BEIJING (AFP, REUTERS) - China Eastern Airlines has restarted using Boeing 737-800 jetliners for commercial flights less than a month after a crash that killed 132 people on board and grounded over 200 of its aircraft, data from a tracking website showed on Sunday (April 17).

China Eastern flight MU5843, operated by a three-year-old Boeing 737-800 aircraft, took off from the south-western city of Kunming at 9.58am local time on Sunday and landed at Chengdu, also in south-western China, at 11.03am local time, data from Flightradar24 showed.

That aircraft, which completed a test flight on Saturday, departed Chengdu at 1.02pm for Kunming, according to Flightradar24.

Another Boeing 737-800 jet conducted a test flight on Sunday morning in Shanghai, where China Eastern is based, Flightradar24 data showed.

China Eastern was not immediately available for comment.

On March 21, Flight MU5735, which was en route from Kunming to Guangzhou, crashed in the mountains of Guangxi and killed 123 passengers and nine crew members in mainland China's deadliest aviation disaster in 28 years.

The cause of the disaster is not yet known.

The incident caused China Eastern to ground all of its Boeing 737-800 series aircraft for safety checks, as aviation authorities vowed an extensive two-week inspection of the country’s vast passenger fleet.

It was a major setback for the return of Boeing’s 737 MAX to China, the last big market where the American plane maker is still awaiting approval to fly following crashes in Indonesia and Ethiopia that killed a combined 346 people in 2018 and 2019.

China has retrieved both of the black boxes  from its downed jet, which are currently being analysed at an American lab with the help of investigators from the United States government.

Beijing has said it would submit a preliminary report to the United Nations aviation agency ICAO within 30 days of the event.