After significant delays, Lockheed Martin’s Tech Refresh 3 (TR-3) upgrade for the F-35 stealth fighters appears to be nearing completion. This development represents a major leap in capabilities for these fifth-generation aircraft and paves the way for the Block IV modernization, which promises enhancements in sensors, artificial intelligence, data processing, and combat capacity—both for jets currently in service and future units operated by the U.S. Armed Forces and its allies.
Over the past months and years, the F-35 fighter program experienced delivery delays due to issues surrounding the TR-3 software upgrade. In response, Lockheed Martin rolled out a truncated version of TR-3, following the U.S. Department of Defense’s decision to pause F-35 acceptance due to the update’s delays. This version was declared safe for operations in July 2024 by Lieutenant General Michael Schmidt, director of the Joint Program Office (JPO), partially overcoming the severe setbacks caused by delays in flight testing and factory installation of the new update. U.S. fighter jets were not the only ones affected—Denmark’s case, which involved the return of its F-35s from U.S. territory, is a telling example.
Although deliveries resumed, the software remained incomplete, allowing the updated aircraft to be used only for training missions. So far, 200 F-35s with the truncated TR-3 version have been delivered, with the company now on track to produce an additional 170 to 190 aircraft by the end of 2025.
It’s worth recalling that the full TR-3 upgrade was originally expected in the coming year, and as of late 2024, more than 80 proposed modifications in communications, navigation, and electronic warfare were still not ready—costing the American company a portion of the stipulated payments. Now, after months of limited information, the release of the complete version may be closer than expected.
The update, essential for full Block IV functionality, includes a suite of sensors, improvements, and features that allow the aircraft to carry more long-range precision weapons. It will also feature enhanced electronic warfare (EW) capabilities and advanced data fusion. Additionally, the update includes hardware improvements, such as an integrated core processor with 25 times the processing power of the previous TR-2 upgrade.
“First of all, all the sensors are being dramatically improved. Secondly, there’s the ability to carry more and different types of weapons. And third—and this will be the real game-changer—are the additional interoperability functions that will allow us to communicate across domains and be that central node on the battlefield,” McDonald added.
It was also explained that the upgrade will allow the F-35 Block IV to become a “key enabler for collaborative combat aircraft in the future,” McDonald stated. This refers to the U.S. Air Force’s Collaborative Combat Aircraft (CCA) program, which aims to develop an unmanned aerial vehicle (UAV) designed to support manned fighters. The Fury models from Anduril, designated YFQ-44A, and the Gambit models from General Atomics Aeronautical Systems (GA-ASI), designated YFQ-42A, are currently undergoing ground tests, with flight tests expected to begin later this year.
Meanwhile, it should be noted that the Pentagon is reportedly planning to cut in half the deliveries of new F-35 stealth fighters intended for the U.S. Navy and Air Force. With an eye on the development of new programs—such as the future sixth-generation Boeing F-47 fighter—along with the associated costs, the Department of Defense is seeking to slow deliveries. The proposal calls for the U.S. Air Force to receive only 24 jets in 2026, instead of the previously agreed 48. The number of jets for the Navy would be reduced from 17 to 12, while the Marine Corps would see a cut of two units, though it remains unclear whether this would involve fewer F-35Bs, F-35Cs, or a combination of both.
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