An emergency descent by an Air China aircraft after cabin oxygen levels dropped has been linked to a co-pilot smoking an e-cigarette during the flight, state media said on Friday.
The state-backed Air China Boeing 737 aircraft was flying to the Chinese city of Dalian from Hong Kong when it went down to 10,000 feet (3,048 m), with oxygen masks deployed. Then it climbed again to continue to its destination, an incident that fuelled the concerns of safety experts.