Insight by Pratt & Whitney

3 reasons why re-engining the F-35 would be irresponsible

This content is sponsored by Pratt  & Whitney.

The Department of Defense (DoD) faces a crucial modernization decision on the F-35 Lightning II fighter, the most advanced – and most expensive – acquisition program in U.S. history. Depending on the path forward, billions more could be added to its tab.

Several years into the F-35’s Block 4 modernization effort, the DoD has a number of hardware and software improvements to the platform underway, which are...

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This content is sponsored by Pratt  & Whitney.

The Department of Defense (DoD) faces a crucial modernization decision on the F-35 Lightning II fighter, the most advanced – and most expensive – acquisition program in U.S. history. Depending on the path forward, billions more could be added to its tab.

Several years into the F-35’s Block 4 modernization effort, the DoD has a number of hardware and software improvements to the platform underway, which are necessary to keep the fighter ahead of evolving threats. One element that’s fallen by the wayside – until now – is engine modernization. Without it, the increased power and cooling demands of Block 4 will push the current F135 engine even farther beyond its original specification, negatively impacting engine durability and increasing sustainment costs.

There are two possible paths ahead: upgrade the existing engine with what Pratt & Whitney has dubbed the F135 Enhanced Engine Package (EEP), or pursue a brand new engine being developed under the U.S. Air Force’s Adaptive Engine Transition Program (AETP).

The facts and data are clear. One of those options will cost billions more, create a duplicative sustainment network and introduce unnecessary safety risks — causing major disruptions for the cornerstone platform of allied airpower at a time when its needed most. The other option does the opposite, building on a safe, proven architecture, strengthening the F-35 alliance, and saving taxpayers $40 billion over the lifecycle of the program.

Cost

In April, Air Force Secretary Frank Kendall told the House Armed Services Committee that the costs to just develop an AETP engine could exceed $6 billion. That figure doesn’t include production or sustainment costs, which would take years and sizable investments to reduce to levels approaching current engine costs.

“F135 EEP leverages DoD investments in adaptive technologies to deliver the capability needed for Block 4 and beyond at approximately one-third the development cost of a new engine,” said Jen Latka, vice president for the F135 program at Pratt & Whitney. “This upgrade is production cost neutral, retaining the affordability investments that have been made to date with the F135. In other words, all the money that the government has invested in driving cost out of the engine isn’t lost.”

And then there are sustainment costs. Given EEP is a block upgrade to the existing Pratt & Whitney F135 engine, it maintains the same production and sustainment infrastructure that’s used today. It’s also variant-common, applicable to the F-35A, B and C models, which has long been a foundational element of the program to drive economies of scale and reduce cost. All told, EEP can save the taxpayer $40 billion in lifecycle costs over the life of the program.

Re-engining the F-35 with an AETP engine would require standing up a separate, duplicative sustainment infrastructure and the associated logistics that go along with it. This will drive substantial costs and challenges into the program at a time when the existing sustainment requirements are not adequately funded. The bottom line: re-engining the F-35 is an exorbitantly expensive endeavor that will lead to a significant reduction in tails and starve other critical modernization priorities across the DoD of funding.

“With today’s challenging fiscal environment, the Services are facing tough decisions as they juggle all of their modernization priorities and make tradeoffs,” said Latka. “Re-engining the F-35 will be disruptive and costly and will come at the expense of 6th Generation capability.”

There’s a reason why upgrades to existing fighter engines are a regular occurrence for the DoD. The re-engining efforts of the past have rarely gone smoothly. Case in point is the new B-52 Commercial Engine Replacement Program (CERP), which has seen costs jump by more than 50 percent in its first year due to integration issues.

Risk

There’s no question that AETP is a critically important program that has pushed the boundaries of combat propulsion technology. However, it’s still only a handful of prototypes that have never left the test cell. Inserting a brand new, operationally unproven engine into a single engine fighter presents inherent safety risks. And that’s exactly why it has never been done in the DoD’s history — derivative block upgrades based on proven twin-engine experience are the norm.

“EEP builds on a safe, proven engine architecture with over 1 million flight hours of experience between the F119 and the F135,” Latka said. “Based on operational experience, the F135 is the safest fighter engine ever produced. EEP builds on that unmatched pedigree.”

In addition to safety, there’s also the risks associated with integrating a new centerline engine. An AETP engine will require significant air vehicle modifications to accommodate the use of the third-stream and additional weight – in fact, the real scope of these modifications are not even known. Despite what you may have heard, there’s only one true “drop-in” solution for the F-35 and that’s an upgrade to the existing engine.

The other element to consider is speed to fielding. With geo-political tensions around the world increasing, the U.S. Services and international allies need fully enabled Block 4 capability as soon as possible. As a derivative upgrade to the F135, EEP has the fastest schedule to field meaningful capability.

Designed from the onset to be integrated into production and/or retrofit during engine overhaul, EEP leverages existing production capability that is at full rate, a mature supply chain, and a growing maintenance network. This means greater quantities of upgraded F135s – and thus, more fully enabled Block 4 F-35 aircraft – than there will be with a new engine that needs to march up a steep learning curve. That’s an important consideration when it comes to staying ahead of near-peer adversaries.

Alliances

Integrated deterrence with our allies is a key pillar of the National Defense Strategy. Bifurcating the F-35 fleet with an AETP engine would weaken interoperability — a key selling point for the F-35 platform, both nationally and internationally – and strain relations with key allies. Throwing our international partners’ budgets into disarray while complicating infrastructure and hampering interoperability doesn’t exactly meet the objective of integrated deterrence.

In fact, if one member of the enterprise goes it alone with a new engine, that would translate to increased sustainment costs for everyone else. That won’t sit well with our allies who have committed considerable resources into a multi-national program that would suddenly cost more than they’ve budgeted for.

On the other hand, EEP maintains the international partnership and alliance approach of the program — preserving the ability to share cost and logistics over a broad enterprise to ensure F-35 interoperability and sustainability across multiple variants and users.