The Swedish BK M90 is an air-launched cluster munition dispenser developed in the 1990s by Saab Bofors Dynamics for the Swedish Air Force. It is designed to be used from aircraft, primarily the Saab JAS 39 Gripen and older Saab 37 Viggen, to deliver a range of submunitions, including anti-personnel and anti-tank bomblets. It is known as a stand-off weapon, meaning it allows the aircraft to release the dispenser at a safe distance from the target, reducing the risk of exposure to enemy defenses.
(AJS37 with 4 BK-90 pods)
Key Points in the Development of the BK M90:
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Background and Design: The BK M90 was developed as part of Sweden’s efforts to modernize its military capabilities in the post-Cold War era. The weapon is based on the German DWS-24, a cluster munition system, built by DaimlerCrysler aerospace. It was intended to provide the Swedish Air Force with a highly effective way to target both troops and armored vehicles over a wide area.The BK M90 is a glide bomb, meaning it does not have its own propulsion system, but it can glide towards its target after release. It is designed with a precision navigation system that uses inertial guidance, which allows for accurate targeting even in adverse weather conditions.
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Submunitions: The BK M90 can carry two different types of submunitions, a total of 72 munitions, including:
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MJ1: Armor-penetrating bomblets, designed to target vehicles and armored personnel carriers.
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MJ2: Anti-personnel submunitions, which are designed to cover a large area to maximize their effectiveness against enemy infantry.
These submunitions are dispersed over a wide area as the dispenser glides over the target zone, creating multiple points of impact that increase the likelihood of hitting both personnel and vehicles.
(Operation of dispensary)
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Operational Role: The BK M90 was developed for use in scenarios where the Swedish Air Force needed to quickly disable or destroy enemy ground forces, particularly in situations where there might be a mixture of personnel and light to medium armored vehicles. The ability to release the weapon from a distance (stand-off capability) enhances the survivability of the aircraft and its crew in contested environments.
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Service History: The BK M90 entered service in the 1990s and has been integrated into the arsenal of the Swedish Air Force. It has not been widely exported or used in combat to date, but it remains a key component of Sweden’s air-to-ground capability, particularly for defensive operations. Sweden’s defense strategy, which has historically emphasized self-reliance and preparedness for defending its territory, made the BK-90 an important part of its air force’s tools for deterring invasions or large-scale ground attacks.
(Gripen Sporting two BK M90 pods on the inmost pylons, supposedly the only two set to carry them)
- Controversies and International Law: Like many cluster munitions, the BK M90 has faced scrutiny due to concerns over the long-term dangers posed by unexploded bomblets left on the battlefield. Unexploded submunitions can remain hazardous for years, posing risks to civilians after a conflict has ended. As a result, many countries have signed the Convention on Cluster Munitions, a 2008 international treaty that prohibits the use, production, and stockpiling of cluster bombs. Sweden signed the treaty in 2008, which has influenced the role and potential future of the BK M90, particularly with regards to its use in international operations.
Another included system on the submunitions were the “Cluster bombs” are notorious for leaving active un-exploded ordnance (UXO) which failed to detonate upon impact, and for that reason all weapons using sub-munitions for a long time were rejected by the Försvarets Materielverk Defence Materiel Administration deeming it an unacceptable risk.
A very technologically advanced system in the cluster munitions themselves, a system which assigned each individual munition a launch designation code; and under the case the munition was not to explode or not be “cleared for launch” (I.e: the Code isn’t active) would stop the munition from entering “kill mode” and keep unintentional targets safe. While this is mildly classified, it is a segment in the “ELECTRONIC” segment in the FMV manual, which goes over all the electric systems in the BK M90’s housing.
Overall, the BK M90 was a very well planned and thought out design that reflects Sweden’s strategic needs during the 1990s, mainly that of maintaining the iron curtain, able to deploy across the Swe-Fin border in a matter of hours. Despite the UN’s CCM, it contributed as an important keystone in Swedish weapons tech history.
(BK M90 on a loading trolley)
1. Technical Specifications:
- Weight: Approximately 600 kg (1,320 lbs)
- Length: 2.5 meters (8.2 feet)
- Range: The BK-90 is a glide bomb, meaning it has no propulsion system of its own. Its effective range depends on the release altitude and speed of the launching aircraft, with an estimated range of 5-10 km when released at medium altitude.
- Submunitions: The BK M90 can carry either a mix of armor-piercing and anti-personnel submunitions or a purely anti-personnel configuration. Each dispenser typically carries:
- MJ1 Bomblets: Armor-piercing submunitions (used to target light to medium armored vehicles).
- MJ2 Bomblets: Anti-personnel bomblets (designed to cover a wide area).
- Bomblet Capacity: The BK M90 typically carries between 72 to 144 submunitions, depending on the type and loadout.
(The MJ1 & MJ2 submunition type)
2. Guidance System:
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The BK M90 uses inertial guidance with possible GPS updates for precision. This ensures that the weapon can be deployed accurately even in adverse weather or poor visibility.
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CEP (Circular Error Probable): Though exact figures are not always available, it is likely that the BK M90’s CEP (which measures accuracy) would be in the range of 30-50 meters. This makes it relatively precise for a cluster munition but not as accurate as modern guided bombs or missiles.
(This graphic shows the intertial guidance system, and how it would function)
3. Operational Statistics:
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Deployment Platforms: The BK M90 is compatible with the Saab JAS 39 Gripen and Saab AJS37 Viggen aircraft. The Gripen is the would-be primary platform for the BK M90 today, with over 150 Gripens in service with the Swedish Air Force.
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Flight Altitude: The BK M90 can be launched from low to medium altitudes, typically in the range of 100 to 10,000 meters (330 to 33,000 feet), depending on the tactical situation.
(The schematic of the construction and moving parts of the BK M90)
4. Sweden’s Defense Budget and Air Force:
During the period of the BK M90’s development in the late 1980s and early 1990s, Sweden maintained a defense budget of approximately 2-2.5% of its GDP, translating to around $4-5 billion USD annually. The Swedish Air Force focused on maintaining an independent and technologically advanced air defense system, with substantial investments in indigenous platforms like the Gripen and advanced weapons systems such as the BK M90.
5. Cluster Munitions and Humanitarian Impact:
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Failure Rate of Submunitions: Like many cluster munitions, the BK M90’s submunitions have a small but significant dud rate. This means that some bomblets may fail to detonate upon impact, potentially becoming hazardous unexploded ordnance (UXO). The average failure rate for similar systems is around 2-10%, though this can vary based on environmental conditions, altitude of deployment, and the condition of the munitions themselves.
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Estimated Impact Radius: The BK M90 disperses its submunitions over an area typically measuring 200 to 400 meters in diameter, depending on the altitude and speed of deployment. This wide dispersal increases the likelihood of hitting multiple targets but also increases the risk of collateral damage, which has been a significant factor in international discussions about cluster munitions.
(This graphic shows the rectangular cluster release mode, and the glide path of a single unit, multiple could be used in tandem to create a “alley” of mines)
6. Sweden and the Convention on Cluster Munitions:
Sweden signed the Convention on Cluster Munitions in 2008, joining the global effort to eliminate the use and production of these weapons due to their long-term humanitarian risks. However, before signing the treaty, Sweden maintained a significant stockpile of cluster munitions, including the BK M90. The convention required the destruction of stockpiled munitions, though the extent of Sweden’s compliance in terms of specific numbers has not been widely disclosed.
- Global Context: At the time the convention was signed, more than 110 countries had stockpiles of cluster munitions, with global estimates indicating over 1 billion submunitions in existence. The humanitarian cost associated with unexploded cluster bombs has been stark, with 13,306 cluster munitions-related casualties recorded globally between 1999 and 2016.
These figures provide a broader understanding of the BK M90’s technical background, its operational context within the Swedish defense structure, and the wider issues surrounding its use and international regulation.
(BK M90 mounted to a Gripen, seems to be shown in a museum or private hangar)
Taa-daa!
THE FMV BK M90 manual (Declass)
This manual goes over the guidance, electrical, radar, release, data analysis, components, and use case situations. There is much more in depth parts that some Swedish speaking forum members could read and explain for others who would like to know more.
- Yes
- Yes, but in Air RB & Air Sim only
- No
This is also a Video I found on that shows it being tested and mounted on a Gripen in its “aerodynamic testing” phase to make sure it was safe for aircraft use.