I thought I’d start an entirely new thread to discuss the F-35 versus the Gripen so as to not hijack the submarine thread where some of the stuff has been discussed. We had spirited discussions about Gripen vs. F-35 in the old DSLReports forums.
The version of the F-35 Canada has contracted for is called the Block 4 model. It is in deep trouble right now.
The F-35’s critical Block 4 upgrade package is now five years behind schedule, expected in 2031, and $6 billion over budget, according to a scathing US Government Accountability Office (GAO) report.
The update includes over 75 major improvements like increased missile capacity and advanced electronic warfare.
Facing these massive delays and cost overruns, the F-35 program now plans to reduce the scope of the vital Block 4 modernization.
Why the F-35 Fighter Block 4 Upgrade Is Slipping
The Pentagon’s modernization program for its flagship fifth-generation fighter, the F-35 Lightning II, is in trouble.
The long-planned Block 4 upgrade, intended to equip the jet with new weapons, sensors, and computing power, is now running years behind schedule and billions of dollars over budget.
The Block 4 package is central to keeping the F-35 effective against emerging threats from China and Russia, whose advanced aircraft and integrated air defenses are closing the technological gap with the West.
Without this program, the jet risks falling behind before the next war even starts.
UNDERSTANDING THE BLOCK 4 UPGRADE
In fighter jet terms, a “block” refers to a generation-wide package of hardware and software improvements.
Block 4 is designed to deliver expanded weapons options, improved electronic warfare systems, and next-generation networking and sensor fusion—all aimed at maintaining air dominance well into the 2030s.
The upgrade depends on the Technology Refresh 3 (TR-3) – a step that preceded the upgrade and outlines plans for installing a new computer in the plane, along with the software architecture that will power it and handle all the added capabilities that come with Block 4. Without TR-3, Block 4 simply cannot function.
The original idea was that TR-3-equipped jets would have rolled off the production line in 2024, paving the way for a full modernization some two years later—but software integration issues have substantially slowed TR-3 deliveries.
Originally, Block 4 promised more than 60 new capabilities for the jet—from the ability to fire longer-range air-to-air missiles to carrying new precision bombs internally. The upgrade would also include new radar systems and electronic-attack capabilities, as well as improvements to data sharing with other aircraft and network - much of which the Gripen E already has.
Together, the improvements are designed to turn the F-35 into a networked combat hub that shares information and improves situational awareness, as well as a formidable stealth fighter - much of which the Gripen E already has - except the stealth bit.
But if Canada is not a First-day-of-war combatant, which it is unlikely to be, then stealth is not as critical an issue for us as we are not going to be the ones beating back an adversaries air force In the first instance. Most of our effort is going to be done for sovereignty patrol on all our coasts, and possibly ground attack, Events in Ukraine show some of the futility of conventional ground attack aircraft of any type versus portable missile air defense systems, and much of the ground attack role has been taken over by long range missiles and a myriad of drones. More than likely, the bulk of our use will be maritime patrol and interdiction.
THE DELAYS, COSTS, AND CAUSES
According to the GAO, Block 4 costs have ballooned by more than $6 billion since the last estimate, bringing the total expected price tag to around $16.5 billion.
Completion is now expected at least five years later than initially planned.
First, there are the TR-3 delays. Hardware and software integration problems in Technology Refresh 3 have prevented the F-35’s onboard systems from running the new Block 4 applications. Until those computers are certified and fixed, the new jets cannot be delivered with full capability.
There are worsened supply chain issues. that are contributing significantly more than previous delays.
Then there’s the issue of power and cooling constraints. The additional electronics and weapons envisioned for the Block 4 upgrade require more power—and therefore more cooling. The current Pratt & Whitney F135 engine cannot fully support the new system without an upgrade program of its own, and that planned upgrade has been delayed until around 2031.
The currently cut-backed version of Block 4 will include only a fraction of the original 66 capabilities, with the rest deferred for future increments of the upgrade. And this carries serious consequences. For F-35 operators, it means a growing capability gap. Without Block 4, the F-35 cannot integrate some of its most advanced new munitions and datalink systems that would allow this fifth-generation platform to counter next-generation Chinese and Russian defenses. Did I mention that Gripen E already has this operational and baked into its DNA?
With every delay in the F-35, allied countries suffer setbacks to their operational plans, thereby complicating interoperability and increasing costs for training, sustainment, and logistics.
I will fault Trudeau for not choosing the Gripen five years ago. By this point in time we would’ve had production happening in Canada, and our factory most likely would be contributing aircraft to Ukraine and other customers within a year or two of today. Having our own production line means that maintenance, repair, and overhaul could easily be done domestically.
Canada has had a long history of both design development and productionOf indigenous aircraft, as well as production of fighter aircraft under license, Most notably, the F-86 Sabe and the F104 Starfighter. The Canadian produced Sabres and Starfighters were widely recognized as being better built than the ones produced in the United States.