US Air Force F-35A Lightning II. F-35 deliveries with TR-3 upgrades are scheduled to begin as soon as April 2024. (US Air Force/Staff Sgt Zade Vadnais)

Lockheed Martin has flown the first production F-35s equipped with Technology Refresh 3 (TR-3) hardware and software upgrades, the manufacturer confirmed on 28 November. F-35 deliveries to customers have been paused until TR-3 is judged to be sufficiently mature.

“We are now flying TR-3 software on F-35 production jets in Fort Worth and flight test continues at Edwards Air Force Base and Naval Air Station Patuxent River,” the company told
Janes
on 28 November.

The TR-3 software upgrade first flew in January 2023 aboard a US Air Force test aircraft at Edwards Air Force Base. The US Department of Defense’s F-35 Joint Program Office (JPO) declined to specify the number of F-35s flying with TR-3 today, citing operational security.

“The JPO and Lockheed Martin agree that the acceptance of TR-3 aircraft should fall in the April 2024 to June 2024 timeframe based on risks as we understand them today,” the JPO told
Janes
on 28 November.