Millions of dollars in US government incentives are being wasted to rectify delivery delays for the F-35 multirole aircraft, according to an assessment from the Government Accountability Office (GAO), a public spending watchdog.
The Department of Defense (DoD) awarded the aircraft builder, Lockheed Martin, and F135 engine maker, Pratt & Whitney, billions to deliver the most sophisticated platform in the world. But in an effort to help both primes reduce delays, concerning upgrades through the Block 4 modernisation package, the government continues to provide incentives while the delays continue to worsen.
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For instance, the GAO found that in 2024, Lockheed delivered 110 aircraft; all of them were late by an average of 238 days, up from 61 days in 2023.
Block 4 status
The Block 4 package comprises hardware and software modernisation upgrades to the F-35 Lightning II aircraft, known globally as the Joint Strike Fighter (JSF).
Ultimately, Block 4 addresses new threats to the aircraft since the DoD’s original requirements more than two decades ago. These Block 4 capabilities require more power and cooling than anticipated, which has prompted the government to modernise the overworked F135 engine.
Notably, Lockheed’s Technology Refresh 3 – a $1.9bn suite of hardware and software upgrades that are critical to the Block 4 modernisation effort – was the primary driver of late aircraft deliveries in 2024.
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By GlobalDataAt present, costs are over $6bn more and completion is at least five years later than original estimates, meaning they will not be ready until 2031. Now, there are plans to reduce the scope of Block 4 to deliver capabilities to users at a more predictable pace than in the past.
The delays have ramifications for US allies too, with the UK Ministry of Defence uncertain when it can intgerate SPEAR 3, a 100kg air-launched surface strike cruise missile, onto British F-35Bs. It is worth noting there are 20 global JSF participants and over 1,185 aircraft deliveries as of June.
Yet, all the while, Lockheed Martin executives Greg Ulmer and J. R. McDonald assured a media gathering that Block 4 will comstitute the “most aggressive update” during the Paris Air Show 2025.
GAO recommends simulation and digital tools
The GAO’s work on leading practices for product development has found that leading companies employ an iterative process of design, validation, and production to quickly develop and deliver products.
While the programme is implementing some aspects of these practices, the watchdog advises that the programme would benefit from expanding the use of modern design tools. This includes digital models and twins that developers can test in a simulated environment to more rapidly deliver capabilities to the user than it has historically.
