House Lawmakers Push Alternate F-35 Engine

Updated: 11:12 a.m., June 14.

House authorizers want over half a billion dollars to fund an alternative engine for the F-35—despite Air Force officials saying the program is too expensive to ever make it into the fighter. 

The Air Force recently decided it will upgrade the existing Pratt & Whitney engine through a program called engine core upgrade, or ECU, and not pursue a new engine through its Adaptive Engine Transition Program, citing cost and the fact that it wouldn’t work on all variants of the F-35.

However, House Armed Services Committee chairman Rep. Mike Rogers, R-Ala., wants to keep the adaptive engine program alive. The chairman’s markup of the annual defense policy bill authorizes $588 million to continue developing the new engine. The bill also would fully fund Pratt’s engine upgrade program, a senior congressional aide said. The Air Force asked for $245 million in 2024 for ECU. 

“We [did] the ECU funding and then we did the AETP line to keep that technology going as we head into the sixth-generation aircraft that the Air Force and Navy are hoping to field in the 2030s,” the aide told reporters on Monday. 

Air Force Secretary Frank Kendall has previously said building a brand-new, adaptive engine would cost more than $6 billion, which would force the Air Force to buy fewer F-35s.

The aide declined to say whether the adaptive engine would actually ever fly in the F-35.

If the funds are approved in the final version of the annual defense policy bill, and appropriators concur in their own defense-spending bill, this would be a win for General Electric, as it’s been lobbying Congress to continue adaptive engine development. GE said its XA100 adaptive engine, which began testing last year, would offer more thrust while burning less fuel.

“We appreciate the leadership of both Chairman Rogers and Ranking Member Smith, who recognize the importance of investing today in technology that will provide our warfighters with revolutionary capabilities in the face of growing geopolitical threats—capabilities our XA100 engine stands ready to deliver," a GE Aerospace spokesperson said in a statement.

Pratt, a subsidiary of Raytheon, also wins as the bill would fund a Pratt-led team pursuing its own adaptive engine, in addition to funding the engine upgrade program. 

“We appreciate the HASC reaffirming and not delaying the Department of Defense’s decision to support the F135 Engine Core Upgrade as the safest, lowest risk and most cost-effective F-35 propulsion solution for the warfighter and taxpayer. No other engine option will ever work on all variants of the F-35 or exceed Block 4 needs starting in 2028,” said Jeff Shockey, senior vice president of global government relations for Raytheon Technologies.

The legislation also includes provisions about U.S. Space Command—jumping into the years-long, highly political debate over the potential move of the command’s headquarters from Colorado to Alabama. Rogers’ version of the bill halts the construction or modification of Space Command facilities and freezes half of the Air Force secretary’s travel budget until he sends Congress a report on the justification for the selection of a permanent location for the headquarters. 

A recommendation to move the command from Peterson Air Force Base in Colorado Springs to the Army’s Redstone Arsenal in Huntsville was made by then-Air Force Secretary Barbara Barrett just one week before she resigned at the end of the Trump administration. 

Chairman Rogers wants the Air Force to make a decision, the aide said. 

“What I think we found out through the process over the last two few years while we're waiting for the Air Force to actually make a decision, is that the Space Command and the Air Force have been signing leases and building out infrastructure in Colorado,” the aide said. “I think the chairman's view is: why should you be using taxpayer dollars to build up all this infrastructure when the Air Force made a decision, it has been reviewed by two different reviewers and found that Huntsville, Alabama won, and won fairly.”

Correction: An earlier version of this report gave the wrong amount requested by the Air Force for the ECU program in 2024.