On Tuesday, a co-pilot for Air China ignored the rule banning smoking on commercial passenger flights and enjoyed an e-cigarette in the cockpit, but the passengers didn’t enjoy what happened next: the plane plummeted at least 20,000 feet.
According to the Civil Aviation Administration of China (CAAC), the flight was traveling from Hong Kong to the city of Dalian in northeastern China when the co-pilot turned off a ventilation system so the smoke from his e-cigarette would not travel into the main cabin. But he switched off the air-conditioning instead, triggering a decrease in cabin oxygen levels. That, in turn, catalyzed the emergency warning system to show the 737 jet may have flown too high; the warning system told the pilots to descend rapidly.
As The Daily Mail reports, “The CAAC said the aircraft dropped down to as low as 3,000 metres (10,000 feet), without specifying its original altitude. According to FlightRadar24 it descended from 35,000 feet to 10,000 feet in 10 minutes as is standard practice in a decompression event. It then ascended and continued the flight at a peak altitude of 26,600 feet rather than heading to a nearby airport to land.”
According to some airline experts, who noted that oxygen masks were deployed for the 153 passengers, standard procedure calls for the plane to continue to descend and land. They noted that another decompression event could occur after 12-20 minutes of oxygen had been utilized. Former Qantas head of safety Ron Bartsch said, “The crew would not have been able to accurately assess the amount of emergency oxygen available. In my opinion the pilot in command should have landed at the nearest suitable airport.”
The BBC, which said the plane dropped roughly 20,000 feet, noted, “Chinese flight regulations prohibit all flight crew from smoking, and banned passengers from using e-cigarettes on board in 2006. But there have been accusations of pilots smoking on board other Chinese flights, including in 2015 when the state-run radio spoke to passengers on a Hong Kong-Beijing flight who claimed to smell strong smoke coming from the cockpit.”