Revving Up the F-35: Inside the Engine Core Upgrade Decision

The F-35 Joint Strike Fighter program, a cornerstone of U.S. and allied airpower, is undergoing a significant engine update. The Pentagon has decided to upgrade the existing Pratt & Whitney F135 engine, rather than developing a new adaptive engine. This decision marks a shift from the earlier Adaptive Engine Transition Program (AETP), which aimed to research and develop a new engine type that offered enhanced thrust, power, and cooling capabilities.

The AETP, initiated in 2016, involved General Electric (GE) and Pratt & Whitney designing new engines, with GE proposing its XA100 as a potential F-35 replacement. However, concerns about cost and compatibility across different F-35 variants led to the decision to upgrade the existing F135 engine. The F135 Engine Core Upgrade (ECU) by Pratt & Whitney emerged as the preferred option due to its cost efficiency and suitability for all F-35 variants.

This decision to upgrade rather than replace the engine is significant for several reasons. Firstly, it ensures compatibility across all F-35 variants without the need for extensive modifications. Secondly, it represents a major win for Pratt & Whitney, the maker of the F135 engine. The ECU is seen as a more cost-effective solution, ensuring that a larger number of F-35s can be procured and that funds are available for the development of future propulsion systems, such as those for the Air Force’s Next Generation Air Dominance Platform.

The upgraded engine is expected to provide the necessary power and cooling to support the F-35’s Block 4 modernization, which will introduce new capabilities and enhancements. This upgrade is crucial as the F-35 continues to evolve with advanced technologies and systems.

Pratt & Whitney has already begun preliminary design work on the Engine Core Upgrade, utilizing funds appropriated in recent years. The upgrade is intended to be a “drop-in” retrofit to existing F135 engines and is designed to be adoptable by international partners within existing frameworks. The retrofitting process can occur in existing depots, making it a logistically feasible option.

While GE expressed disappointment in the Pentagon’s decision, highlighting the advanced capabilities of their XA100 engine, the decision reflects the military’s focus on affordability and compatibility across the F-35 fleet. The ECU program is seen as a critical step in ensuring the F-35 remains a versatile and powerful asset in modern air warfare, providing enhanced performance while keeping costs in check.

In terms of economic impact, Pratt & Whitney’s contract for the F135 engine enhancement, valued at $115 million, supports thousands of jobs across the United States, with a significant workforce in Connecticut. This investment not only advances the capabilities of the F-35 but also contributes to the economy, highlighting the multifaceted significance of such defense programs​​​​.