The US Air Force has excluded the Textron AirLand Scorpion light-attack aircraft from the next phase of its OA-X experiment, leaving Textron Aviation's Beechcraft AT-6 Wolverine and the Sierra Nevada/Embraer A-29 Super Tucano as the finalists for a potential follow-on acquisition deal.

The news comes as a blow for joint venture Textron AirLand’s five-year-old campaign to win the endorsement of the US Air Force for the company-funded Scorpion, a twinjet designed to perform as a light-attack and observation platform.

Instead, the turboprop-powered AT-6 and A-29 are “the two most promising light-attack aircraft”, says Secretary of the Air Force Heather Wilson.

“This will let us gather the data needed for a rapid procurement,” Wilson says.

Textron Aviation declines to comment on the air force’s rejection of the Scorpion.

The AT-6 and A-29 will participate in the second phase of the OA-X experiment from May to July at Davis-Monthan AFB, Arizona, the USAF says. The second phase was originally planned as a demonstration in a combat zone, the third in a series of Combat Dragon events dating back to the Vietnam War.

“Rather than do a combat demonstration, we have decided to work closely with industry to experiment with maintenance, data networking and sensors,” Wilson says.

That characterization suggests an evaluation of the weapons capability of both aircraft is being de-emphasised in favour of surveillance and communications functions.

“This effort to find a lower-cost and exportable aircraft for permissive environments is directly in line with the National Defense Strategy,” says Gen David Goldfein, chief of staff of the USAF. “A light-attack aircraft would not only provide relief to our fourth- and fifth-generation aircraft, but also bolster our interoperability, so we can more effectively employ airpower as an international team.”

But the air force’s real support for the light-attack mission is difficult to judge until 12 February, when the Trump Administration is set to submit the Fiscal 2019 budget request to Congress. So far, the USAF has budgeted no funding to acquire an OA-X fleet, but that could change in the first budget request prepared from scratch by the government elected in 2016.

In 2015, Congress gave the Department of Defense authority to bypass normal acquisition procedures to make rapid purchases in certain circumstances, but only after performing a thorough evaluation of production-ready options. Such authority could allow the air force to move forward with an OA-X contract award as early as Fiscal 2019, but only if the programme is funded in next year’s yet-unreleased budget.