Dhaka: China Southern Airlines, one of China’s biggest carriers, successfully completed a test flight of the Boeing 737 MAX on January 21, as Chinese airlines prepare for the model's return to service.

The Civil Aviation Administration of China was the first regulator worldwide to ground the 737 MAX following two fatal accidents. But after two and a half years, they approved design changes in early December for the aircraft.

CAAC had expected airlines to resume commercial flights by the aircraft by early 2022.

Earlier, a MAX 8 of China Southern, the largest 737 MAX operator in China, took off from its headquarters city in Guangzhou and landed three hours and 33 minutes later in the same city, according to reports, but without any passengers.

That followed a Hainan Airlines flight on January 9 from Taiyuan, where some of the grounded 737 MAX of the airline were parked, to its base city in Haikou. That flight lasted for two hours and 52 minutes, reports added.

Before MAX was grounded Chinese buyers were its largest customers as Boeing was selling a quarter of the planes it built annually to them.

CAAC officials earlier said the aircraft would need to be modified and pilots would require additional training before they resume commercial flights in the country with MAX.