GE Aerospace and Pratt & Whitney — the two engine manufacturers competing to power the United States Air Force’s Boeing F-47 sixth-generation air dominance fighter — have each completed Assembly Readiness Reviews of their respective adaptive-cycle turbofan designs within days of each other in the second week of May 2026, representing the most substantive public disclosure of parallel programme progress since both companies received up-to-$3.5 billion contracts under the Next Generation Adaptive Propulsion (NGAP) programme in January 2025.
GE Aerospace confirmed on May 11, 2026, that it had completed an Assembly Readiness Review of its XA102 adaptive-cycle engine. Pratt & Whitney, on the other hand, had already announced completion of its own equivalent review — a fully digital Assembly Readiness Review of its XA103 engine — on May 8, 2026.
GE Aerospace XA102: Assembly Readiness Review Cleared on May 11
GE Aerospace completed the Detailed Design Review (DDR) of the XA102 in February 2025, at which point it presented a comprehensive digital engine model to the U.S. Air Force and validated its readiness for full-scale demonstrator build. Following the DDR, GE Aerospace was awarded the next contract phase to procure, assemble and test an XA102 full-scale demonstrator engine.
The Assembly Readiness Review completed on May 11 now clears the engine for the build phase, signifying that the assessment addressed not only the design maturity of the XA102 itself, but also the manufacturing process infrastructure and supply chain architecture that will support physical production of the demonstrator.
Aviation Week reported that the review’s scope encompassed this broader industrial readiness dimension. GE says it expects the U.S. Air Force to award funding for the next phase of NGAP development later this year. Commenting on the milestone, Dr. Steve “Doogie” Russell, Vice President and General Manager of GE Aerospace’s Edison Works advanced projects unit, stated:
“With the completion of the Assembly Readiness Review, we are demonstrating the maturity of our XA102 engine design and the strength of our digital-first approach to developing next-generation propulsion systems.”
A defining feature of the XA102’s development trajectory is that it is the first engine in GE Aerospace’s history to be designed entirely using model-based systems engineering (MBSE), which is a digital-first methodology where a comprehensive virtual model of the engine serves as the authoritative source of design truth for all engineering disciplines, supply chain partners, and test planning activities.
GE Aerospace’s official press release emphasised that this approach delivers “improved range, survivability and thermal management capabilities for advanced weapons and sensors.” The XA102 builds upon the prior-generation XA100, which completed multiple successful rounds of testing under the AETP and whose accumulated data provided a validated technological foundation for the sixth-generation design.
Pratt & Whitney XA103: A Fully Digital Review and the Transition to Physical Hardware
Three days before GE’s May 11 announcement, Pratt & Whitney published its own milestone on May 8, 2026, through an RTX press release: the completion of a fully digital Assembly Readiness Review for its XA103 engine — the first fully digital technical assessment of its kind for a programme of this classification and scale.
The milestone marks Pratt & Whitney’s transition from designing the XA103 in a digital environment to procuring and producing physical hardware from its supply network. Unlike a conventional review process, the XA103’s Assembly Readiness Review was conducted entirely through digital models — an approach the company describes as not merely a process efficiency, but as the validation of a new paradigm for military propulsion development.
Pratt & Whitney’s official RTX press release quoted Jill Albertelli, President of Pratt & Whitney’s Military Engines business, as stating:
“This milestone demonstrates Pratt & Whitney’s investment in digital infrastructure, showcasing seamlessly integrated digital capabilities and reinforcing our strong collaboration with the U.S. Air Force. As we move forward with assembling our engine for testing, our NGAP team is simultaneously developing novel digital validation tools. The performance we expect this engine to deliver exceeds anything available today, reinforcing the critical importance of continuous improvement and stable investment in maintaining propulsion as a strategic competitive advantage.”
Albertelli had previously, at the DDR stage in February 2025, described the significance of the digital methodology itself, saying: “The significance of this first fully digital review cannot be understated. Digital processes throughout the lifecycle are crucial to rapidly and efficiently deliver advanced warfighter capabilities.”
The XA103 draws on Pratt & Whitney’s accumulated experience from nearly two million flight hours on the F119 and F135 — a data foundation that the company says directly informs the sixth-generation design’s adaptive architecture and reliability targets.
Aerospace Global News reported that the XA103’s model-based digital design environment has already halved the pace at which it delivers technical data packages, by distributing advanced digital models to suppliers and engineers — enabling rapid design iteration, easier system integration, better forecasting for manufacturing resources, and faster model testing.
The engine is described by Pratt & Whitney as “platform-agnostic” meaning its adaptive architecture is designed for applicability across multiple future combat aircraft types, not solely the F-47. Testing of the assembled XA103 is expected in the late 2020s.
What Is NGAP, and Why Does It Matter For the F-47?
On March 21, 2025, President Donald Trump announced that Boeing had won a contract worth more than $20 billion to design and build the F-47, the first crewed sixth-generation fighter aircraft the United States has ever committed to full engineering and manufacturing development.
The F-47 is intended to succeed the Lockheed Martin F-22 Raptor and operate alongside a fleet of more than 1,000 uncrewed Collaborative Combat Aircraft (CCA) — with first flight expected in 2028 and operational fielding targeted for the 2030s. The propulsion system it will carry has not yet been formally selected: that determination will follow the full-scale demonstrator test phase that both NGAP competitors are now entering.
The Next Generation Adaptive Propulsion programme is the U.S. Air Force’s formal initiative to develop a new class of propulsion systems sufficiently advanced to power sixth-generation crewed combat aircraft.
NGAP traces its origins to earlier adaptive engine efforts that began in 2007 under the Adaptive Versatile Engine Technology initiative, followed by the Adaptive Engine Technology Demonstrator in 2012, and the Adaptive Engine Transition Program (AETP) in 2016 — under which GE developed the XA100 and Pratt & Whitney developed the XA101 as competing demonstrators, initially with potential F-35 re-engining in mind.
As sixth-generation fighter requirements evolved and the NGAD programme took shape, the Air Force separated NGAP as a distinct propulsion track optimised for the NGAD crewed aircraft and its extreme operational demands.
The competing designs under NGAP are the GE Aerospace XA102 and the Pratt & Whitney XA103. Development contracts for these engines carry ceilings of up to $3.5 billion per company through 2032 — a figure that is itself more than three times the $975 million ceiling on the original contracts awarded in 2022, reflecting the substantial expansion of scope and ambition since programme inception.
Defense News reported that the Pentagon characterised the contract awards as intended to help deliver “a state-of-the-art propulsion system with a flexible architecture that can be tailored for future combat aircraft operating across various mission threads, and digitally transforming the propulsion industrial base.” The programme timeline anticipates full-scale ground demonstrator testing through the late 2020s, with the Air Force expected to award funding for the next development phase to both competitors later in 2026, according to GE Aerospace’s own statement accompanying the May 11 milestone.
The NGAP engine is designed to achieve performance levels that the current generation of military turbofans — specifically Pratt & Whitney’s F119, which powers the F-22, and the F135, which powers the F-35 — cannot approach. GE Aerospace’s XA102 is designed to provide up to 30% greater range compared to the most advanced combat engines currently available, alongside significantly superior thermal management capabilities.
Pratt & Whitney’s XA103, likewise, is engineered to deliver adaptive performance that balances thrust, fuel efficiency, thermal management, and onboard power generation in real time — a dynamic capability that fixed-cycle engines are architecturally incapable of replicating.
The Air Power Asia analysis published in January 2026 confirmed that both engines target a thrust class of approximately 35,000–40,000 pounds-force, with specific goals including a 25% reduction in average fuel consumption relative to current combat engines and a substantive reduction in cooling air temperature.
What Adaptive-Cycle Technology Means: Beyond the Fixed-Cycle Engine Paradigm
The adaptive-cycle architecture that both the XA102 and XA103 embody represents the most fundamental departure from fighter engine design since the introduction of the afterburner. Current combat engines — including the F119 in the F-22 and the F135 in the F-35 — are fixed-cycle turbofans. That is, their thermodynamic cycle is optimised for a single performance point, whether maximum thrust or fuel efficiency, and the engine operates at or around that fixed design condition throughout a mission.
An adaptive-cycle engine introduces a third stream of airflow that the engine management system can dynamically redirect between maximum-thrust and fuel-efficient cruise modes in real time.
The operational consequences for a platform like the F-47 are profound. Air Power Asia’s January 2026 analysis confirmed the programme’s specific performance goals:
- a 25% reduction in average fuel consumption
- a substantive reduction in cooling air temperature
- a step-change in the quantity of electrical power the engine can generate to feed next-generation sensors, electronic warfare systems
- directed-energy weapons whose power demands exceed what current combat engines can supply.
For the Indo-Pacific theatre, where the F-22’s combat radius of approximately 590 nautical miles has been identified by successive Air Force assessments as operationally inadequate against Chinese integrated air defence systems.
The WarZone’s reporting on the F-47 contract noted that the platform is envisioned with a combat radius beyond 1,000 nautical miles and the ability to operate as the manned command node for up to eight Collaborative Combat Aircraft drone wingmen simultaneously. Neither of those requirements is achievable without a propulsion system that can dynamically shift between high-thrust and high-efficiency modes across extended mission profiles. The adaptive cycle addresses this envelope.
The Congressional Budget Office has estimated that each F-47 could cost up to $300 million, approximately three times the cost of an F-35. The propulsion system is a primary driver of that figure, and both GE Aerospace and Pratt & Whitney are leveraging digital engineering methodologies as their principal tool for keeping costs tractable — even as the technical demands they are asked to meet exceed those of any combat engine previously built.
The F-47 Programme: Context for the Propulsion Competition
The NGAP programme does not exist in isolation. It is the propulsion pillar of the NGAD initiative, whose broader architecture encompasses the F-47 crewed fighter, the Collaborative Combat Aircraft drone fleet, and the command, sensor, and communications infrastructure that ties them together. On March 21, 2025, Trump announced Boeing had been selected as the prime contractor for the F-47 over Lockheed Martin, in what the aviation industry widely characterised as a major strategic upset. Aerotime reported that the initial contract is valued at approximately $20 billion covering Engineering and Manufacturing Development, with first flight anticipated in 2028 and operational fielding in the 2030s. Boeing’s defence business — which had accumulated more than $7 billion in cost overruns on the KC-46 tanker programme and faced concerns about the wind-down of its F/A-18 Super Hornet production line by 2027 — regarded the F-47 award as a strategic lifeline for its fighter manufacturing infrastructure in St. Louis, Missouri.
The Air Force’s fiscal 2025 budget request allocated $3.3 billion for NGAD development: $2.7 billion for the manned F-47 and $557 million for Collaborative Combat Aircraft. The Air Force has also requested $2.58 billion for NGAP and the broader NGAD programme in its fiscal 2026 budget. The NGAD programme had faced its most acute existential threat in May 2024, when then-Secretary of the Air Force Frank Kendall placed it on formal pause amid cost concerns — with per-unit estimates approaching $300 million per aircraft, or triple the price of an F-35. The pause ended when Trump’s administration resumed the programme following the 2024 election, and the F-47 contract award in March 2025 signalled that the need for a sixth-generation crewed fighter in a potential Indo-Pacific conflict had ultimately outweighed the affordability objection. Wikipedia’s F-47 article confirms a planned procurement of approximately 185–200 aircraft to pair with more than 1,000 CCA drones — roughly two uncrewed systems per F-47 and per F-35A in the combined fleet.