F-35 suffers continued developmental and in-service reliability problems, says Pentagon test director

US Marine Corps F-35Bs being fuelled at Tinian, Northern Mariana Islands, on 30 January 2025. (US Marine Corps)

The Lockheed Martin F-35 continues to suffer from reliability issues both in service and in testing, the US Department of Defense's (DoD's) Director, Operational Test and Evaluation (DOT&E), wrote in a new report.

The DOT&E report is an annual summary of unclassified DoD test programmes. This year's report, dated January 2025, found the F-35 programme behind schedule and suffering from software and hardware problems.

The report detailed the delay in fielding operational F-35s with the Technical Refresh-3 (TR-3) standard, which includes a new central processor and software load, among other modifications.

The software intended for TR-3 was meant to build off a new software version for the current F-35 operational standard, TR-2. The multinational test team halted testing of the TR-2 software load, designated 30R08, in February 2024, citing poor software stability and the discovery of four Category I deficiencies, “many of which were against capabilities that were working in previous versions of [the] software, an indication of insufficient integration and regression testing”, the report said.

Implementing 30R08 software in the field is two years behind its planned March 2023 date, with no new roll-out date provided.

Delays and performance issues have long plagued the F-35 programme. Previous configurations, including 30R06 and 30R07, were also delivered behind schedule and lacked some promised capabilities.