F-35 shot down, the stealth myth of fifth-generation fighters has been shattered | Military

Ask AI · How has Iran used loitering munitions to break through the F-35 stealth defense?

U.S. Air Force F-35A stealth fighter (Visual China/Photo)

On March 19, 2026 local time, the U.S. Central Command and the Pentagon confirmed that during an operational mission over Iran, a U.S. Air Force F35A was forced to abandon the mission due to a malfunction, and successfully made an emergency landing at a certain U.S. base in the Middle East. Unverified reports and a video show that the aircraft may have been damaged after being attacked by Iran’s air defense weapons.

Iran’s Islamic Revolutionary Guard Corps then released a video showing the moment the F-35 aircraft was hit over Iran. The footage was captured by a forward-looking infrared system. Outside observers widely believe that Iran indeed hit the F-35, and this is the first time in combat that a fifth-generation stealth fighter has been struck by ground fire. Although it was not shot down, it is a landmark incident, marking that the stealth performance of fifth-generation aircraft is no longer, as in the past, an absolute position of air dominance.

How exactly did Iran do it, and what kind of weapon produced this result?

Personally, I think this was first of all a tactical success. In the opening phase of the war, many Iranian air-defense facilities were destroyed, and the U.S.-led coalition has maintained a long-term, high-frequency pattern of attack activities over Iran. Because equipment such as warning radars that could potentially expose signals, once powered on, is easily targeted by the other side’s air fire, Iran’s ground-based air-defense system was actually very difficult to mount a comprehensive counter.

As the weaker side, Iran could only take measures such as turning on and firing within a short window, and conducting stealthy and mobile maneuvers for its ground air-defense firepower to achieve combat results. Due to a lack of a complete, integrated air situational monitoring system, Iran had to have some understanding of the operating patterns of the U.S. and Israeli coalition inside Iranian airspace—for example, its entry and exit routes, and the daily flight time, speed, and altitude—so that it could position ground air-defense firepower in advance in ambush near the route that the aircraft had to pass.

Based on the publicly released video from Iran, it is clear that the F-35 was locked on by some kind of air-defense weapon based on an electro-optical thermal imaging detector, and then was attacked.

The air-defense loitering munition that likely produced this result is Iran’s “358” air-defense loitering munition. The 358’s warhead weighs only about 10 kilograms. Because it has low explosive power and low speed, it may have been able to score a hit but not be able to shoot the aircraft down.

Technically speaking, 358 is a completely new-concept air-defense weapon tailored specifically for targets such as the F-35 or the MQ-9 Reaper. Its feature is that it does not need to wait for the target to come close before it launches for interception; instead, it loiters in the air and sets up an ambush. This missile does not emit any signals. It only needs to identify and lock the target based on the target’s infrared signature, so the target’s own electronic warfare equipment will not trigger alarms due to radar-wave emissions.

Although the F-35 has a very advanced infrared missile approach warning system specifically designed to detect attacks from such air-defense missiles that do not emit signals, the 358 missile uses a micro turbojet engine with a very low infrared signature. Its inherent flight speed is only 0.6 Mach. This could potentially fool the warning system into thinking it is a slow, small aircraft rather than a major, high-threat air-defense weapon. As long as there is a slight hesitation—before it’s too late to release decoys and accelerate to escape—it could end up being hit.

The F-35 itself does not have supersonic cruise capability, and it is a single-engine fighter; therefore, when it encounters an ambush, it is also relatively easy for it to be shot down. In contrast, the F-22, which is also a fifth-generation aircraft, is a twin-engine fighter with supersonic cruise capability. Because its speed is high, even if it is ambushed, the time window for the 358’s hit would be extremely narrow.

In addition to the purpose-built thermal imaging electro-optical guided missile, Iran has also gradually restored its ability to掌握 air situational awareness in its own airspace through a distributed air-defense network. After the war began, the IRGC clearly understood that its gap with the U.S. military in electronic warfare was too large, and that the risk of turning on radar systems was too high. Therefore, it began to deploy large numbers of infrared electro-optical sensing equipment in mountainous areas across central and western parts of the country. By integrating the air intelligence collected by such low-cost, low-technology detectors through data links, it completed its grasp of the U.S. and Israeli air force’s activity patterns.

Previously, the detection range of electro-optical sensors and the clarity of thermal imaging had always been inferior to radar detection. Ten years ago, the operational coverage for electro-optical detection was only around 50 kilometers, essentially just enough to meet close-in air defense needs. In the past 10 years, technology for infrared thermal imaging chips has improved continuously, and multi-source detection technology has also become increasingly mature, with working distances now reaching the level of 400 kilometers.

In recent years, the technology for measuring range using electro-optical signal ranging has also seen significant improvements. Currently, there are two methods for range measurement with electro-optical equipment. One uses laser radar; its ranging accuracy can reach centimeter-level precision, but once it emits a laser signal, it will also trigger the other side’s alarms, exposing itself. The second method is to calculate the influence on the target’s distance using algorithms—for example, combining the images obtained from multiple sensors to compute distance and position (like when a person closes one eye and loses the sense of distance, but when both eyes are open, the object seen by two eyes is combined to generate a sense of distance). In addition, distance can also be calculated by pixel-point computation of a known target. Based on the principle of nearer appears larger and farther appears smaller, targets at different distances will have different numbers of pixels in the imaging. This is also an important basis for judging distance. Even if only a single sensor detects the target, distance can still be generated using this principle.

When computing power was insufficient in the past, the range-estimation error for these approaches that do not rely on laser ranging was very large. But with improvements in computing power and artificial intelligence technology, the problems of “can’t see clearly” and “can’t compute accurately” for traditional algorithms in complex backgrounds have already been basically resolved. The accuracy of algorithm-based range measurement is now close to about 97% of laser ranging. It has reached a level that can be applied in real combat. This is a technology that did not exist when developing fifth-generation aircraft. As a result, the stealth fighters designed at that time were, in fact, no longer able to cope with the rapid advances in electro-optical technology. This is the inevitable result of technology and defensive means upgrading after prolonged confrontation.

For the side that has stealth fighters, there is already technology to deal with this kind of new air-defense weapon—for example, it was previously reported that the U.S. military tested an F-22 equipped with a “mirror” or “mosaic” coating at the famous “Area 51.” This is believed to be a new type of stealth coating for sixth-generation aircraft. It not only achieves radar stealth, but can even achieve optical stealth by changing the thermal imaging signal characteristics on mosaic pixels, as well as by reflecting aerial images from other directions.

I’ve previously seen a British company demonstrate infrared stealth coating for tanks at a defense exhibition in Europe. It can make a main battle tank appear like a household sedan in infrared thermal imaging, in order to deceive the opponent. Sixth-generation fighters will very likely apply this technology—to make stealth aircraft unclear to optical sensors, or to make them be identified as other objects.

Another effective countermeasure is to use a hard-kill approach: equip laser weapons to burn up the infrared seeker heads of missiles, and equip miniaturized missiles to intercept such low-speed loitering munitions. In addition, it is possible to equip fighters with unmanned loyal wingmen to counter potential threats. These are all technologies that sixth-generation aircraft are currently working on for research and development.

In summary, Iran’s tactical victory this time shows that the stealth technology of the previous generation is no longer invincible. The new-generation stealth technology, as well as targeted anti–air-defense countermeasures, will inevitably accelerate research and development and deployment in the battlefield.