B-KPQ, a Cathay Pacific Boeing 777-367ER, was operating as CPA865D from Vancouver Intl (CYVR), BC to Chek Lap Kok Intl (VHHH), Hong Kong with 18 crew and no passengers on board. As the aircraft leveled at FL 320 , the crew detected smoke in the cockpit and the cabin. The crew
declared an emergency and requested a return to CYVR. The aircraft dumped fuel to 84 000 kg 40 NM NW of CYVR. The aircraft landed without further incident a approximately 11 000 kg over the maximum landing weight. ARFF was standing by.
Maintenance conducted an overweight landing inspection with no faults found. They verified that the smoke was in fact oil fumes/haze caused by an oil contaminated air conditioning system. They traced the origin of the oil source to the aircraft’s APU. Numerous components of the air
conditioning system were replaced and the ducting was removed and cleaned.
The APU was deactivated for the return flight to VHHH and the aircraft has returned to service.