Two European F-35 Block 4s produced turned out not to be Block 4s

The assembly of the first two F-35As for the Belgian Air Force began at the Lockheed Martin plant in Fort Worth. According to the terms of the contract for the supply of 34 F-35A units, the first two aircraft must be ready and transferred before the end of the year.

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Photo credit: Il Manifesto

However, the Belgian Air Force refuses to accept the first finished aircraft with tail number AY-01, which has already left the final assembly line. According to the Belgian military department, the first two AY-01 aircraft and the AY-02 being completed do not meet the technical requirements of the Block 4 modification.

It is noted that in the purchase contract, it was specified that the aircraft would be delivered in the most modern version available. Currently, the latest modification is the Block 4 version, with which the F-35A should receive many new features.

This modification includes a new TR-3 integrated core processor with higher processing power, a panoramic cockpit display, an improved memory unit, new radar, an electronic warfare system, the ability to use modern weapons, and other upgrades.

TR-2 instead of TR-3

Two European F-35 Block 4s produced turned out not to be Block 4s
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According to an advertisement from Lockheed Martin, these upgrades will make the stealth aircraft more resilient to modern ground and air threats, in both offensive and defensive missions. Work is currently underway to further integrate and certify the TR-3 processor, which will take longer than previously expected.

The installed processor of the previous generation TR-2 does not have the necessary power reserve for the new Block 4 modification. Now it is planned that all work on the new version will be completed in the second quarter of 2024.

The Belgian Air Force will not accept F-35A fighters until their upgrade to the Block 4 version with the TR3 processor is completed, and until the fighter is fully tested and certified, the Belgian Ministry of Defense said.

TR-2/TR-3 differences

The TR-2 and TR-3 processors are both used in the F-35 fighter jet, but they serve different purposes. The TR-2 is responsible for handling the aircraft’s sensor data, while the TR-3 is responsible for executing the jet’s mission software. This division of labor allows for more efficient processing and better overall performance of the F-35.

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The TR-2 processor is manufactured by BAE Systems and is based on the PowerPC architecture. It is responsible for processing data from the F-35’s various sensors, including radar, electro-optical targeting system, and electronic warfare system. The TR-2 is designed to handle large amounts of data quickly and efficiently, allowing the F-35 to quickly identify and track targets in the air and on the ground.

The TR-3 processor, on the other hand, is manufactured by Lockheed Martin and is based on the ARM architecture. It is responsible for executing the F-35’s mission software, which includes flight controls, weapons systems, and communication systems. The TR-3 is designed to be highly reliable and secure, ensuring that the F-35 can complete its missions safely and effectively.

Why TR-3 is better?

The TR-3 processor is better than the TR-2 in the F-35 because it has a higher clock speed, which allows it to process information faster. This means that the F-35 can perform more complex tasks and respond more quickly to changing situations in the field.

In addition to its higher clock speed, the TR-3 processor also has more cache memory than the TR-2. This allows it to store more data closer to the processor, which reduces the time it takes to access that data. As a result, the F-35 can process information more quickly and efficiently.

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The TR-3 processor also has more advanced power management features than the TR-2. This means that it can operate more efficiently, using less power and generating less heat. This is important for a high-performance aircraft like the F-35, which needs to be able to operate for long periods without overheating or running out of power.

The TR-3 is designed to operate in harsh environments and can withstand extreme temperatures, vibrations, and other stresses. This means that the F-35 can operate in a wider range of conditions and is less likely to experience technical problems or failures in the field.

The problem was known

In truth, the problem with the TR-3 has been known for quite some time. Belgium shouldn’t be surprised, but apparently, they were aware of the problem after finding differences in processors.

The F-35 Joint Program Office has announced a possible delay in the delivery of new F-35 jets, causing difficulties for contractor Lockheed Martin. The delay is due to the Pentagon’s Block 4 project, which involves technological updates to the F-35 fleet that require prior hardware and software upgrades, known as Technology Refresh 3 (TR-3). 

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Photo credit: ViperWing

Lockheed Martin is contracted to produce nine planes per month, leading to a potential stockpile if the delay continues. Despite this, the company plans to meet the F-35s delivery commitment by December. They have declined to comment on the financial implications of the delay. 

Doug Birkey from the Mitchell Institute for Aerospace Studies has stated that the delay will cause a temporary reduction in Air Force capacity. However, he also noted the Air Combat Command’s resource management and his confidence in Lockheed Martin’s resolution of software issues. 

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The first TR-3 flight test revealed previously undetected software problems, adding to project pressures and rising costs. Yet, Birkey argues the blame for these issues can’t be solely placed on Lockheed Martin, attributing it to the structure of the Joint Program Office and the design of the program. 

Despite the challenges, Birkey is hopeful about the Block 4 upgrades. He praises them as a significant upgrade and believes they could provide solutions for Combatant commands. Greg Ulmer, Executive Vice President of Lockheed’s Aeronautics business, has confirmed that flight testing for the new configuration is currently underway.


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