The man accidentally turned off the air conditioner, because of what on board the level of oxygen fell.
The second pilot of the flight Hong Kong – Dalian Airlines AirChina tried to conceal the smoking of an electronic cigarette. He accidentally turned off the air conditioning, because of what the oxygen level in the plane fell and the pilots had to start the emergency descent. This was reported by the BBC.
The aircraft dropped more than 6.5 kilometers, and oxygen masks fell out in the cabin. The pilots were able to bring him back to cruising altitude (for passenger aircraft is an average of 9-12 thousand meters). According to The Sun, the decline occurred in about 10 minutes. After the incident, the airline canceled some flights.
Passengers published photos from the flight in the Chinese social network Weibo. They said that they were asked to fasten their seat belts, since the plane had to land.
According to the authorities, the crew had to take extraordinary measures and throw out oxygen masks for a while, until they solve the problem. If the air pressure drops, the pilots must lower the altitude in order to maintain the safety of the crew and passengers. When the pilots noticed that the air conditioner was off, they turned it on and again gained the necessary height.
The authorities specify the details of the incident, they requested information about the flight and also recordings from the cabins to pinpoint the cause of the incident. According to The Sun, the airline said that the pilots “will not show tolerance” if their fault is proven.