On 25 February 2008, at about 2128 Eastern Daylight-saving Time,
the flight crew of a Boeing Company 747-338 (747) aircraft,
registered VH-EBY, detected a smell that slowly increased in
intensity. At that time, the aircraft was cruising at 37,000 ft and
was about 275 km west south-west of Sydney, NSW.
The flight crew donned their emergency oxygen equipment and
transmitted a PAN call to air traffic control. The aircraft was
cleared direct to Sydney for landing and was escorted to the
terminal by the airport fire services for disembarkation.
An inspection by the operator determined that loose terminal
connections to the left windshield heat element resulted in
electrical arcing and fumes on the flight deck.
The aircraft manufacturer has a programme to replace the
windshields in the 747 with an enhanced windshield heater wiring
connection that should address the risk of electrical arcing in