UPDATE 1-China's COMAC says C919 jet takes 2nd test flight

* C919 first flew on May 5 after years of delays

* Symbol of China's ambitions to compete with Airbus, Boeing

* Local media says plane took off at 7:20 a.m. local time (Updates with details on flight time in last par)

SHANGHAI, Sept 28 (Reuters) - China's self-developed C919 jet has taken off for its second test flight, 146 days after the narrow-body plane made its maiden voyage, the Commercial Aircraft Corp of China (COMAC) said on Thursday.

The aircraft, which will compete with Boeing's 737 and the Airbus A320, is a symbol of China's ambitions to muscle into a global jet market estimated to be worth $2 trillion over the next 20 years. It first flew on May 5 after numerous delays.

News of the plane's flight from Shanghai was first reported by state media including the People's Daily newspaper. A spokesman for COMAC confirmed that the C919 was taking its second flight.

State-backed news website ThePaper.cn said the C919 took off from Shanghai's Pudong Airport at 7:20 a.m. (2320 GMT) and is expected to turn back at about 11 a.m. In comparison, its maiden flight was 80-minutes long. (Reporting by Brenda Goh; Editing by Stephen Coates)