Air Force officials told a Senate panel on Tuesday the plan to procure over 80 F-15EXs over the next five years is required to keep up with an operational pace that continues to challenge readiness levels, with the aircraft to serve as a gapfiller for the aging F-15C fleet while bringing F-35s onboard.

Lawmakers on the Senate Armed Services Airland Subcommittee pressed the witnesses on the current status to bring down F-35 sustainment costs and the capability for the F-15EXs to meet operational demands in the meantime.

Boeing’s F-15EX

“Based on the situation we find ourselves in, we need both 4th-gen and 5th-gen aircraft to be able to execute our missions. We were counting on 4th-generation aircraft, such as the F-15E, the F-16, the A-10, as well as the F-15C to fly through 2030’s. And our F-15C fleet is not going to make it,” Lt Gen. Arnold Bunch, the Air Force’s military deputy for acquisition, said during the hearing. “This is about filling a capacity need that our F-15C’s are not going to be available for.”

Bunch said the F-15EX, built by Boeing [BA], will fill a capability gap while Lockheed Martin [LMT] continues to manufacture its F-35 Joint Strike Fighter.

The Air Force’s recently released budget request detailed plans to buy eight F-15EXs for $1.1 billion in 2020, with the goal of eventually purchasing over 80 aircraft for $7.9 billion through FY ’24.

During a Senate Armed Services hearing last week, Air Force Secretary Heather Wilson and Chief of Staff Gen. David Goldfein offered their support for the F-15EX decision as a path to improve fighter capacity in the near-term and begin replacing the aging F-15C fleet (Defense Daily, April 5).

Sen. Angus King (I-Maine), the subcommittee ranking member, asked Bunch if this was a “sound decision” after lawmakers have previously expressed concern about the aircraft’s effectiveness on the battlefield and potential ramifications with the F-35 program.

The Air Force studied the benefits of doing a service life extension program from the F-15C, and ultimately decided against it, according to Bunch, who added the F-15EX would allow airmen to retain readiness at a higher level

Bunch said the transition time from an F-15C to F-15EX is three to six months compared to 18 to 36 months for an F-15C to F-35.

“We are not backing off in any way, shape or form the F-35 program. We are fully committed to the program. We need it to serve as the quarterback as we try to penetrate anti-access area denials areas. It is the only platform that can penetrate and do those missions,” Bunch said.

King pressed on the witnesses on what the F-15EX meant for the future of the F-35 noting that high sustainment costs for flying the next-generation aircraft appear to limit the program’s progress.  

“If we’re going to buy 1,700 of these aircraft, we’re not going to be able to do anything but maintain them if we don’t bring that cost down,” King said.

Bunch said the Air Force is focused on getting the F-35 down to $30,000 per flight hour, while adding that Pentagon officials are still pushing to reach $25,000 per hour by 2025.

“I don’t know that they can make that, but what we want them to do is try to drive down the cost down,” Bunch said.