On 15 November 2010, a Boeing Company 747‑438 aircraft, registered VH-OEI, departed Sydney, New South Wales on a scheduled passenger service to Buenos Aires, Argentina.
While on climb, the flight crew noticed a strong electrical smell in the cockpit, followed by smoke emanating from the left electronic flight instrument system (EFIS) control panel. The flight crew donned their oxygen masks and shortly after, observed that the circuit breaker for the left EFIS control panel had tripped and the engine indication and crew alerting system (EICAS) was displaying the message 'EFIS CONTROL L'.
About 7 minutes later, the flight crew reported that the fumes were still present and were very strong, despite the fact that the smoke had ceased. After discussing the situation, the flight crew elected to return to Sydney.
During the return, a fuel dump was commenced and a descent to 10,000 ft initiated. During the descent, the flight crew determined that the fumes had stabilised but elected to remain on oxygen as a precaution.
After landing at Sydney, the left EFIS control panel was inspected and replaced.
This incident affirms the importance of using supplemental breathing equipment as a defence against pilot incapacitation from exposure to fumes and smoke.