US is talking about an ‘interim’ F-35 ‘between Block 3 and 4’

The F-35 Block 4 upgrade, known as Technology Refresh 3 or TR3, promised to yield significant enhancements in processing power, computer memory, and display quality. Unfortunately, as things stand, the results have not quite met the expectations of its manufacturer, Lockheed Martin, and its customers. 

US is talking about an 'interim' F-35 'between Block 3 and 4'
Photo by Aijaz Rahi / AP

While issues with the TR3 upgrade aren’t a new development, recent events have catapulted the situation into the spotlight once again. The US Department of Defense [DoD] is seen to be contemplating an introduction of an intermediary TR3 version to the fifth-generation F-35 fighter jets. This translates into a hybrid model, standing somewhere in between Block 3 and Block 4. 

This intermediate version of TR3 with undisclosed features marks a deviation from the full upgrade plan. Though it remains unclear what capabilities this ‘interim F-35’ lacks, test flights have already been conducted. As confirmed by the DoD, these tests took place last week at the Lockheed Martin facility located in Fort Worth, Texas. 

There will now be six air-to-air missiles in the F-35 'belly'
Photo credit: Aviation Week

According to definitions and assessments by American experts in recent years, the TR3 upgrade was expected to increase the payload capacity of the F-35 Block 4, translating to enhanced ammunition storage. It was also projected to improve the precision of the ammunition and further refine the electronic warfare systems. Essentially, customers were promised an F-35 that was more lethal than before. 

Delay for Belgium

Sadly, Belgium, amongst other clients, has been negatively impacted by these recent events. Initially, Belgium was set to receive two F-35 Block 4s by the end of 2023, with assembly beginning in early August. However, the Belgian Air Force declined to accept the first completed aircraft, citing non-compliance with the technical specifications of the Block 4 upgrade. 

Italy will assemble 24 of the 36 Swiss F-35 Lightning II stealth fighters
Photo credit: Il Manifesto

Despite these setbacks, Lockheed Martin remains positive, assuring that the Belgian Air Force will indeed receive the promised 34 F-35 Block 4 units. They acknowledge the issues with TR3, adding that such hiccups occur with any new upgrade worldwide. Plans are in place for the first deliveries by the first half of 2024, affirming that the problem resolution is imminent. 

The current crop of F-35 aircraft comes equipped with TR2. TR2 is produced by BAE Systems. The touted “new and improved” TR3 version is a Lockheed Martin production.

Why TR-3?

The TR-3 processor outranks the TR-2 in F-35 aircraft due to its elevated clock speed. This permits the F-35 to execute more intricate tasks while reacting swiftly to fluctuating battlefield circumstances. 

The remarkable clock speed isn’t all. TR-3 also boasts a larger cache memory than its predecessor, the TR-2. With more data stored near the processor, data access time is significantly reduced. Consequently, the F-35 can process data faster and with more efficiency. 

Another superiority of the TR-3 stems from its advanced power management features. Efficient operation, minimal power utilization, and less heat production make it the preferred option for high-performing aircraft like the F-35, ensuring extended operation periods without the worry of overheating or power shortage. 

Two European F-35 Block 4s produced turned out not to be Block 4s
Photo credit: Twitter

The TR-3 doesn’t disappoint in durability either. Built for harsh environments, it can withstand extreme temperatures, vibrations, and other forms of stress. This translates to an F-35 that runs smoothly in a wide array of conditions with less likelihood of technical glitches or field failures.


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