"When I close my eyes, I see the oxygen masks dangling in front of me." That's the lingering anxiety of a passenger on a recent Air China flight that plummeted thousands of feet after oxygen levels dropped. A senior official from the Civil Aviation Administration of China tells CNN the reason for the descent stems from a co-pilot smoking an e-cigarette. The official says the pilot tried to shut off air-recycling fans so the vapor wouldn't reach the cabin, but "toggled the wrong switches," causing air pressure to drop. After the plane fell Tuesday during a three-hour flight from Hong Kong to the Chinese city of Dalian, pilots were able to bring the plane back to around 25,000 feet, and it landed safely. Various sources are listing different numbers for how far the plane actually dropped, but flight data cited by Newsweek shows an approximately 21,000-foot decrease over 18 minutes.
Per the South China Morning Post, a couple of the passengers posted pics and video on social media showing people donning the oxygen masks that came down, though the mood was relatively calm. "The announcement from the cockpit said the ability to increase oxygen in the cabin malfunctioned so the plane lost pressure," one wrote on Weibo. Reuters notes that even though China's airlines have a pretty decent safety record, pilots are sometimes accused by passengers of smoking during flights. China bars flight crews from "smoking on all phases of operation," and passengers there haven't been able to use e-cigarettes on planes since 2006. Air China says it will "adopt a zero-tolerance attitude and seriously punish those found responsible," depending on the results of the CAAC's probe. (Read more vaping stories.)