Air China Flight CA106 descended to 10,000 feet (3,048 m), with oxygen masks deployed.
The incident an emergency descent after cabin oxygen levels dropped has been linked to a co-pilot smoking an e-cigarette during the flight. The Boeing 737 was flying to the Chinese city of Dalian from Hong Kong.
“In the preliminary investigation, the co-pilot was found to be smoking an e-cigarette.” state-owned China News said. Citing a news conference by the Civil Aviation Administration of China (CAAC).
“Smoke diffused into the passenger cabin and relevant air conditioning components were wrongly shut off, without notifying the captain, which resulted in insufficient oxygen,” Qiao Yibin, an official of the regulator’s aviation safety office, as saying. China News also stated the co-pilot switched off the air conditioning units. Firstly this triggered a cabin altitude alarm which means oxygen levels in the aircraft where too low. Which prompted the crew to being and emergency descent procedure. The aircraft descended to 10,000ft losing 25,000ft in 10 minutes a rate of 2,500 feet per minute. The crew realized the problem after the descent restored the air conditioning, allowing cabin pressure to return to normal. The flight then climbed back to cruising altitude and completed the flight.
Air China did not immediately respond to requests for comment. It vowed a “zero tolerance” approach towards wrongdoing by any crew, on its official account on China’s Twitter-like Weibo on Wednesday. This isn’t the first time Air China has received complaints about pilots smoking during flights.