Sichuan Airlines Airbus's co-pilot was sucked halfway after a cockpit windshield blew out forcing an emergency landing.
The co-pilot was cut on the face and suffered an injury to the lower back.
"As pilots we receive such training twice a year, but it was one thing to train on a simulator and another when you are affected by the sudden loss of pressure and oxygen when the temperature drops to minus 40 degrees".
Captain Liu Chuanjian told Chengdu Business Daily that the incident caused his co-pilot to be partially sucked out of the window.
Mr Chuanjian, who was hailed a hero after landing the Airbus A319 manually in China, said: 'There was no warning sign.
Sichuan Airlines reported on its Weibo account that an aircraft had suffered a "mechanical failure".
The flight, Sichuan Airlines 3U8633, left the central Chinese municipality of Chongqing on Monday morning and was bound for the Tibetan capital of Lhasa, the authority said. The plane landed in Chengdu at 7:46 am today.
Incidents involving cracked windshields do happen on a regular basis due to occurrences such as bird or lightning strikes but ones involving entire windshields coming off are rare.
Pictures published by government-run Chengdu Economic Daily showed the plane missing one of its cockpit windows and damage to its cockpit controls.
The video, filmed in Flight 3U8633 from Chongqing to Lhasa on May 14, shows passengers using oxygen masks and a flight attendant saying: "Those exits can not be opened" and "Be safe".
The cockpit window fell out mid-flight and the plane was forced to make an emergency landing at a nearby airport.
None of the plane's 119 passengers were injured.
Twenty-seven passengers received medical checkups in a hospital in Chengdu, but no injuries were detected. Most of the equipment malfunctioned. and I couldn't hear the radio.
"The sudden loss of pressure and low temperature made me very uncomfortable and it was very hard to make a single move when the aircraft was flying at 900 kilometres an hour and at such a high altitude", Liu said. He says he felt the cold air and saw how the cockpit door opened. This incident is very unusual and only further investigation will lead to a resolution, Zhang added.