Software Delays Clear, Production Schedule Back On Track

Lockheed Martin has delivered, as of May 1, 2025, 72 F-35 Lightning II fighter aircraft to the Department of Defense following several months of delays in implementing the Technology Refresh 3 (TR-3), according to the Pentagon’s F-35 Joint Program Office, or JPO.

The TR-3 upgrade is a critical step in modernizing the fifth-generation aircraft with the introduction of a new core processor, enhanced displays, and open-architecture software to integrate future capabilities. Those include the soon-to-come Block 4 package.

The DoD has been withholding $5 million per jet starting in 2024 due to the delivery delays. That was lowered by $1.2 million per jet in January 2025 as the company made progress on integrating the TR-3. The majority of withheld funds will be released only incrementally going into 2026.

Lockheed relies heavily on the F-35 program, which accounts for about 30% of its annual revenue. That reliance may be on shaky ground however, as the 2026 defense budget proposal released in June 2025 reduces the F-35 procurement from 68 aircraft down to 47. The funding is being redirected toward drones, hypersonic missiles, and other advanced munitions.

The obstacles faced by the TR-3 implementation have been tied to the core integrated processor produced by L3Harris. Those issues were found in 2023 and caused the Air Force to temporarily halt deliveries and delay schedules for international customers including Denmark and Belgium.

At the latest Paris Air Show in June, Lockheed execs talked up the TR-3 as “the foundation for the most aggressive upgrade in fighter history,” by incorporating more processing power, AI enhancements, and interoperability features to keep pace with evolving threats.

The coming Block 4 package is actually a series of incremental upgrades that will take place through the late 2020s and early 2030s.

Those enhancements include:

• Sensor and radar improvements, such as the integration of the AN/APG 85 active electronically scanned array (AESA) radar
• Electronic warfare upgrades for better threat detection and survivability
• Expanded weapons options, including long-range precision strike munitions and additional guided weapons
• Interoperability improvements to enhance data-sharing across joint and allied forces

Lockheed Martin has put more than $350 million into R&D for Block 4 capabilities.

FMI:  lockheedmartin.com/