LONDON — After encountering delays in the F-35 upgrade known as Technology Refresh 3, or TR-3, the jet’s producer Lockheed Martin expects to complete its Block 4 modernizations by 2032 at the latest, according to senior company representatives.
“TR-3 is a new foundation to move forward Block 4 integration that started in 2018 and will continue until 2030 or 2032, so for another five to seven years,” Jim Post, the director of the manufacturer’s F-35 Partner Customer Program, told Defense News at the 2025 DSEI UK show in London.
The F-35’s hardware and software upgrade effort, known as Block 4, is designed to boost the fighter jet’s weapons capabilities, sensors and sensor fusion. As of September 2025, it was at least $6 billion over budget and years behind schedule, which was partly due to delays with the implementation of TR-3.
“Block 4 means the aircraft’s evolution, and TR-3 makes the F-35 as much as 25 times faster. It gives the jet’s systems a much improved memory, and its tactical displays for pilots are capable of implementing all processes at a faster speed,” Post said.
As the F-35 Joint Strike Fighter program is struggling with cost overruns, manufacturing delays and supply chain bottlenecks, the U.S. Government Accountability Office said in a Sept. 3 statement the “program plans to reduce the scope of Block 4 to deliver capabilities to the warfighter at a more predictable pace than in the past.”
The delayed TR-3 which is critical to the Block 4 modernization effort “was the primary driver of late aircraft deliveries in 2024,” according to the GAO. Last year, Lockheed Martin “delivered 110 aircraft. All were late by an average of 238 days, up from 61 days in 2023.”
Under the plan, dedicated operational tests for the TR-3 upgrades are to begin in the U.S. in mid to late fiscal 2026, allowing to verify if the technology refresh is operationally effective.
Editor’s note: The story has been updated to clarify Lockheed Martin expects the Block 4 modernizations to be done by 2032.
Jaroslaw Adamowski is the Poland correspondent for Defense News.
