Shanghai-based COMAC, the company that produces the C919, China's first large passenger plane, will launch function testing of its second homegrown large aircraft soon, which is expected to have its maiden flight in the fourth quarter, official sources said.

The second C919 jetliner, coded 10102, was undergoing assembly testing at the assembly shop of Commercial Aircraft Corp of China Ltd on Wednesday, according to the Xinhua News Agency. Chinanews.com reported that C919's flight tests will include 729 items and may take as long as 4,200 hours.

You Liyan, an official from COMAC's flight test division, said six aircraft will be assigned to undertake different tasks to test the flight performance of the country's first homegrown jets. "Taking the second aircraft for example, it will be tasked to test engine performance," said You.