location.callback conversation with reporter revealed the following information: the reporter stated when the smoke came out of the captain's gasper vent; it was impossible to pinpoint the overheat or fire and then the flame became visible; as the external wiring to the captain's windshield in the lower left corner was burning. The reporter indicated the windshield heat was turned off and the halon bottle was used to extinguish the fire. The reporter stated that when the captain left the seat to secure the fire bottle; his movements were restricted by the oxygen hose; and suggested moving the fire bottle closer to the crew seats might be a good idea.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B757-200 IN CRUISE AT FL390 EXPERIENCED HVY SMOKE AND FLAME FROM WIRING ON THE LOWER L CORNER OF THE CAPT'S WINDSHIELD. FO RPTS THAT THE CREW DECLARED AN EMER AND DONNED OXYGEN MASKS; BUT THAT THE CAPT'S RETRIEVAL OF THE FIRE EXTINGUISHER WAS RESTRICTED BY THE MASK HOSE AND EXTINGUISHER LOCATION.

Narrative: AT FL340 HVY SMOKE ERUPTED FROM CAPT'S GASPER VENT. FIRE WAS OBSERVED IN THE LOWER L CORNER OF THE L FORWARD WINDSCREEN. DONNED OXYGEN MASKS AND DECLARED AN EMER. INITIATED DSCNT THEN BEGAN TURN TOWARDS ZZZ. DURING DSCNT; TURNED OFF COCKPIT WINDOW HEAT AND USED COCKPIT HALON FIRE EXTINGUISHER TO EXTINGUISH THE FIRE. SMOKE BEGAN CLEARING AND THE FIRE REMAINED EXTINGUISHED. RECEIVED RADAR VECTORS TO ZZZ; RWY 9; AND LANDED WITHOUT INCIDENCE. ONLY PROBLEM NOTED WAS PLT HAD TO LEAVE CTL SEAT TO REACH FIRE EXTINGUISHER AND OXYGEN HOSE LIMITED MOVEMENT. RECOMMEND MOVING FIRE EXTINGUISHER TO MORE ACCESSIBLE LOCATION.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED WHEN THE SMOKE CAME OUT OF THE CAPT'S GASPER VENT; IT WAS IMPOSSIBLE TO PINPOINT THE OVERHEAT OR FIRE AND THEN THE FLAME BECAME VISIBLE; AS THE EXTERNAL WIRING TO THE CAPT'S WINDSHIELD IN THE LOWER L CORNER WAS BURNING. THE RPTR INDICATED THE WINDSHIELD HEAT WAS TURNED OFF AND THE HALON BOTTLE WAS USED TO EXTINGUISH THE FIRE. THE RPTR STATED THAT WHEN THE CAPT LEFT THE SEAT TO SECURE THE FIRE BOTTLE; HIS MOVEMENTS WERE RESTRICTED BY THE OXYGEN HOSE; AND SUGGESTED MOVING THE FIRE BOTTLE CLOSER TO THE CREW SEATS MIGHT BE A GOOD IDEA.

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.