In response to the lawsuit filed by Hawker Beechcraft over the light air support (LAS) competition, competitor Sierra Nevada filed an action in the U.S. Court of Federal Claims yesterday seeking reinstatement of the contract that had been originally awarded to Sierra Nevada and its partner, Brazilian aircraft manufacturer Embraer.

After Hawker Beechcraft filed the lawsuit late last year, the Air Force set aside the original award and opened an investigation into the source selection process that had picked Embraer’s A-29 Super Tucano over the Hawker Beechcraft AT-6.

Sierra Nevada, a U.S. company based in Sparks, Nev., claims cancellation of the contract was “an extreme response to what appears to be paperwork errors on the part of the USAF.” Moreover, it added, “the revised request for proposal issued by the Air Force [last month] is tilted in favor of the competition.” The contract has an initial value of $355 million for 20 aircraft, with options on another 15. The potential for additional orders would make the contract worth approximately $1 billion over time.