The two proposed engines that might one day power a sixth-generation U.S. Air Force fighter have passed an important design review, defense firms announced this week.
And with the detailed design reviews for GE Aerospace’s XA102 and Pratt & Whitney’s XA103 now complete, the companies are moving forward to build prototype demonstration engines to prove they will work.
The XA102 and XA103 are GE’s and Pratt’s pitch for the Air Force’s Next Generation Adaptive Propulsion program, which is intended to be the propulsion system for the crewed fighter portion of the Next Generation Air Dominance, or NGAD, family of systems.
Both engines use adaptive technologies that would allow an NGAD aircraft to adjust to the ideal thrust configuration for its situation, providing greater range and thermal management capability than traditional engines. That technology was considered for the F-35 Joint Strike Fighter, but the Pentagon ultimately chose to upgrade the F-35′s current engines amid concerns about the adaptive engine’s costs and limited ability to fit all versions of the F-35.
In separate releases this week, each company touted the new digital techniques it used for designing and systems engineering of its engine.
Pratt & Whitney, a subsidiary of RTX, said the “collaborative digital environment” the company used to design its engine allowed the company to electronically send reviewers the data they needed to verify the XA103′s plans.
“The significance of this first fully digital review cannot be understated,” Jill Albertelli, president of military engines for Pratt & Whitney, said in a Thursday release. “Digital processes throughout the lifecycle are crucial to rapidly and efficiently deliver advanced warfighter capabilities.”
GE called the XA102′s use of model-based systems engineering “a transformative shift in how advanced propulsion systems are designed and tested.”
“GE Aerospace is making great strides with model-based engineering, which has been instrumental in the success of the XA102 engine design,” Steve Russell, vice president and general manager of GE Aerospace’s Edison Works, said in a Wednesday release. “As we transition into the procurement and build phase, we will continue to incorporate this innovative approach while working closely with our supply chain partners to advance the engine toward a full-scale demonstration.”
The Air Force in January announced both companies had been awarded modifications to their initial NGAP contracts that bring each contract’s maximum prototype phase value to $3.5 billion apiece. That ceiling would be more than three times the maximum $975 million value of the original contracts, which were awarded in 2022.
The companies are now procuring the hardware needed to build the prototypes. Pratt & Whitney said it expects to test its prototype by the end of the decade.
However, it remains to be seen whether the futuristic NGAD fighter will even be built one day and in what form. The Air Force last summer put its NGAD program on hold amid higher-than-expected potential costs and started looking at ways to achieve air dominance at a lower price. After the 2024 U.S. presidential election, then-Air Force Secretary Frank Kendall decided to let the Trump administration make the final decision on NGAD, though the service’s studies found NGAD was needed.
Meanwhile, the Navy also announced Wednesday that it had awarded Pratt & Whitney a $186 million cost-plus-incentive-fee contract to fund sustainment of the F-35′s F135 engines. The contract includes funds for material and support equipment for depot maintenance facilities, program administration for nonrecurring sustainment activities, supplies, services and planning to activate depots and unit-level support equipment to help sustain F135s.
Pratt & Whitney was also awarded a three-year, $1.5 billion contract in December to sustain the F119 engines that power Air Force F-22 Raptors, which the company said will improve readiness and reduce costs for more than 400 engines.
Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.
