Authorities have determined that an Air China flight’s sudden 21,000-foot descent was caused by a co-pilot smoking an electronic cigarette mid-flight. Chinese investigators announced their findings after the July 10 incident, which occurred aboard Flight CA106 from Hong Kong to Dalian 30.
According to the BBC, the male co-pilot “tried to hide the fact that he was smoking” in the cockpit and attempted to turn off a fan to prevent smoke from reaching the passenger cabin “without telling the captain,” but accidentally turned off the air-conditioning unit instead.
This caused oxygen levels in the cabin to fall and triggered the release of oxygen masks from the cabin ceiling. The pilots were then quickly forced to drop the plane by 21,000 feet, before returning to a safe cruising altitude.
The flight went on to land in Dalian without incident. Officials are reportedly investigating the incident “in greater detail,” reviewing the flight data recorder and the cockpit voice recorder for more information.
Source: ‘Vaping’ pilot caused Air China plane to plunge 6,500m