The Air Force is drafting requirements for a plane to replace the A-10 Warthog, which Congress has refused to let the service retire, according to reports.

Lt. Gen. Mike Holmes, the deputy chief of staff for strategic plans and requirements, said Thursday that Air Force Chief of Staff Gen. Mark Welsh will be given the document to review soon.

"That [close-air support] replacement airplane, I have seen a draft of it, it's out for coordination. It'll go to the chief sometime this spring and let the chief shape it, he's our chief requirements officer also in the Air Force, and then we'll fold that into the larger study we're doing on the future of the combat air forces," Holmes said, according to Defense News.

The Air Force has tried for several budget cycles to retire the A-10, saying that it needs the money to bring the new F-35, along with all the maintenance staff it requires, online. But lawmakers have repeatedly refused, because they hear from troops that the A-10 is still the best aircraft to provide close-air support in the fight against the Islamic State.

Once the document is approved, officials will decide the best, most cost-effective option to meet the requirement. That could mean building a new aircraft, using an existing plane or extending the life of the Warthog, Holmes said.

The Air Force is set to retire the final A-10 in 2022.