Vaping co-pilot caused Air China plane to plummet, officials say

Hoby Sun was on board the Air China flight when it suddenly lost pressure and altitude.

Beijing (CNN)A co-pilot smoking an electronic cigarette in the cockpit of an Air China flight caused the plane to suddenly drop 6,000 meters (19,600 feet) when he mistakenly turned off its air conditioning system.

A senior official from the Civil Aviation Administration of China (CAAC) told reporters Friday that, without notifying the pilot, the unnamed co-pilot was trying to turn off air recycling fans to prevent the vapor from spreading into the passenger cabin.
Instead, he toggled the wrong switches, which were close to his intended target, leading to a drop in oxygen levels that triggered altitude warnings.
Qiao Yibin, the CAAC official, promised to hand down "severe punishment in accordance with laws and regulations," if the regulator's final conclusion on the incident matches its initial finding.
    Air China fired the entire flight deck crew and suggested CAAC revoke their pilot's licenses upon completing its investigation, the country's flag carrier said Friday night in a statement.
    Why oxygen masks are released on planes

    Planes fly at high altitudes, where the air is very thin.

    To allow passengers to breathe normally, cabins are pressurized. If a plane loses pressure rapidly, the air can become difficult to breathe, and passengers might suffer from hypoxia -- a dangerous lack of oxygen.

    To prevent this, oxygen masks fall from the ceiling, and pilots will attempt to bring the plane below 3,000 meters (10,000 feet), where supplementary oxygen is no longer needed.

    Source: Australian Transport Safety Bureau

    Air China flight CA106, en route from Hong Kong to the northeastern Chinese city of Dalian, descended from above 10,000 meters (32,800 feet) to below 4,000 meters (13,100 feet) in less than nine minutes Tuesday shortly after it reached cruising altitude, according to phone GPS data shared with CNN by a passenger on board.
    The Boeing 737 jetliner was carrying 153 passengers and nine crew members on the three-hour journey and landed safely in Dalian, CAAC said Thursday.
    Citing anonymous industry sources, multiple Chinese state media outlets had reported earlier that, after the abrupt drop in altitude, the plane eventually climbed back to around 7,500 meters (24,600 feet) and flew to its destinat