Fears of 'kill switch' in US weapons stir global debate
Occasionally, the topic of "source codes" resurfaces like a boomerang. These are codes that manufacturers are said to install in various weapons systems, and the countries that own them use them as leverage over buyers.
The topic recently reemerged under a new name: the kill switch. This was related to the evolving political situation; the new US administration began threatening countries like Canada, Mexico, and the European Union with sanctions and temporarily cut off Ukraine from military aid.
As a result, experts in many countries started to question the wisdom of purchasing American weapons. Should alternatives be sought if the US is not a 100-percent reliable partner? For example, criticism resurfaced in Germany regarding the purchase of F-35 fighter jets (Germany bought 35 aircraft in 2022 for $8.3 billion). Meanwhile, in Poland, a discussion initiated by former Deputy Prime Minister and Minister of National Defense Mariusz Błaszczak questioned whether the Americans might "turn off" their HIMARS systems. This discourse is closely tied to the so-called source codes for weapons.
What are source codes?
The famous "source codes" are essentially the textual record of software content. Computers, such as mission systems or fire control systems, develop output code based on this, creating a set of available commands. This concept also applies to smartphones, washing machines, and modern cars. In weapons systems, managing these codes is crucial for both the manufacturer and the user.
Source code records contain information needed for tasks like arming F-16 or F-35 jets with bombs and missiles of American production. However, if counterparts were designed in Poland, obtaining the aircraft manufacturer's permission would be necessary to equip them with domestic weapon systems, unless significant efforts, like those made by the Turks, were employed to bypass such restrictions. The situation is similar for aircraft (and more) produced by French, Italian, European, and other manufacturers. The source code does not provide a means to disable a system a non-compliant user uses. Are there different options?
"Disable" the F-35
A debate has emerged in Germany about whether purchasing F-35s (and American weapons in general) is safe and whether Washington might disable them if it views Germany or the European Union as a competitor. Official confirmation of this concern has not been found.
Lt. Col. Łukasz Treder from the F-35 Program Implementation Team for the Polish Armed Forces commented that one should ask whether the administrator of a complex IT system could embed conditional instructions in a low-level programming language that might be activated later within the aircraft's software operation.
While somewhat enigmatic, this response highlights the core of the problem: without confirmation, such as grounding the fleet of an F-35 user (or other systems like Rafales, HIMARS, Patriots, or IRIS), certainty about these concerns remains elusive.
In civilian markets, similar practices are more openly discussed. For example, in 2023, a scandal involved Newag, a company that remotely disabled trains it produced if serviced by another company. Similar occurrences happen in the automotive market. There are also unverified reports of American SM-2 anti-aircraft missiles "accidentally" bypassing an MQ-9 Reaper drone mistakenly fired upon by Germany.
On the other hand, officials from Belgium and Switzerland officially deny the existence of a physical "switch." The airplane manufacturer Lockheed Martin also denied these reports. So, the current understanding is that we do not know for sure, but if the manufacturer finds it appropriate to introduce restrictions, they might do so without literally turning off an aircraft or missile.
How to hit without GPS?
One potential method for limiting system functionality is cutting off access to the GPS signal. Only a few satellite navigation systems exist, with the American GPS being the most popular. The GPS is used for navigation and to guide precision weapons.
However, Lt. Col. Treder notes that the primary form of navigation is interference-resistant inertial navigation, which measures accelerations and angular velocities to determine an object's orientation and position. He added that GPS narrows our measurement error, but jamming its signal or spoofing attacks could affect the precision of strikes. This is why anti-jamming receivers, like those from Collins Aerospace on the F-35, are installed on aircraft.
Various companies are developing accurate navigation systems that bypass GPS. Additionally, Lt. Col. Treder assures us that "pilots can return home safely without GPS." The challenge lies in missile guidance, which could become as ineffective in combat as unguided missiles without GPS, though they would still be much more expensive.
Other options
Manufacturers do maintain some control over their products. Regarding the F-35, according to the program support team, foreign operators are not allowed to conduct independent test operations outside the continental US under US policy. US government security policies require that US citizens perform specific functions to protect critical technologies. This reflects strict US control over advanced solutions used in the F-35 (the only exception being Israel, which can operate its F-35I independently). However, this is not a "switch" but a "safety valve" for integrating the F-35 with non-approved systems.
Another possibility involves the mission data file (MDF) archive, which enables key functions like determining flight paths with limited detectability, managing communications, and some mission aspects. Without MDF updates, the combat effectiveness of the F-35 would quickly diminish.
The real leverage is much more straightforward than the alleged ability to disconnect part of the F-35 fleet (or another weapons system) with a "red button." In essence, cutting off the fleet from service support is sufficient.
Modern combat systems are highly complex. Each tank, self-propelled gun, drone, ship, or aircraft consists of intricate, often electronically controlled components with specific durability. The manufacturer usually significantly (though not entirely) controls aspects of system operation management. In the US, some elements must be serviced exclusively at designated facilities, and service knowledge is kept within their bounds.
Disconnecting the user of an imported weapons system from service support would severely limit the operational efficiency of the machine fleet within a few months at most. Of course, cannibalization or sourcing spare parts through underground methods might prolong the fleet's lifespan (as with Iranian F-14s), but it would only delay the inevitable.
Thus, neither the Americans, the French, the Germans, nor other leading arms manufacturers need to resort to installing "emergency plugs" in their most advanced systems.
