This article originally appeared at thedailybeast.com

American fighter planes are the fastest, most maneuverable jets in the world. But their weapons are becomingly increasingly obsolete—and that has some in the U.S. Air Force spooked.

High flying and fast, the F-22 Raptor stealth jet is by far the most lethal fighter America has ever built. But the Raptor—and indeed all U.S. fighters—have a potential Achilles’ heel, according to a half-dozen current and former Air Force officials.

The F-22’s long-range air-to-air missiles might not be able to hit an enemy aircraft, thanks to new enemy radar-jamming techniques.

The issue has come to the fore as tensions continue to rise with Russia and a potential conflict between the great powers is once again a possibility—even if a remote one.

“We—the U.S. [Department of Defense]—haven’t been pursuing appropriate methods to counter EA [electronic attack] for years,” a senior Air Force official with extensive experience on the F-22 told The Daily Beast. “So, while we are stealthy, we will have a hard time working our way through the EA to target [an enemy aircraft such as a Russian-built Sukhoi] Su-35s and our missiles will have a hard time killing them.”

The problem is that many potential adversaries, such as the Chinese and the Russians, have developed advanced digital radio frequency memory (DRFM) jammers. These jammers, which effectively memorize an incoming radar signal and repeat it back to the sender, seriously hamper the performance of friendly radars.

Worse, these new jammers essentially blind the small radars found onboard air-to-air missiles like the Raytheon AIM-120 AMRAAM, which is the primary long-range weapon for all U.S. and most allied fighter planes.

That means it could take several missile shots to kill an enemy fighter, even for an advanced stealth aircraft like the Raptor. “While exact Pk [probability of kill] numbers are classified, let’s just say that I won’t be killing these guys one for one,” the senior Air Force official said. It’s the “same issue” for earlier American fighters like the F-15, F-16, or F/A-18.

Another Air Force official with experience on the stealthy new F-35 Joint Strike Fighter agreed.

“AMRAAM’s had some great upgrades over the years, but at the end of the day, it’s old technology and wasn’t really designed with today’s significant EA in mind,” this official said.

Like boxers, every missile has a reach, a range, a limit to how far it can hit. In the not-too-distant future, the AMRAAM might also be out-ranged by new weapons that are being developed around the world. Particularly, Russia is known to be developing an extremely long-range weapon called the K-100 that has far better reach than anything currently in existence.

“While we are stealthy, we will have a hard time targeting Russian Su-35s and our missiles will have a hard time killing them.”

The problem is not a new one. Historically, the Pentagon has always prioritized the development of new fighters over the development new weapons—it’s a uniquely American blind spot. During the 1970s, the then brand new F-15A Eagle carried the same antiquated armament as the Vietnam-era F-4 Phantom II.

It wasn’t until the 1990s that the F-15 received a weapon in the form of the AMRAAM that could take full advantage of its abilities.

The same applies to short-range weapons—it wasn’t until the early 2000s with the introduction of the AIM-9X that the U.S. had a dogfighting weapon that could match or better the Russian R-73 Archer missile.

The Air Force officials all said that some of the American missiles would get through during a fight—there is no question of that—but it would take a lot more weapons than anyone ever expected. The problem is that fighter aircraft don’t carry that many missiles.

The Raptor carries six AMRAAMs and two shorter range AIM-9 Sidewinder missiles inside its weapons bays. At the moment, the F-35 carries only four AMRAAM missiles inside its weapons bays, but that might be expanded to six in the future.

Older fighters like the Boeing F-15 Eagle carry no more than eight missiles—while the F-16 usually carries no more than six weapons.

That means that if a fighter has to fire—for instance—three missiles to kill a single enemy fighter, the Pentagon is facing a serious problem.

“Getting a first shot is one thing,” said a former Air Force fighter pilot with extensive experience with Russian weapons. “Needing another shot when you have expended your load is another when your force structure is limited in terms of the number of platforms available for a given operation.”

There are some potential solutions, but all of them mean spending more money to develop new missiles. former Air Force intelligence chief Lt. Gen. Dave Deptula said it’s “critical” that the U.S. and its allies move “air-to-air weapons into a future where they can effectively deal with adversary electronic attack.”

One relatively simple fix would be to develop a missile that picks out its targets using radars with a completely different frequency band. Current fighter radars and missiles operate on what is called the X-band, but they don’t necessarily have to. “Getting out of X band is on option,” said one senior Air Force official.

The Pentagon could also develop a new missile that combines multiple types of sensors such as infrared and radar into the same weapon—which has been attempted without much success in the past.

Right now, the Defense Department—led by the Navy—is working to increase the range of the AIM-9X version of the Sidewinder by 60 percent to give the Pentagon’s fighter fleet some sort of counter to the jamming problem. But even with the extended reach, the modified Sidewinder won’t have anywhere close to the range of an AMRAAM.

The other option is to stuff fighters like the F-22 and F-35 with more missiles that are smaller. Lockheed Martin, for example, is developing a small long-range air-to-air missile called the “Cuda” that could double or triple the number of weapons carried by either U.S. stealth fighter.

“Look to a new generation of U.S. air-to-air missiles, like Cuda, to neutralize any potential numerical advantage,” one senior industry official said.

The industry official said that despite the small size, new weapons like the Cuda can offer extremely impressive range because it doesn’t have an explosive warhead—it just runs into the target and destroys it with sheer kinetic energy.

But the senior Air Force official expressed deep skepticism that such a weapon could be both small and far-reaching.

“I doubt you can solve range and the need for a large magazine with the same missile,” he said.

This official added that future weapons would be far better at countering enemy jamming—so much so that future fighters will not need to have the sheer speed and maneuverability of an aircraft like the Raptor. “I think top end speed, super cruise, and acceleration will all decline in importance as weapons advance in range and speed,” he said.

For a military that’s committed hundreds of billions of dollars to such advanced fighters, such developments might not exactly be welcome news.