WASHINGTON — After a decade fighting in the uncontested skies of the Middle East, the Air Force is now concerned about its readiness for the high-end fight just around the corner.

"If you ask about the readiness of the United States to fight violent extremism, we’re ready," said Air Force Vice Chief of Staff Gen. David Goldfein said Thursday March 10 during an event in Washington. "If you ask us to retake Estonia, if you ask us to fight in the Far East against a near-peer, we’re not as ready as we need to be."

From the close-air support (CAS) A-10 attack planes to the high-end F-16s, the Air Force's fleet has spent over a decade flying and training to protect soldiers on the ground in the Middle East, Goldfein said during the Credit Suisse/McAleese FY2017 Defense Programs Conference. But very little of the training to support missions in an uncontested environment is transferable to a near-peer conflict in contested skies, Goldfein warned.

For aircraft like the modernized F-16 Block 50, which is designed to suppress conduct suppression of enemy air defenses in a non-permissive environment, every flight hour dedicated to training for close-air support missions is one less training for the high-end fight, Goldfein said.

"So we are fully ready for the Middle Eastern violent extremist fight, 100 percent," Goldfein said. "But we are concerned about our readiness for the other fights that might be around the corner."

As the Air Force looks from the current conflict to a future battle against a near-peer adversary with surface-to-air missiles and anti-aircraft capability, like Russia or China, the service must upgrade its fleet, Goldfein stressed. This move toward modernization will one day include retiring the beloved A-10, he said.

"No weapon system can fly forever, and so we have to look at retiring the A-10," Goldfein said. "An Air Force that doesn't modernize fails, and if the Air Force fails the joint team fails."

The Air Force’s latest plan, reflected in the fiscal year 2017 budget request, is to retire the A-10 by fiscal 2022. The multirole F-35 has been billed as an across-the-board replacement for all of the Air Force’s legacy fighter jets. But in the out-years, the F-35 can only partially fill the capability gap left by the A-10, Goldfein said. 

"I would never look at you and tell you, 'Hey, the replacement, one-for-one, for the A-10 is the F-35,' " Goldfein said.

However, Goldfein stressed caveated that the Air Force is "passionately committed" to close-air support, even without the A-10.

Depending on the terrain and battlefield environment, the Air Force uses different aircraft across the fleet to protect soldiers on the ground from enemy fire, Goldfein emphasized. In Afghanistan alone, commanders have different CAS needs across four "quadrants," he said.

In the southern part of the country, where terrain is relatively flat, commanders want the A-10. But in the valleys and mountains of eastern Afghanistan, commanders want the high-endurance, unmanned MQ-9 Reapers. The long-range B-1 bomber is the best fit for CAS in the north, while commanders in the west want F-15Es.

"The point being that working with ground commanders we were actually able to optimize exactly what we put ahead to best meet the mission," Goldfein said. "We have evolved to the point where we actually use a variety of weapon systems … when we do this mission."

The Air Force is standing up a CAS integration group at Nellis Air Force Base, Nevada, to look at the future of the mission, Goldfein said. This effort could include a single-role A-10 replacement, or A-X, officials have said.

Twitter: @laraseligman