China's aviation authorities on Friday started to allow helicopters to fly in low-altitude airspace over the tourist island of Hainan on a trial basis for the first time. The aim is to eventually open a part of the country's tightly-controlled airspace to private aircraft.

Four helicopters were manned by eight pilots from Shanghai-based Zhengyang Investment Group, a leading domestic firm in the general aviation industry. They are expected to conduct test flights in the sky, 1,000 meters above the ground in Hainan in the next two months.

The flight test will collect data for low-altitude flying and test the ground control system's response to emergencies, said Zou Jianming, chairman of Zhengyang Investment Group.

Hainan is the first place in China to conduct test flights of private aircraft in low-altitude airspace, said Jiang Sixian, deputy governor of the province. Domestic and foreign firms are both welcome to invest in Hainan's general aviation sector to develop world-class tourism here.

China's low-altitude airspace is controlled by the Air Force and the Civil Aviation Administration of China (CAAC). Every private aircraft flight needs approval, and the procedure can take from one day up to a week.

But last November, the State Council and the Central Military Commission said that part of the low-altitude airspace would be opened to promote the country's general aviation sector, including the purchase and use of private planes.

General aviation refers to the part of the aviation industry that excludes flights for military, law enforcement and public transport. China has only 900 aircraft, 80 airports and fewer than 10,000 pilots in the general aviation segment.

The market for general aviation in China is valued at only 13 billion yuan (1.98 billion U.S. dollars) but is expected to grow by 15 percent annually until 2020, Hainan aviation officials said.