Narrative:

Smoke was seen rapidly emitting from the cockpit instrument panel near the TCASII monitor. Emergency procedures and checklists were conducted including declaration of emergency to gander radio. Track deviation accomplished in order to divert to gander. During en route segment to gander; malfunction and shutdown of TCASII monitor occurred followed by ending of smoke. Transponder/TCASII devices were placed in the 'off' position and associated circuit breakers were pulled. Conducted overweight landing without further incident. Supplemental information from acn 650113: smoke in cockpit lasting approximately 10-15 seconds. Smoke seemed to emanate from the TCASII display unit and smelled electrical in nature. Suggested to captain we both don our oxygen masks; that I would run the checklist while he might want to consider an immediate left turn to the 30 mi offset from our current oceanic track 'west.' further suggested we get first officer back on the flight deck from his break. First officer seemed to appear in the cockpit within 2 mins. First officer immediately smelled the smoke fumes and noticed the TCASII display unit was blank. I suggested he take his first officer seat back. First officer immediately declared an emergency on 121.5 and with gander radio on HF while requesting clearance to return to gander. Captain had the aircraft established on a 30 mi offset to the north of track 'west' just about the time we were receiving an emergency divert clearance from gander oceanic via gander radio on HF. All 3 pilots agreed we should turn off the TCASII function on the radio on transponder/TCASII unit. I further suggested and was instructed to pull both the TCASII and TCASII indicator display circuit breakers and as a precaution both left and right ATC transponder circuit breakers. I ran the cockpit smoke and fumes removal abnormal procedure and briefed the purser to advise the flight attendants to avoid any strenuous activity as I would be raising the cabin altitude to 9500 ft per the checklist. Landed in gander slightly after XA00Z; 3500 pounds overweight at 313500 pounds.

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Original NASA ASRS Text

Title: A B767-300ER'S TCASII DISPLAY EXPERIENCED AN ELECTRICAL MALFUNCTION CAUSING COCKPIT SMOKE. THE CREW DIVERTED OFF A TRANSATLANTIC RTE.

Narrative: SMOKE WAS SEEN RAPIDLY EMITTING FROM THE COCKPIT INST PANEL NEAR THE TCASII MONITOR. EMER PROCS AND CHKLISTS WERE CONDUCTED INCLUDING DECLARATION OF EMER TO GANDER RADIO. TRACK DEV ACCOMPLISHED IN ORDER TO DIVERT TO GANDER. DURING ENRTE SEGMENT TO GANDER; MALFUNCTION AND SHUTDOWN OF TCASII MONITOR OCCURRED FOLLOWED BY ENDING OF SMOKE. XPONDER/TCASII DEVICES WERE PLACED IN THE 'OFF' POS AND ASSOCIATED CIRCUIT BREAKERS WERE PULLED. CONDUCTED OVERWT LNDG WITHOUT FURTHER INCIDENT. SUPPLEMENTAL INFO FROM ACN 650113: SMOKE IN COCKPIT LASTING APPROX 10-15 SECONDS. SMOKE SEEMED TO EMANATE FROM THE TCASII DISPLAY UNIT AND SMELLED ELECTRICAL IN NATURE. SUGGESTED TO CAPT WE BOTH DON OUR OXYGEN MASKS; THAT I WOULD RUN THE CHKLIST WHILE HE MIGHT WANT TO CONSIDER AN IMMEDIATE L TURN TO THE 30 MI OFFSET FROM OUR CURRENT OCEANIC TRACK 'W.' FURTHER SUGGESTED WE GET FO BACK ON THE FLT DECK FROM HIS BREAK. FO SEEMED TO APPEAR IN THE COCKPIT WITHIN 2 MINS. FO IMMEDIATELY SMELLED THE SMOKE FUMES AND NOTICED THE TCASII DISPLAY UNIT WAS BLANK. I SUGGESTED HE TAKE HIS FO SEAT BACK. FO IMMEDIATELY DECLARED AN EMER ON 121.5 AND WITH GANDER RADIO ON HF WHILE REQUESTING CLRNC TO RETURN TO GANDER. CAPT HAD THE ACFT ESTABLISHED ON A 30 MI OFFSET TO THE N OF TRACK 'W' JUST ABOUT THE TIME WE WERE RECEIVING AN EMER DIVERT CLRNC FROM GANDER OCEANIC VIA GANDER RADIO ON HF. ALL 3 PLTS AGREED WE SHOULD TURN OFF THE TCASII FUNCTION ON THE RADIO ON XPONDER/TCASII UNIT. I FURTHER SUGGESTED AND WAS INSTRUCTED TO PULL BOTH THE TCASII AND TCASII INDICATOR DISPLAY CIRCUIT BREAKERS AND AS A PRECAUTION BOTH L AND R ATC XPONDER CIRCUIT BREAKERS. I RAN THE COCKPIT SMOKE AND FUMES REMOVAL ABNORMAL PROC AND BRIEFED THE PURSER TO ADVISE THE FLT ATTENDANTS TO AVOID ANY STRENUOUS ACTIVITY AS I WOULD BE RAISING THE CABIN ALT TO 9500 FT PER THE CHKLIST. LANDED IN GANDER SLIGHTLY AFTER XA00Z; 3500 LBS OVERWT AT 313500 LBS.

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.