NATIONAL HARBOR, Md. — The F-35 engine upgrade has cleared a major design checkpoint, positioning the effort to proceed to testing and eventual production, according to a senior executive at Pratt & Whitney.
Jill Albertelli, president of Pratt’s military engines business, said the successful risk reduction design review confirms integration progress with the airframe, validates the design, and signals readiness from an industrial base perspective. She spoke in an interview on Monday at the Air and Space Forces Association conference. Pratt’s parent RTX announced the same day that Albertelli will become president of Pratt & Whitney effective Jan. 1, 2027.
The Engine Core Upgrade, or ECU, for the F135 powerplant completed what Albertelli described as a risk reduction design review that is essentially equivalent to a critical design review, a Pentagon assessment that verifies a system’s design will meet performance and other requirements.
Albertelli said roughly one-third of the unique hardware for the first ECU test engine is now in process.
F-35 engine upgrade timeline and next steps
Albertelli said the next major step is the first engine test. She did not provide specific milestone dates and referred questions to the F-35 Joint Program Office. A senior Air Force official has previously indicated ground testing is expected to begin in 2027, with flight testing around 2030.
When the ECU concept was advanced several years ago, officials projected potential service entry as early as 2028. A Government Accountability Office review last year reported that ECU production is now expected to start in 2031.
Asked about fielding assumptions, Albertelli said Pratt aims to align with customer priorities and noted that funding constraints require balancing needs. She emphasized the company is meeting government milestones.
Performance, cost, and scope of the F-35 engine upgrade
Military officials say the engine program is intended to deliver more thrust and improved fuel efficiency. The ECU is also designed to restore expected engine life and support forthcoming Block 4 capabilities.
The Pentagon selected the ECU over pursuing an all-new adaptive propulsion system for the F-35. Albertelli said the chosen path will save tens of billions of dollars in maintenance costs compared to not upgrading the F135.
All three F-35 variants are slated to receive the F-35 engine upgrade, with retrofits planned for in-service aircraft. The Pentagon recently awarded a modification valued at about 240.8 million dollars for ECU work, following a 1.3 billion dollar base contract issued in September 2024.