The Chinese fighter test aircraft, unofficially called J-20, has completed its first flight.

Photos of the J-20 flying show it remaining in a tight pattern with its undercarriage extended.

A two-seat J-10 fighter acted as chase plane for the J-20 during the flight, which has been awaited since the big fighter began taxi tests at Chengdu in December (Aerospace DAILY, Jan. 4).

An observer posting reports of proceedings to the Global Times, apparently from the fence at Avic’s Chengdu facility, said the aircraft began moving at 12:50:08 local time (04:50:08 GMT), noting a second later the aircraft was “accelerating” and at 12:50:16 “flying.” The landing was reported 18 min. later.

The events mean the J-20 (or J-XX since the official designation has not been released) completed its first flight at about 1 p.m. on a date written in Chinese notation as 11.1.11. There may be symbolism to the timing since a Chinese saying “yi fei chong tian” begins with the character for “one” and means something like “charge straight into the sky.”

The flight also occurred during a visit to China by U.S. Defense Secretary Robert Gates, who says Chinese President Hu Jintao confirmed the first flight to him in talks.

Two passenger aircraft, one a Boeing 737, arrived at the Chengdu facility less than an hour before the J-20’s takeoff, presumably carrying important officials.

It is unclear whether the J-20 is a prototype or only a technology demonstrator.

The stealthy aircraft is not the only advanced combat aircraft program underway in China though. The deputy chief of the air force, He Weirong, said in November 2009 that in 2017-19 China would field a “fourth-generation” fighter, which in China means an aircraft of F-22-like technology. He was not referring to the J-20, however, because a month later a prominent news report in English quoted the air force as saying that the 2017-19 fighter would be an improved J-10.

It is quite possible that the improved J-10 could refer to supercruise capability, since the Chinese navy has said that it needs a supercrusing aircraft.

The Chengdu plant that built the J-20 is part of the Avic combat aircraft division, Avic Defense.