Air Force Secretary Frank Kendall Makes The Right Call On F-35 Fighter Propulsion

Secretary of the Air Force Frank Kendall disclosed this week that his service will not support development of a new engine to power its F-35A fighters. Instead, it will invest in upgrades to the existing F135 engine, so that the engine can support future performance gains by the fighter.

I can’t say that I’m surprised. Well over a year ago, I penned a piece for Forbes entitled “Move To Replace F-35 Fighter Engine Probably Isn’t Affordable,” and affordability was the main factor Kendall cited Monday in deciding not to seek a new engine.

It’s not that Kendall didn’t like the idea of a new engine. General ElectricGE
Aerospace and Raytheon TechnologiesRTX
unit Pratt & Whitney have been developing potential successors to the F135 engine since 2016. Both companies have offered designs that would bolster thrust and fuel efficiency while still fitting into the Air Force variant of the fighter.

The problem was that installing a new engine on the Navy and Marine versions of the fighter would be more challenging—in fact, nearly impossible on the Marine version—and the sea services therefore weren’t interested in helping the Air Force fund a new engine.

Moreover, the dozen or so overseas partners who have committed to buying the F-35, mainly the Air Force variant, were barely aware there was discussion of pursuing a different engine. Their enthusiasm for an all-new engine was likely to be muted at best.

Thus, in addition to footing the entire bill for developing a new engine, the Air Force had to consider the potential fallout generated by fielding a global F-35 fleet sporting multiple engine types. The increase in logistics costs across several decades of operation would have totaled in the tens of billions of dollars.

Secretary Kendall, an aerospace engineer by training, therefore gave up on the idea of buying a new engine for F-35. The defense department will still move ahead with efforts to develop a next-generation powerplant for future tactical aircraft, but the next-gen solution won’t be installed on F-35 fighters.

This is very good news for Raytheon, a contributor to my think tank that now looks poised to continue sharing the domestic market for afterburning turbofans with rival GE through mid-century. The F135 engine will also power the Air Force’s new B-21 bomber.

General Electric had sought to use the prospect of a new engine program to gain market share, having previously been rebuffed in its efforts to win a berth on the F-35.

However, that would have required GE to win a competition against the potential F135 successor developed by Pratt & Whitney. Even if Kendall decided an all-new engine was needed, there was no guarantee GE would have won that competition.

Pratt & Whitney’s argument all along was that it could build a better engine if necessary, but the F135 had plenty of growth margin for powering future fighter upgrades. By improving the existing engine rather than developing a new one, it argued, the Air Force could meet its future performance goals faster and at much less expense.

Although Kendall did not allude to the long-term sustainment costs of supporting a fleet powered by diverse engines, that undoubtedly played a role in how he and service acquisition executive Andrew Hunter assessed the possibility of pursuing an all-new engine.

If half the Air Force fleet consists of fighters powered by the F135 and the other half consists of fighters powered by a different engine, that would require two supply chains, two stores of spare parts, two sets of maintainers, two sets of support manuals, and all sorts of other investments that now can be avoided.

GE argued that some of those costs would be offset by the fuel savings and performance gains a new engine would deliver, but Kendell knew from long experience that there would likely be difficulties involved in fielding a new engine that would not arise if the Air Force simply evolved its existing engine.

The last thing the Air Force needs is delays in its plan to upgrade the F-35 fleet with dozens of enhancements designed to address emerging threats—an effort collectively known as the Block 4 project.

By tacitly acknowledging that an improved F135 engine can support those enhancements to the airframe, Secretary Kendall has avoided a lot of expense and a fair amount of risk to the program.

His solution is the cheapest and the safest. All of which tends to confirm my judgment in the 2021 Forbes piece that Frank Kendall is “as close to being an honest broker on tech questions as our present political culture is likely to deliver.”

As noted above, Pratt & Whitney parent Raytheon Technologies contributes to my think tank.