Aircraft manufacturer Beechcraft announced Thursday that it has filed a lawsuit to contest the U.S. Air Force's decision to award a contract for a light air support plane to Sierra Nevada Corp.

The suit, filed in the U.S. Court of Federal Claims in Washington, D.C., is the latest development in a bitter, high-stakes competition that has taken nearly three years with legal challenges from both sides.

The contract for 20 planes for use in Afghanistan is worth more than $427 million. It could be worth as much as $1 billion, depending on future orders.

Wichita-based Beechcraft insists its plane is cheaper and better than the one Sparks, Nev.-based Sierra Nevada, in a partnership with Brazil's Embraer, plans to build in Jacksonville, Fla.

Beechcraft also filed a protest earlier this month with the Government Accountability Office, claiming the decision puts an estimated 1,400 jobs in Kansas and other states in jeopardy. A GAO ruling on the protest is expected within 90 days, Beechcraft said in a statement.

Last week, the Air Force defended its decision, saying in a statement that it restarted the competition for the contract last May with a new evaluation team as well as internal and external advisers. Air Force spokesman Ed Gulick said in the statement that the Air Force is confident that its decision is well supported and that the proposals were fairly evaluated.