US Congress wants advanced engines in all F-35 variants

US lawmakers want strategies from the Pentagon for integrating advanced propulsion systems into all three variants of the Lockheed Martin F-35 Lightning II Joint Strike Fighter.

The fiscal year (FY) 2022 National Defense Authorization Act (NDAA), signed into law on 27 December 2021, directs the US Air Force (USAF) secretary to provide a report on integrating the Adaptive Engine Transition Program (AETP) engine into the F-35A conventional variant no later than 14 days following submission of the service's FY 2023 budget proposal. This report must have a competitive acquisition strategy and a plan to begin activities for retrofitting all F-35As starting no later than FY 2027.

The NDAA also wants a strategy from the US Navy (USN) secretary and undersecretary of defence for acquisition and sustainment for integrating an advanced propulsion system into the F-35B short take-off and vertical landing (STOVL) model and the F-35C carrier variant. The legislation defines an advanced propulsion system as a derivative of an engine developed under AETP or a derivative of a propulsion system previously developed for the F-35.

This strategy for the B- and C-models must have an analysis of the effects of an advanced propulsion system on the combat effectiveness and sustainment costs of F-35B and F-35C aircraft. This analysis must include any effects resulting from increased thrust, fuel efficiency, thermal capacity, and electrical generation and improvements in acceleration, speed, range, and overall mission effectiveness.

The assessment must also include how integration of an advanced propulsion system into the B- and C-models may result in a reduction in dependency on support assets, such as air refuelling tankers, and an overall cost benefit to the Pentagon from reduced acquisition and sustainment for such support assets.