RTX advances F135 engine upgrade

• RTX completed a design review milestone for Pratt & Whitney’s F135 Engine Core Upgrade program.
• The review assessed engine design maturity, propulsion technology, and production readiness for the F-35 program.
• The upgrade is intended to provide additional power and thermal management for future F-35 variants.

RTX (NYSE:RTX) announced that its Pratt & Whitney business completed the F135 Engine Core Upgrade Risk Reduction Design Review, advancing the propulsion modernization program for the F-35 aircraft.

The review evaluated detailed design elements, propulsion technologies, integration efforts, and risk-reduction activities required to support F-35 Block 4 and future aircraft variants.

RTX said the review also assessed supply-base readiness for future production and retrofit activities, with the Engine Core Upgrade designed as a high-commonality upgrade for new and existing F135-powered aircraft.

RTX said the F135 Engine Core Upgrade is the selected propulsion modernization solution and is designed to be incorporated during aircraft production or through retrofit programs at F135 maintenance facilities.

RTX provides aerospace and defense technologies through businesses including Pratt & Whitney, which develops and manufactures aircraft engines and propulsion systems.

The company reported 2025 sales of more than $88 billion and supplies systems and services for commercial aviation, military aircraft, and defense programs.