A key design review for the F-35 fighter jet’s engine upgrade will happen several months later than originally predicted, as the federal government adds one other level of review to the method.
An executive for Pratt & Whitney, the RTX-owned company that makes the jet’s F135 engines, told reporters Tuesday that the Engine Core Upgrade program’s preliminary design review is anticipated to happen in May 2024.
That’s later than the corporate originally predicted last fall, when it said the review was scheduled for January 2024, a couple of month after the corporate expected to complete its preliminary design.
In a press release to Defense News on Friday, the F-35 Joint Program Office said the design review is “event driven” and has not been delayed, but that it’s taking a better have a look at the engine upgrade.
“We’ve got added a senior-level engineering and technical review to the schedule, which can happen within the February/March time-frame,” the JPO said. “The JPO, at the side of our industry partner [Pratt & Whitney], continues to mitigate risk as we work toward the PDR [preliminary design review].”
Pratt & Whitney spokesperson Heather Uberuaga said the Engine Core Upgrade program, or ECU, is on course, and referred follow-up inquiries to the JPO.
This system is meant to offer the F-35 more power, thrust and cooling ability. That might be needed for a wide-ranging slate of modernizations planned for the fighter, often called Block 4, which can allow the jet to hold more weapons in addition to improve its targeting, electronic warfare capability and sensors.
The Pentagon considered creating a wholly recent engine for the jet to offer the needed thrust, power and cooling ability, but last 12 months decided to as an alternative keep and upgrade the F-35′s current Pratt & Whitney-made F135 engines.
Jen Latka, vice chairman for Pratt’s F135 program, also told reporters the corporate is on course to complete designing the engine upgrade in mid-2025 and begin testing it the next 12 months. The ECU’s critical design review is anticipated to happen next 12 months as well.
It will allow the engine upgrade to be delivered in 2029, Latka said.
Pratt & Whitney executives have downplayed the potential danger of an prolonged continuing resolution on the ECU program’s long-term timeline. The highest officer in command of the F-35 program, Air Force Lt. Gen. Michael Schmidt, warned lawmakers in December that funding could run out for the engine upgrades inside months if a 2024 budget isn’t passed.
Latka told reporters that passing a budget is critical for ECU and other programs, and an prolonged continuing resolution for an extended time period would affect it. But, she added, it’s unlikely an extended continuing resolution would delay plans to have the engine upgrades fielded in 2029.
“There’s numerous different pieces of design which are progressing at different rates immediately,” Latka said. “We don’t have a precise date when the cash runs out and the timer goes off.”
Latka said all versions of the F-35, including the “B” variant that has a tilting version of the engine so the fighter can hover, will use essentially the identical core upgrade, although the configuration will differ for the F-35B.
Pratt & Whitney expects the technique of swapping out the engine cores for all F-35s in the sector will take about 18 months. Once the brand new engine core is prepared, Latka said, the military’s own maintainers would find a way to put in it at depots or potentially on the flight line in a couple of shifts.
“It’s not a one-shift job, but it surely’s a reasonably easy exercise,” Latka explained.
Pratt & Whitney is heavily using digital design techniques on the F135 upgrades, Latka added, which she predicted will save money and time in addition to and improve the standard of the components going into the engine. The corporate is designing all parts with a digital model, she said, and once those digital blueprints are done, the firm will send them to suppliers to construct.
The entire “digital thread” for every part may also help military services conduct preventive maintenance, Latka said. And Pratt & Whitney’s pitch for a next-generation adaptive propulsion engine will similarly use a totally digital process, she added.
Jill Albertelli, Pratt & Whitney’s president of military engines, also noted the corporate plans to check prototypes of its next-generation adaptive propulsion engine, which might go within the Air Force’s planned Next Generation Air Dominance fighter, within the late 2020s.
Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.