Powering the future of the F-35

The F135 is the world’s most advanced fighter engine with proven readiness and reliability. The Engine Core Upgrade (ECU) builds upon that same architecture with a fleet-wide upgrade.
Four F-35s in flight

Proven. Capable. Retrofittable.

Pratt & Whitney’s F135 Engine Core Upgrade (ECU) delivers the durability and performance needed to enable Block 4 capabilities and beyond. Easily retrofittable in all F-35 variants, ECU is the only engine that offers all global F-35 operators the additional power and thermal management capacity needed to enable next-generation weapons systems and sensors. Utilizing cutting-edge technologies developed for advanced programs, ECU ensures the F-35 Lightning II remains the most advanced fighter for decades to come.

Why ECU?

Proven track record

F135 updated exhaust plug

The ECU builds on the architecture of the F135 – a proven engine with over 860,000 recorded flight hours and 20 years of reliable performance.

Variant common

Three F-35 variants

Commonality enables agility within the F-35 program. The ECU is the only engine upgrade that supports all three variants of the F-35 while leveraging existing production, supply chain and maintenance infrastructure to ensure global readiness.

Advancing technology

F135 engine

ECU leverages proven technology from the Navy’s Fuel Burn Reduction program and other cutting-edge advanced development programs to support the modernization needs of the F-35.

Retrofittable

F135 engine

As the only “drop in” propulsion modernization solution available to the F-35, ECU’s retrofittable design allows for upgrades to already fielded F-35s and new production F-35s, ensuring a common, capable fleet for all users.

Economically impactful

A technician on an assembly line

The F135 program contributed more than $2.2 billion to the U.S. economy in 2023. ECU for the F-35 protects existing U.S. infrastructure investments and creates new skilled labor and engineering jobs year-over-year to support program growth.

ECU for stakeholders

“I support the decision that we did make, which is to go with the ECU, which is an upgrade to the existing engine … when the department looked at this overall and looked at the alternatives, the right decision for the department was to go with ECU” (Testimony to House Armed Services Committee, Department of the Air Force FY24 Budget Request, April 27, 2023)

Frank Kendall

Secretary of the Air Force

“The Air Force is working with the JPO to implement the F-35 enterprise decision to move forward with the F135 Engine Core Upgrade and accompanying Power and Thermal Management System upgrade … the JPO-led BCA determined that the F135 Engine Core Upgrade will restore engine life and prevent degradation for all three F-35 variants and partner nations at the lowest cost.” (Written statement to SASC Airland Subcommittee Hearing, April 26, 2023)

Joint USAF statement by Hon. Andrew P. Hunter Assistant Secretary of the Air Force (Acquisition, Technology & Logistics) Lt. Gen. S. Clinton Hinote, USAF Deputy Chief of Staff (Strategy, Integration, and Requirements) Lt. Gen. Richard G. Moore Jr., USAF Deputy Chief of Staff (Plans and Programs) Lt. Gen. James C. Slife, USAF Deputy Chief of Staff (Operations)

“The F135 Engine Core Upgrade will restore engine life and prevent degradation for all three F-35 variants and partner nations at the lowest cost.” (Testimony to HASC TAL, FY 24 Budget Request of DoD for Fixed-Wing Tactical & Training Aircraft Programs, March 29, 2023)

Andrew Hunter

Assistant Secretary of the Air Force

“What this Engine Core Upgrade does is it gives us greater bring-back capability to the boat. What does that mean? We can bring back 1,000 lbs more to the boat, which gives us life. Fuel is life. Time on station is life for us. So that’s why we are excited about the ECU and PTMS upgrades.” (Testimony to HASC TAL, FY 24 Budget Request of DoD for Fixed-Wing Tactical & Training Aircraft Programs, March 29, 2023)

USMC Lt. General Michael Cederholm

United States Marine Corps

“Pratt and Whitney is one of the foremost leaders in advanced technology and defense manufacturing, and it is clear their F135 engine is superior and cost-effective.” (December 2023)

Rep. Rosa DeLauro

CT-3 and Ranking Member of the House Appropriations Committee

“I am both gratified and proud that the Pentagon is committing to sole source production of the F135 to Pratt & Whitney Aircraft over a costly alternative engine. This is the right decision for our warfighters, partner nations across the globe, and for American taxpayers.” (December 2023)

Rep. John Larson

CT-1

“When the Department of Defense submitted its budget request for Fiscal Year 2024, the decision was crystal clear – upgrading the existing F135 engine is the most efficient and cost-effective strategy to deliver increased capability for our servicemembers and international program partners in the F-35 enterprise.” (December 2023)

Rep. Joe Courtney

CT-2

“The PDR was a successful first step toward the capability the ECU will provide in meeting the challenging performance and durability requirements of the F135," said U.S. Navy Capt. Mitchell Grant, F-35 propulsion program manager. "The ECU will ensure that the U.S. and our international partners remain well positioned to outpace adversary threats.”

Capt. Mitch Grant

F-35 JPO propulsion program manager

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