Plane crash in China: The Boeing aircraft made the same journey at least 66 times this past year

Flight MU5735 took off at 1:11 p.m. local time from Kunming en route to Guangzhou, a trip that this plane had made at least 66 times in the past year.

The crash is the world's deadliest air disaster since a Ukraine International Airlines 737-800 was shot down shortly after take-off from Tehran in January 2020 killing all 176 people on board.

The plane, which the flight tracking service said was six years old, had been cruising at 29,100 feet at 0620 GMT. The same flight number a day earlier began a normal gradual descent from the same altitude, also at 0620 GMT, according to Flightradar24, to land safely in Guangzhou.

The flight that crashed instead began a rapid descent to 7,425 feet before recovering briefly to 8,600 feet and then went into another dive, Flightradar24 data showed. The last tracked altitude was 3,225 feet above sea level.

The aircraft registered B-1791 had flown over a 1,000 flights over the last year. It largely flew domestic routes with its two most frequent flight corridors being between Kunming to Shanghai and Guangzhou. The plane flew between Kunming and Guangzhou 131 times, its second most frequent route according to Flightradar24.

Crashes during the cruise phase of flights are relatively rare, even though this period accounts for the majority of flight time. Crashes during the descent stage when the plane first leaves cruising altitude are even more uncommon.

Boeing said last year 13% of fatal commercial accidents globally between 2011 and 2020 occurred during the cruise phase, whereas 3% occurred on descent, none on initial approach, 28% on final approach and 26% on landing.

China's aviation safety record, while good, is also less transparent than in countries like the United States and Australia where regulators release detailed reports on non-fatal incidents, said Greg Waldron, Asia managing editor at industry publication Flightglobal.

"This makes it hard to get a sense of the true situation with Chinese carriers," he said. "There have been concerns that there is some underreporting of safety lapses on the mainland."

Aircraft accident deaths in China

In the last 40 years, a total of 1,353 people have died in aircraft crashes in China, but its safety record has improved markedly over that time. The last major crash was 12 years ago.

Monday's crash was the most deadly since China's worst ever air disaster in 1994, when a China Northwest Airlines Tupolev Tu-154 flying from Xian to Guangzhou was destroyed in an accident after takeoff, killing all 160 people on board, according to Aviation Safety Network.

The Boeing 737-800 model that crashed on Monday has a strong safety record and is the predecessor to the 737 MAX model that has been grounded in China for more than three years following fatal crashes in 2018 in Indonesia and 2019 in Ethiopia.

Media cited a rescue official as saying the plane had disintegrated on impact. Investigators will be looking to recover the plane's two so-called black boxes – the flight data recorder and cockpit voice recorder – to help shed light on the cause of the crash.

China Eastern and two of its subsidiaries on Monday grounded its fleet of 737-800 planes. The group has 225 of the aircraft, data from British aviation consultancy IBA shows.

Other Chinese carriers are continuing to fly the jets, according to data from Chinese aviation data provider Flight Master.Based on the current information available, authorities do not have a clear assessment of the cause of Monday's crash, Zhu Tao, director of aviation safety at the Civil Aviation Administration of China, told reporters at the first government briefing on the disaster.