WASHINGTON — Raytheon and Leonardo-Finmeccanica's disagreements about the T-X trainer program appear to be in the rearview mirror, as the companies revealed on Monday that their T-100 aircraft would be assembled in Mississippi.

If the US Air Force selects the T-100 for its T-X program, Raytheon will build a final assembly and checkout facility (FACO) in Meridian, Mississippi, to complete construction of the trainers, the company said in a statement. Raytheon announced earlier this year that it had partnered with Leonardo to offer a version of the firm's Aermacchi M-346, with CAE providing the ground-based training element and Honeywell manufacturing the aircraft's engines.

Although Raytheon had committed to conduct assembly of the aircraft in the United States, exactly how much of the trainer would be manufactured stateside remained an open question — and a subject of conflict between Leonardo and Raytheon — until just recently, multiple sources told Defense News last week.  

"At issue was never where the aircraft would be built. It was how much, what parts, those kinds of things," one source explained.

Another source said that Raytheon was ready to walk away from the partnership.

That issue and others were solved during an Oct. 14 meeting between Leonardo and Raytheon officials, they said.

At least 70 percent of the T-100 training system — including ground-based systems —will be built in the United States, a Raytheon spokesman said. Under the terms of the agreement, Raytheon would be responsible for final assembly, checkout and delivery at the Meridian site, while structural assembly will take place in Italy.

"Our process determined that the best location for building the T-100 is Meridian, Mississippi," Rick Yuse, president of Raytheon Space and Airborne Systems, said in a statement. "It provides the right blend of infrastructure, proximity to our customers, government support and a talent base that's ready for the high tech jobs critical to our success."

The Meridian-based FACO site would be entirely new construction for Raytheon, which manufactures active electronically scanned array in the nearby city of Forest, Mississippi. Should Raytheon be awarded the contract, it would bring "hundreds" of jobs to the state, Mississippi Gov. Phil Bryant said in a statement.

Several other firms are competing against the Raytheon-Leonardo team. Incumbent T-38 manufacturer Northrop Grumman and a Boeing-Saab partnership have designed clean-sheet trainers and built their first demonstration aircraft. Lockheed Martin has joined with Korean Aerospace Industries to offer the T-50A, a version of the latter's T-50. Their first two T-50A jets conducted their inaugural flights this summer.

The Air Force plans to buy 350 T-X training aircraft and intends to release its final request for proposals by the end of the year.