Pratt & Whitney, a subsidiary of RTX, has been awarded a not-to-exceed contract worth $1.3 billion to continue the development of an upgrade for the F-35’s engine, as announced by the Pentagon on Monday evening.
This enhancement, known as the Engine Core Upgrade (ECU), aims to improve the performance, power, and cooling capabilities of the Pratt-made F135 engine. The current award is categorized as an undefinitized action, indicating that the Pentagon and Pratt are still finalizing the terms. The work conducted under this contract is expected to be completed by March 2028.
“This contract is critical to continuing our positive forward momentum on this program,” said Jill Albertelli, president of Pratt’s military engines business. “It allows us to continue work in the risk reduction phase with a fully staffed team focused on design maturation, aircraft integration, and mobilizing the supply base to prepare for production.”
The need for the ECU arises primarily from concerns regarding power and cooling systems within the F-35. The existing F135 engine is already facing challenges due to increased cooling demands, and upcoming Block 4 upgrades are expected to further elevate these temperature levels. The ECU is designed to restore engine life impacted by heating issues and to fully enable the capabilities introduced in Block 4. Additionally, a separate enhancement to the fighter’s cooling system will accommodate features beyond the Block 4 upgrades.
Last year, Pentagon officials made the controversial decision to proceed with a sole-source upgrade of the current engine with Pratt, rather than pursue a competitive replacement. This decision was based on the belief that a new engine would be excessively costly and not compatible with all three variants of the F-35. In contrast, the ECU upgrade is designed to be compatible with the existing F-35 A, B, and C models.
The ECU successfully cleared a preliminary design review in July, and Pratt has previously estimated the total cost for the ECU project could reach up to $2.4 billion, with an aim to begin deliveries in 2029. Pratt did not respond immediately to inquiries about the details of the contract awarded on Monday.
In a separate but related effort, Pratt & Whitney and GE Aerospace are competing to develop a new engine for the Air Force’s planned sixth-generation fighter under the Next Generation Adaptive Propulsion program. However, the program’s future remains uncertain as the Air Force seeks to significantly lower costs for the upcoming aircraft.
