{"id":1898,"date":"2026-03-25T10:20:46","date_gmt":"2026-03-25T10:20:46","guid":{"rendered":"https:\/\/zephyrsys.us\/index.php\/2026\/03\/25\/dote-says-no-combat-capable-tr-3-configured-f-35s-were-delivered-in-fy2025\/"},"modified":"2026-03-25T10:20:46","modified_gmt":"2026-03-25T10:20:46","slug":"dote-says-no-combat-capable-tr-3-configured-f-35s-were-delivered-in-fy2025","status":"publish","type":"post","link":"https:\/\/zephyrsys.us\/index.php\/2026\/03\/25\/dote-says-no-combat-capable-tr-3-configured-f-35s-were-delivered-in-fy2025\/","title":{"rendered":"DOT&E Says No Combat-Capable TR-3-Configured F-35s Were Delivered in FY2025"},"content":{"rendered":"

\"F-35<\/p>\n

The latest Director, Operational Test & Evaluation report says no combat-capable F-35 TR-3 aircraft have been delivered to the U.S. military until September 2025 because of the truncated software.<\/h2>\n

The recently released 2025 Director, Operational Test & Evaluation (DOT&E) annual report<\/a> brought another update to the long saga of the F-35\u2019s Technology Refresh 3<\/a> (TR-3) hardware upgrade. TR-3 is the backbone upon which the new Block 4 is based, allowing the introduction of new advanced capabilities on the F-35 Lightning II.<\/p>\n

A New Catch<\/h3>\n

As we previously reported, TR-3 had already caused many issues for the F-35 program, including a lengthy halt in deliveries. The halt, which lasted from July 2023 to July 2024, reportedly saw up to 110 aircraft placed in storage before the F-35 Joint Program Office (JPO) allowed deliveries to resume.<\/p>\n

The backlog of the deliveries<\/a> was cleared in May 2025, although we have now discovered a catch through the 2025 DOT&E report. These first TR-3-configured F-35s are, in fact, non-combat-capable.<\/p>\n

\u201cNo combat-capable TR-3 aircraft have been delivered to the U.S. Services to date,\u201d says the report. \u201cAs of the end of September 2025, 158 F-35s had been delivered in the TR-3 configuration and a total of 812 aircraft (any configuration) have been produced and delivered to the U.S. Services.\u201d<\/p>\n

\"combat-capable<\/a>
The 461st FLTS, F-35 Integrated Test Force, at Edwards Air Force Base in California received a newly instrumented F-35A aircraft in 2025. (Image credit: Courtesy photo via 412th Test Wing)<\/figcaption><\/figure>\n

The cause of this new issue appears to be the truncated version of the software<\/a> that was developed \u201cby disabling some of the combat capabilities that had already been fielded on the TR-2 aircraft.\u201d This was done \u201cin an effort to stabilize the performance on the new TR-3 hardware\u201d and allow the deliveries to resume.<\/p>\n

This does not mean that the aircraft are unusable, but rather they have a limited set of capabilities which would restrict them to testing and training efforts. Specifically, the wording used in the report suggests that these aircraft feature the new capabilities introduced by TR-3 and most, but not all, of the capabilities of the TR-2.<\/p>\n

This might have been done purportedly to allow personnel to begin training<\/a> on the new variant without hampering combat readiness. Meanwhile, development and testing would continue to solve the remaining issues, with the missing capabilities gradually retrofitted in the TR-3 aircraft already delivered.<\/p>\n

The full set of capabilities introduced by TR-3 has not been disclosed for obvious reasons. However, the DOT&E report explicitly mentions the new software upgrades currently being tested include \u201cnew Electromagnetic Warfare capability enabled by upgraded hardware on TR-3 aircraft starting in production lot 19.\u201d<\/p>\n

\"combat-capable<\/a>
An F-35A with the 461st Flight Test Squadron, 412th Test Wing, conducts a TR-3 AIM-120 live fire mission over the Pacific Test Range on January 22, 2025. (Image credit: Courtesy photo via 412th Test Wing)<\/figcaption><\/figure>\n

\u201cThe TR-3 avionics upgrade, which includes upgraded main mission computers (referred to as integrated core processors), aircraft memory system, and panoramic cockpit displays, is a key enabler for new Block 4 mission systems capabilities,\u201d adds the report. \u201cThe TR-3 upgrade replaces the corresponding TR-2 components that are currently fielded in nearly the entire fleet of F-35 aircraft.\u201d<\/p>\n

What\u2019s the Real Story Here?<\/h3>\n

While the DOT&E might sound alarming, it is important to note that the one we can access is the public version and thus we do not have many of the details which fully describe the situation. In fact, those are included in the classified<\/a> report delivered to the Pentagon.<\/p>\n

Without those details, an objective analysis can\u2019t be done as it would easily become pure speculation. Additionally, as mentioned in the report, the information is not up to date, as figures are counted until the end of September 2025 and we do not have confirmation whether combat-capable TR-3 configured F-35s have been delivered after that date.<\/p>\n

Playing down the TR-3-related problems as they are attributed to software is also not ideal, as the F-35 has long been said to run on over 8 million lines of code<\/a>. Thus, considering that the F-35 is a software-defined weapon system, any modification to the software\u2019s code must be engineered to be sure it does not interfere with other lines, something that\u2019s easier said than done.<\/p>\n

\"F-35<\/a>
An F-35A Lightning II takes off from an undisclosed location in support of Operation Epic Fury. (U.S. Air Force Photo)<\/figcaption><\/figure>\n

Even with the issues around the TR-3 program, it should be remembered that the F-35 is already operational and on the frontlines. The Lightning II has long been used by the U.S. and foreign operators in real missions, proving the maturity of the platform.<\/p>\n

For instance, the F-35 saw extensive use during this year\u2019s operations against Venezuela<\/a> and Iran, just to mention the most recent ones. The 5th gen fighter has been operating against high-end air defense networks in the Suppression\/Destruction of Enemy Air Defenses (SEAD\/DEAD) role \u2013 its primary mission set \u2013 as well as other missions.<\/p>\n

Thanks to its capabilities, the F-35 has been described as a critical asset in the lineup of the U.S. military. Moreover, no F-35s have been lost in combat due to enemy action, and the only one reportedly hit by enemy fire<\/a> was able to safely return back for an emergency landing at a friendly air base.<\/p>\n

This brings us back to the initial consideration: should this really be alarming? The numbers provided by the DOT&E indicate that the aircraft affected by the issue are approximately 20% of the entire U.S. fleet, with over 650 jets not affected meaning that, even with a mission capable rate of roughly 50%, over 300 F-35s would always be ready for use.<\/p>\n

\"\"<\/a>
An F-35C Lightning II on the deck of the USS Abraham Lincoln on Mar. 3, 2026, with an array of air to surface weaponry in the foreground. Weapons include JDAMs, AGM-84K SLAM-ER, and AGM-114 Hellfire guided missiles. (U.S. Navy photo)<\/figcaption><\/figure>\n

Additionally, the F-35 has a global fleet of over 1,300 aircraft which already passed the one million flight hours milestone<\/a>. This already speaks volumes about the platform\u2019s maturity.<\/p>\n

Development and Testing Challenges<\/h3>\n

While the aircraft in the new configuration are being delivered, the testing of the Technology Refresh 3 is still in progress. This is being managed by the United Operational Test Team (UOTT), which includes personnel from the United States, the United Kingdom<\/a>, and Australia.<\/p>\n

\u201cThroughout FY25, the F-35 development effort continued to face challenges in delivering reliable, fully functional software to the operational test (OT) teams,\u201d says the DO&E report. As previously mentioned, the stability and reliability of the software were among the main issues that slowed the fielding of TR-3.<\/p>\n

\u201cThe development teams focused on two software variations, one each for the Technology Refresh (TR)-2 and TR-3 hardware configurations,\u201d continues the report. \u201cIn spite of the TR-3 capability being a rehost of TR-2, the latest iteration of TR-3 software (40R02) was unsuitable for dedicated OT. Similarly, the latest version of TR-2 software (30R08) \u2013 intended to be the last version of software fielded on the TR-2 aircraft \u2013 was predominantly unusable for additional OT events during most of FY25, due to stability problems, shortfalls in capability, and on-going discovery of deficiencies.\u201d<\/p>\n

\"\"<\/a>
A civilian maintainer assigned to the 461st Flight Test Squadron, F-35 Integrated Test Force, helps launch an F-35A aircraft for an early morning test mission over the Mojave Desert on August 5, 2024. (Image credit: Courtesy photo via 412th Test Wing)<\/figcaption><\/figure>\n

This appears to be the consequence of other problems outside of the software\u2019s development, which slow down the Operational Testing<\/a> (OT). In turn, this slows down the discovery of new problems and their solution, increasing the overall time needed to fix the issues with TR-3.<\/p>\n

\u201cThe F-35 Joint Program Office (JPO) planned for needed modifications to OT aircraft, but resource shortfalls have not enabled timely delivery of these modifications,\u201d explains the report. \u201cCurrent aircraft forecasts show that there will not be enough OT aircraft available to accomplish dedicated OT in representative formations of aircraft.\u201d<\/p>\n

The wording appears to point to a lack of instrumented aircraft<\/a> available for the testing of new software, rather than longer development timelines. As consequence of this situation, the DOT&E says it \u201ccontinues to have concerns about the ability of the United Operational Test Team (UOTT) [\u2026] to conduct adequate testing of the Block 4 capabilities because of the reduced number of OT aircraft with the necessary hardware configurations and the required instrumentation to test mission systems and weapons integration.\u201d<\/p>\n

A better idea of the situation is later provided with the number of aircraft. \u201cFunding and contracting delays have made it difficult for the OT teams to have eight fully capable aircraft available for dedicated OT trials during the OT periods,\u201d says the report. \u201cGiven OT aircraft availability rates, this generally means a total of 12 OT aircraft must be planned and funded to ensure 8 OT aircraft are available for most missions.\u201d<\/p>\n

\"\"<\/a>
Test pilots with the 461st Flight Test Squadron, 412th Test Wing, return to Edwards Air Force Base, California, on January 21 after conducting a TR-3 AIM-120 live fire mission over the Pacific Test Range. (Image credit: Courtesy photo via 412th Test Wing)<\/figcaption><\/figure>\n

The report, speaking about the testing of the last planned TR-2 software version, sheds some light on the types of open-air tests being conducted. Among these are:<\/p>\n