Fleet Readiness Center East has completed the conversion of the first F-35B from TR-2 to TR-3 configuration, which will support future Block 4 upgrades.
A significant milestone has been achieved for the F-35B Lightning II as the U.S. Navy’s East Wing Readiness Center (FRC) at Marine Corps Air Station (MCAS) Cherry Point, North Carolina, completed the Technology Refresh-3 (TR-3) upgrades to the first aircraft. TR-3 lays the foundation for future Block 4 hardware upgrades.
The BF-105 and BF-88 were delivered May 14 and May 21, and “the BF-81 is expected to complete its conversion in July,” according to a press release from the F-35 Joint Program Office (JPO) on June 2, 2026. Images of BF-105 capturing FRCE crews after the TR-3 upgrade show the aircraft is assigned to Marine Fighter Attack Wing-231 (VMFA-231) “Ace of Spades,” part of Marine Aircraft Group 14 (MAG 14), a component of the 2nd Marine Air Wing (MAW).
The U.S. Marine Corps is the only U.S. service that uses the F-35B, and operates a total of 122 F-35s along with the carrier-launched F-35C. Other foreign users of the short takeoff and vertical landing (STOVL) variant of the F-35 include the United Kingdom, Italy, and Japan. The release also cites FCRE as one of four global depots for F-35 maintenance repair and modifications, which include Hill AFB and Ogden in Utah, Cameri in Italy and Williamstown in Australia.
Lightning level up! ⚡️
JPO achieved a significant milestone by beginning the first conversion of the F-35B Lightning II operational aircraft from the TR-2 to the advanced TR-3 configuration.
This massive hardware and software upgrade gives the jet a significant performance boost. pic.twitter.com/8rTN1GpD0b
— F-35 Lightning II Joint Program Office (@theF35JPO) June 3, 2026
The development comes on the heels of delays to the TR-3 program for all three F-35 variants, which saw simpler versions rolled out as a stopgap measure until technical issues were resolved.
TR-3 operation in FRCE
Technology Refresh 3 (TR-3) is the “backbone” that supports future Block 4 upgrade hardware covering 75 major systems. The major upgrade is the powerful AN/APG-85 radar, which replaces the APG-81 as the primary sensor, while other upgrades include a new electronic warfare suite, an improved Electro-Optical Tracking System (EOTS), new cockpit displays, navigation and communications systems, and a next-generation Distributed Aperture System (DAS).
A new integrated core processor chip provides computing and fuses data from these sensors. Engine core upgrade (ECU) for the Pratt & Whitney F135 5th generation supercruise engine produces significant power required for the Northrop Grumman APG-85 radar and other electronics.
U.S. Air Force Lt. Col. Matthew Hawkins, logistics lead for F-35 conversion/modification within the F-35 JPO, spoke of accelerated large-scale modifications through initial conversions that will help improve the maximum speed process, with “700 aircraft already deployed annually (…) throughout the fleet.”
Hawkins noted the tremendous pace of work that supports the tactical direction of the F-35. “The faster we upgrade the jet, the more capable our warfighters will be. This is not just an engineering milestone. It’s an operational milestone. The TR-3 ensures the F-35 will remain the quarterback of the battlespace for the next decade,” he said.
Designed for dominance. ⚡
An F-35B Lightning II assigned to Marine Fighter Attack Squadron (VMFA) 121 prepares for takeoff from the flight deck of the U.S.-class amphibious assault ship USS Tripoli (LHA 7). pic.twitter.com/faPMYgLAqk
— F-35 Lightning II Joint Program Office (@theF35JPO) June 5, 2026
TR-3 Block 4 Delay
Technical problems with the TR-3 caused significant delays to the F-35 program. This halted deliveries from July 2023 to July 2024, piling up to 100 to 120 airframes at the Lockheed Martin facility in Fort Worth, Texas. With the Pentagon, JPO and Lockheed Martin agreeing to a “truncated” version of the software, deliveries resumed in 2024 and the company reported clearing the backlog by May 2025.
A scaled-down variant combining TR-3 and TR-2 features that did not affect the safety or airworthiness of the aircraft limited the aircraft’s advanced capabilities as much as possible. However, a recent Director of Operations Test and Evaluation (DOT&E) report found that none of the 158 TR-3 F-35s delivered to the United States by September 2025 are combat-capable jets, putting a question mark on the delivery backlog, which was cleared in May 2025.
A total of 191 F-35s have been delivered by the end of 2025, bringing the total number of Lightning IIs delivered to U.S. service to 812 (all configurations), according to the report. Of these, a total of 541 are F-35As.
It has been reported that due to technical development issues with the APG-85 radar, some F-35s entered service without the radar installed. The Air Force’s fiscal year 2027 budget requests $1.7 billion to convert Lot 17 and 181 older aircraft to APG-85s.
F-35B engines operate at FRCE.
FRCE also reported other milestones over the years related to the repair, overhaul and assembly of the F-35B’s unique F135 engine, which features lift fans and complex designed components. In September 2023, FRCE announced the first successful assembly of an F-35B lift fan clutch, marking the first time within the Department of Defense (DoD) this task has been performed outside of the original manufacturer’s facility.
Lift fans manufactured by Rolls-Royce for the Pratt & Whitney F135 engines provide the F-35B with unique STOVL capabilities. FRCE staff received thorough theoretical and hands-on training, including reviewing tens of thousands of engineering drawings and blueprints and studying manufacturing and assembly processes at the Rolls-Royce LiftWorks facility in Indiana.
FRCE subsequently announced that the first repair and overhaul of the F-35B’s three-bearing rotation module (3BSM) was completed in August 2025. The 3BSM is a rotating jet pipe that allows F-35B pilots to redirect engine thrust downward to generate the aft vertical lift needed for STOVL operations.
The completed 3BSM marks the first time the base has returned this component to the F-35 global supply chain supporting U.S. forces and international partners.
