AP — Beechcraft is contesting the U.S. Air Force’s decision to award a contract for a light air support plane to Sierra Nevada Corp.

The Wichita-based aircraft maker announced Thursday that it had filed a lawsuit in the U.S. Court of Federal Claims in Washington.

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.

Beechcraft says its plane is cheaper and better.

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