Alenia North America and General Dynamics are teaming up to vie for a U.S. Air Force contract to build 350 T-38 fast jet trainer replacements.

The teaming agreement, announced today, is likely to round out the field of would-be competitors for the so-called T-X competition.

The competition is not likely to start until 2014 at the earliest, but the announcement comes as the Air Force plans to conduct a T-X industry day later in the month.

Alenia North America will provide the Alenia Aermacchi M346 — dubbed the T-100 for the U.S. sales campaign — while General Dynamics C4 Systems will handle prime contractor responsibilities, including subcontractor management and systems integration work, based on a letter of intent jointly signed by both companies.

The team vows to build the aircraft in the U.S.; they are currently built in Venegono, Italy. Executives have not said, however, if all of the aircraft for the U.S. would roll off of a stateside final assembly line or merely some portion of the buy if the team wins the competition.

Current M346 customers include Italy, Israel and Singapore.

The GD/Alenia team joins a familiar field. BAE will compete with the Hawk trainer and Northrop Grumman as its U.S. manufacturing lead. Lockheed Martin and Korea Aerospace Industries will propose the T-50. One exception in this arena, which has competed for other work abroad, is the arrival of Boeing in the competition.

The company plans to propose a clean-sheet design based on the forthcoming U.S. Air Force request for proposals. This is seen by some as a risky proposal because the Air Force has said it prefers to buy a trainer with as little development cost as possible. Boeing will either have to underwrite some of the development cost — as it has done with the KC-46A tanker program — or risk competing with off-the-shelf designs that may need less costly modifications.

In replacing the aging and maintenance-needy T-38 fleet, the Air Force plans to buy not only a fleet of aircraft, but an end-to-end training system, including sophisticated ground-based training aids.