by DAN WARD

Forget the enormous cost overruns.

Excuse the epic schedule delays.

Overlook the disturbing performance limitations.

Let’s assume the Pentagon somehow comes up with enough money to pay for the F-35 Joint Strike Fighter. Suppose further the F-35 eventually passes all its test and evaluation milestones and the appropriate authorities make the appropriate Initial Operational Capability and Final Operational Capability declarations.

Let’s imagine a future in which the various services have patiently waited long enough to finally take ownership of their respective fleets, totaling some 2400+ aircraft, allowing the Pentagon to retire the F-16, A-10, F-18 and AV-8. And maybe the F-15 and F-22, as well.

Let’s also assume our allies get their stealth fighters too, replacing whatever old jets they’re currently flying. While we’re on a roll, why not assume our adversaries don’t make any hostile moves that would require a JSF-based response before we’re ready, and that no new threats or technologies emerge which would render the JSF obsolete or irrelevant.

Let’s assume everything works out in JSF-land and things go as well as they possibly can.

Despite these optimistic assumptions, this best case scenario for the F-35 still contains a rather significant flaw, an elephantine turd in the proverbial punchbowl. It comes down to a single word — hypoxia.

See, the U.S. Air Force grounded its F-22 stealth fighter fleet in May 2011 because pilots were displaying strangulation-like hypoxia symptoms at a rate nine times higher than the crews of other fighter jets. The grounding lasted for four months, during which time “the most capable aircraft in the world” was unflyable.

Then the secretary of defense stepped in and lifted the grounding while establishing tight restrictions on how pilots could fly the jet — not because engineers had isolated and solved the problem, but because if the situation had lasted much longer, the pilots would have lost their certifications, leaving the Air Force with a fleet of unusable aircraft and a cadre of unqualified pilots.

That sounded like a bad idea to everyone, so officials allowed the pilots to return to flight despite the lingering problem. In February, 2012 the Air Force grounded the fleet again — for the fifth time.

The good news is that repeatedly grounding the Raptor had virtually no impact on America’s defense posture, because the jet was not relevant to the military’s operations in places like Iraq, Afghanistan and Libya — at least according to then-secretary of defense Robert Gates.

The non-impact of the F-22’s non-availability surely reveals something about the value of that particular jet, but that’s a topic for another day. Instead, let’s consider what will happen when we discover a similar flaw in the F-35, some malfunction that renders the JSF unable to fly safely … and necessitates a fleet-wide grounding or five.

The key phrases here are “when” and “fleet-wide,” although “five” is a pretty significant number as well. It may be worth noting that the groundings have already begun.

Bear in mind grounding a fleet is not unheard of — the USAF sidelined its F-15s in 2007 after one of them fell apart mid-flight. But the impact of that grounding was softened by the variety of alternative aircraft, such as the F-16 and F-18.

Things would be different in our future scenario where the F-35 is essentially the only game in town. If the F-35 gets grounded in 2030, a major portion of the Air Force, Navy and Marines would all be unflyable. So would our allies. That just might be a big deal.

The world’s air forces seem to be putting an awful lot of eggs in a single basket, and those eggs are looking pretty fragile. The likelihood of the JSF displaying a flaw similar to the F-22’s is high because the JSF is just as complex as the F-22, if not more so, and all that complexity tends to hide bugs and problems and flaws.

Complexity causes fragility, as the F-22 has so cleverly demonstrated. While the F-22 represents a small portion of America’s air power, if things go according to plan the F-35 will essentially be America’s air power.

Perhaps the truly best scenario for the Joint Strike Fighter is for it to follow in the footsteps of the F-22 and provide a combat capability that is irrelevant to actual military needs. That way, when the whole fleet gets grounded because of an unsolvable flaw, the impact on our defense posture would be nil. We’ll just use drones and A-10s and cyberpower and boots on the ground to get the job done.

But if that’s the best case scenario, can someone tell me why we’re building this thing?

Dan Ward is a retired USAF lieutenant colonel. He is the author of FIRE: How Fast, Inexpensive, Restrained and Elegant Methods Ignite Innovation.