Artist’s concept of the XA100 engine, GE Aviation’s entrant in the Adaptive Versatile Engine Technology program.

Artist’s concept of the XA100 engine, GE Aviation’s entrant in the Adaptive Versatile Engine Technology program. GE Aviation

Fund the New F-35 Engine—If Only to Keep Industrial Base Humming, Lawmaker Says

Rep. Wittman and allies want to reverse the Air Force decision to kill the alternate engine program.

The Air Force needs to keep building its new F-35 engine, if only to keep the U.S. industrial base working on next-gen engine technology for future fighter aircraft, argue Rep. Rob Wittman and other House authorizers who are trying to reverse the service’s decision to drop its Adaptive Engine Transition Program.

Members of Congress also want to protect 32 Block 20 F-22s the Air Force hopes to axe, according to HASC Chairman Rep. Mike Rogers’ markup of the annual defense policy bill, and prevent “unnecessary” wear and tear to an already-diminishing fleet of jets, Wittman, R-Va., told Defense One

The Air Force announced in its 2024 budget rollout that it would upgrade the F-35’s existing Pratt & Whitney engine through a program called engine core upgrade, or ECU, and not pursue a new engine through its Adaptive Engine Transition Program. But Rogers’ mark, released on Monday, would keep the adaptive program alive, despite Air Force officials saying it is too expensive to ever make it into the F-35.

Funding the program is not about whether it will actually fly in the F-35: “it’s about the technology at this point,” said Wittman, who chairs the House Armed Services’s tactical air and land forces subcommittee. 

But engine development is not cheap. House authorizers want over $1 billion in 2024 to fund both efforts: $588 million for AETP, funded by the Air Force; and $480 million for ECU, split between the Air Force, Navy, and Marine Corps. 

Pratt and General Electric both have teams developing an adaptive engine. 

Wittman and others view the money as an investment to keep the Pentagon's next-gen fighters on track. The technology Pratt and GE develop will lay the groundwork for the Next Generation Adaptive Propulsion, or NGAP, program, which is expected to power the service’s next fighter jets, part of the Next-Generation Air Dominance effort. 

“We're going forward with ECU and we're going forward with AETP and then both companies are going to compete because the technology there for a whole variety of reasons is going to be needed in the future. I think that that technology informs what happens with NGAP,” Wittman said.  

Congress can’t yet decide between ECU and AETP because it doesn’t have the “full awareness about what both engines can do,” as both are still in development, Wittman said. But the Pentagon will “need ECU, period,” because an adaptive engine won’t work on the Marine Corps version of the F-35, he said.

While House authorizers want more money for engine development, they also want to cut NGAD funding. Rogers’ mark trims more than $550 million from the Air Force’s $2.3 billion request, giving the reason as “program deferment.”

With the advent of “collaborative combat aircraft,” or CCAs—drones to accompany fighter jets into conflict, and the service’s E-7s and existing fighter fleet, lawmakers felt there were better uses for the funds to meet near term needs, one congressional aide said. 

Wittman’s subcommittee markup of the defense policy bill, released on Monday, would add more congressional oversight over NGAD—requiring both the Air Force and Navy to submit annual reports to Congress on “development and technology maturation progress.” It also asks the services to establish “threshold and objective key performance parameters regarding flyaway unit cost, gross/weapon system unit cost, aircraft cost-per-tail-per-year, and aircraft cost-per-flight-hour” to keep the program on track and prevent potential cost increases.

Wittman’s mark also would greenlight the Air Force’s plan to get rid of some of its old aircraft, such as A-10 Warthogs and F-15C and -D fighters, and put the savings toward future fighter aircraft.

However, Rogers’ markup would block the service’s proposal to shed 32 Block 20 F-22s. That would mark the second straight year that Congress has denied the request.

Service officials have said these F-22s will “never be a part of the combat force” because it would require too much effort and cost too much to get them ready for battle.

Wittman said the 2023 defense bill had already addressed the Air Force’s wish to get rid of its F-22s, yet “they tried to take another bite of the apple this year.”

“Our position has not changed—this retirement would add unnecessary wear and tear to our most combat-capable fleet and to a very small fleet of remaining F-22s,” the lawmaker said. 

Wittman also said the Air Force, which just this year reached its goal of purchasing 72 annually, would probably not be able to hold that number in the years to come. 

“I don't know that each year that we can maintain that. We always push the Air Force to make sure they get as close to 72 as they can,” he said. 

However, the Air Force’s plan for CCAs is promising, and combined with the E-7, could provide a “gap filler” to get the most out of the service’s existing fighters, Wittman said. 

The service is coming down about 350 fighters over the next five years, Air Force Secretary Frank Kendall told reporters in May. But even with a smaller force, Kendall has said the Air Force will still be able to do all the missions it needs to do.

And “counting the numbers” of fighters is secondary to the service right now, Kendall said. Moving forward as quickly as possible to build next-gen platforms takes precedence, he said. 

But before Wittman’s subcommittee can get its wishes, the bill still needs to go through the full HASC markup next week, through Senate authorizers, and appropriators. However, Wittman said he’s confident that the draft bill will make it through with minimal changes. 

“What we're trying to do is to prep the playing field as this gets in there to make sure we maintain everything and to make sure we're in the same thought process as the Senate. Because what we'd like is that these things don't change a lot —so that's what we've done, so I think that's where we'll end up,” he said.