Wichita ? The Air Force has notified Hawker Beechcraft Corp. that its Beechcraft AT-6 has been excluded from competition to build a light attack aircraft, a contract worth nearly $1 billion, the company said.

The company had hoped its AT-6, an armed version of its T-6 trainer, would be chosen for the Light Air Support Counter Insurgency aircraft for the Afghanistan National Army Corps. The chosen aircraft also would be used as a light attack armed reconnaissance aircraft for the U.S. Air Force.

The piston planes are designed for counterinsurgency, close air support, armed overwatch and homeland security, The Wichita Eagle reported.

Hawker Beechcraft officials said in a news release they were “confounded and troubled” by the Air Force’s decision. The company said it is asking the Air Force for an explanation and will explore all options.

Hawker Beechcraft said it had been working with the Air Force for two years and had invested more than $100 million to meet the Air Force’s requirements for the plane. It noted that the Beechcraft AT-6 had been found capable of meeting the requirements in a demonstration program led by the Air National Guard.

“We have followed the Air Force’s guidance close, and based on what we have seen, we continue to believe that we submitted the most capable, affordable and sustainable light attack aircraft,” the company said.

The company has said winning the contract would have kept its T-6 production line running after 2015. About 1,400 employees in 20 states, including 800 in Wichita, work on the AT-6 and T-6 programs for Beechcraft and its U.S. suppliers and partners.

U.S. Rep. Mike Pompeo, a Republican who represents Wichita, said in a news release that he was disappointed to learn Hawker-Beechcraft’s proposal was excluded from the competition.

“I have already demanded answers from the Pentagon on why they made this very unfortunate decision, and will continue to do so,” Pompeo said. “This contract is critical both to our nation’s security and to jobs in Wichita, Kansas.”