Lockheed Martin has announced the successful completion of the Technology Refresh 3 (TR-3) modernisation developed for the fifth-generation F-35 Lightning II fighter jet. The company stated that the TR-3 system has now reached a stable configuration capable of supporting combat missions. The announcement was made during the 2025 Paris Air Show.
J.R. McDonald, Vice President of Business Development for the F-35 Program at Lockheed Martin, confirmed that the TR-3 system has reached operational stability and is functioning reliably. However, the company did not provide a specific timeline for certification and operational approval from the U.S. government. The F-35 Joint Program Office (JPO) also did not disclose a completion schedule.
Delayed Rollout: TR-3 Deliveries Halted in 2023
Initially planned for field deployment in April 2023, the TR-3 upgrade faced delays due to challenges in software and hardware integration. Deliveries were halted in July 2023. During this period, Lockheed Martin continued production, resulting in over 120 TR-3-equipped jets awaiting delivery.
75 Technical Enhancements and AI-Compatible System
TR-3 serves as the foundation for the Block 4 modernisation program, which includes upgrades to radar, sensors, electronic warfare, and weapon systems. Featuring a next-generation integrated core processor that is 25 times more powerful than the TR-2, TR-3 also brings enhanced cockpit displays, expanded memory capacity, and rapid mission data updates.
Thanks to its advanced architecture, the system is fully compatible with next-generation capabilities such as AI-assisted mission planning and data fusion. TR-3 will serve as the baseline for Block 4 capabilities, expected to be deployed in the second half of the 2020s.
Block 4: The Most Comprehensive F-35 Upgrade to Date
Lockheed Martin describes Block 4 as “the most ambitious fighter jet modernisation in history.” This phase will integrate the AN/APG-85 radar, AIM-260 JATM, Meteor missile, AARGM-ER, Norwegian-made JSM, improved stealth coatings, and new electro-optical systems into the F-35.
Additionally, the ThNDR infrared countermeasure system and core upgrades to the Pratt & Whitney F135 engine aim to deliver 50% more thrust and cooling capacity. The XA100 engine developed under the AETP program was not selected due to cost and integration risks.
Deliveries Resume Gradually
As of July 2024, Lockheed Martin began delivering the first F-35A aircraft equipped with a limited version of the TR-3 software suitable for training missions. The first two jets were delivered to Dannelly Field in Alabama and Nellis Air Force Base in Nevada. These platforms are not yet ready for combat operations. The full Block 4-compatible version is expected to be operational by mid-2025.
By June 2025, a total of 200 TR-3-equipped aircraft had been delivered. The company aims to increase this figure by an additional 170 to 190 units by the end of the year.
Lot 20 Contract and Enhanced Production Line
The $869.9 million Lot 20 contract signed with the U.S. Department of Defense in November 2024 launched a new production phase incorporating TR-3 and Block 4 features. As of March 2024, Lockheed Martin’s production rate reached 20 aircraft per month. To maintain production during the delivery pause, the company invested $700 million of internal resources.
Additionally, upgrade kits for TR-2-configured F-35s were rolled out and are being integrated by technical teams at operational bases.
Flight Testing and Operational Milestones
The first TR-3-configured F-35 conducted its test flight on 6 January 2023 at Edwards Air Force Base, reaching an altitude of 35,000 feet and speeds near Mach 1. In multi-domain operation tests, a Dutch F-35 provided high-precision targeting data to a ground-based artillery unit.
Growing European Involvement
As of June 2025, more than 1,185 F-35s have been delivered worldwide, with 20 countries participating in the programme. European contributors to the production chain include Germany (Rheinmetall), Finland (Patria), Italy (Leonardo), and Belgium. Component assembly is carried out at the Cameri facility in Italy.
Most recently, Poland became the latest European country to receive TR-3-equipped F-35s. Polish pilots began their training at Ebbing Air National Guard Base in the U.S. The Czech Republic, Romania, and Greece are also among the new customers.
Investing in the Future: Beyond the Fifth Generation
Lockheed Martin aims to future-proof the F-35 by integrating technologies developed under the U.S. Next Generation Air Dominance (NGAD) program. The platform will adopt new stealth coatings, advanced sensors, and optional unmanned flight capabilities under the “fifth-gen plus” concept.
The company claims that this new configuration could deliver 80% of sixth-generation capabilities at approximately half the cost. A new twin-engine concept dubbed “F-55” is also under consideration, though some experts question the project’s feasibility.
Aero Haber You can follow X-Twitter account. Follow
