An Air China flight suddenly lost air pressure and dropped 6,000 meters (19,600 feet) because the pilots were allegedly smoking in the cockpit and pushed the wrong buttons.
The Boeing 737 jet liner was on its way back from Honk Kong to the north-eastern Chinese city of Dalian, carrying 153 passengers and nine crew members.
The plane safely landed in Dalian; however, the sudden descent from above 10,000 meters (32,800 feet) to below 4,000 meters (13,100 feet) in less than nine minutes has prompted an investigation into the incident.
Chinese state media has accused the pilots of violating civil aviation rules and smoking in the cockpit. According to reports, the loss in cabin pressure, which resulted in oxygen masks being drawn out for passengers, and the sudden descent, was caused when the pilots mistook two switches for air recycling fans and switched them off.
"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) investigating the incident.
"Smoke diffused into the passenger cabin and relevant air conditioning components were wrongly shut off, without notifying the captain, which resulted in insufficient oxygen," it added.
The error was later corrected and the jet liner climbed back to around 7,500 meters (24,600 feet), flying to Dalian with less-than-adequate oxygen.
Air China also came forward with a statement regarding the incident and said if the allegations prove to be true, the airline will adopt a “zero-tolerance policy” and “seriously punish” those responsible.
A CAAC regulator added the investigators have interviewed crew members and the black box — the flight data and cockpit voice recorder — has been sent for decoding.
Hoby Sun, a passenger on the flight, told CNN everyone was calm when the oxygen masks dropped.
“I didn't think too much of it at the time -- we didn't know what was going on, nor did the flight attendants it seemed,” he said. “I'm not physically hurt, but the psychological impact lingers. When I close my eyes, I see the oxygen masks dangling in front of me.”
Banner / Thumbnail : REUTERS, Regis Duvignau