BRIDGEPORT, Conn. >> An engineer who worked for a defense contractor has been charged with attempting to travel to China with stolen documents on the development of advanced titanium for U.S. military aircraft, federal prosecutors said Tuesday.

The defendant, Yu Long, 36, is a Chinese citizen and a permanent resident of the United States who lived in New Haven.

He was arrested Nov. 7 at an Ithaca, New York, home, two days after he allegedly attempted to fly to China from Newark, New Jersey, with proprietary material. The criminal complaint was unsealed Tuesday at a court hearing in Bridgeport.

Long’s attorney didn’t immediately respond to a message seeking comment.

Long worked at United Technologies Corporation from August 2008 until May as a senior engineer at a research center that served many of the conglomerate’s divisions.

“UTC is fully cooperating with the government’s investigation. Because it is an ongoing investigation, we have no comment at this time,” company spokesman John Moran said.

Investigators say that upon returning from a trip to China in August, Long was found by screeners at an airport in New York to be carrying a nearly completed application for work with a state aerospace research center in China. It described experiences at UTC including work on engines used by U.S. Air Force fighter aircraft.

The documents that he was carrying at the Newark airport came from a company other than UTC but were printed out during his time with the Connecticut-based company, according to court documents. The second company had been working with UTC as part of a consortium of major defense contractors convened by the Air Force to see whether costs for metals could be lowered.

Long is charged with transporting, transmitting and transferring in interstate or foreign commerce goods obtained by theft or fraud.