WASHINGTON — Textron Airland has officially decided against offering its Scorpion jet for the Air Force's T-X trainer competition, ending speculation about whether the aircraft would emerge as a dark horse candidate.

"We certainly believe the Scorpion can fit a good training role, not only for the U.S. Air Force but around the world, but with the requirements that had been put out there for the T-X, we don't believe the Scorpion fits all the requirements," said Bill Harris, the company's vice president of Scorpion jet sales.

Textron told Defense News in early 2016 that it would probably not pursue the T-X contract unless the Air Force changed its requirements to be less demanding. However, earlier this winter, company officials stated that they had not ruled out a T-X bid and were assessing the final request for proposals.

Harris explained Textron wanted to take a second look at the requirements to evaluate whether Scorpion could fit the service's needs, but the jet had trouble meeting some of the Air Force's more aggressive performance characteristics, including a high G threshold of 6.5 — the Scorpion can achieve 6 Gs.

"It basically was very close to what you would see in an F-16 Block 50 aircraft," he said. "We went over it and over it, and it became clear that we weren't going to meet these aggressive performance standards."

That leaves five teams still in the ring to fight over the $16 billion contract: Boeing and Saab’s clean-sheet design, Lockheed Martin and Korea Aerospace Industries modified T-50, Leonardo DRS’s T-100, Sierra Nevada Corp and Turkish Aerospace Industries’ newly designed Freedom Trainer, and newcomer Stavatti Aerospace’s Javelin concept.

Proposals are due March 30, and the Air Force plans to award a contract this year. The program of record currently includes 350 planes and ground training systems, however industry has speculated there could be an opportunity to sell hundreds more T-X aircraft domestically and internationally.

The decision not to bid on the T-X opens Textron up to focus on an upcoming light attack demonstration with the Air Force, as well as its ongoing cooperative research and development agreement (CRADA) with the service to conduct an airworthiness assessment of the Scorpion, Harris said.

Textron and the Air Force recently completed the first phase of the CRADA, in which the parties laid out the evaluation procedures and what elements of the aircraft would be assessed. Within weeks, the company will begin the second phase, which involves providing engineering analysis and data from ground and flight tests, he said.

"We’re flying the first production aircraft, P1, and expanding that envelope, and as we do that, that is the aircraft that has all of the sensors on the aircraft to take in the data," he said. "Then, in the near term … we will start building some of these ground test articles, which are just subcomponents of the airplane that we’ll begin tests on."

The entire process will take about two years to complete, Harris said.

The Scorpion is the first aircraft that will undergo an Air Force airworthiness assessment without being acquired by the service or a foreign military, although Harris hopes the CRADA will improve the jet’s chances of landing its first customer. The company expects several countries will put out requests for proposals this year that could be a good fit for Scorpion, but Harris acknowledged that Textron is "not as near as we’d like" to finding a launch customer.

Textron rolled out the Scorpion in 2013 and conducted its first flight with a proof-of-concept demonstrator aircraft that year. The company has since embarked on a limited run of three production-conforming aircraft, which it is using to expand the aircraft's flight envelope and validate its mission systems.

P-1 made its first flight on Dec. 22 and is approaching 70 flight hours, Harris said. The second production aircraft, P-2, is headed for its first flight in a matter of weeks, and P-3 is currently under construction.

Valerie Insinna is Defense News' air warfare reporter. She previously worked the Navy/congressional beats for Defense Daily, which followed almost three years as a staff writer for National Defense Magazine. Prior to that, she worked as an editorial assistant for the Tokyo Shimbun’s Washington bureau.