Elevated risk of jihadist groups in Western Europe utilising commercial UAVs, particularly against airports

There was no evidence of malicious intent in this incident and the HMS Queen Elizabeth was not deployed tactically; it is not due to become operational until 2021. The incident nevertheless highlights how unmanned aerial vehicles (UAVs) can be used by civilian operators to penetrate secure sites or other restricted areas where they constitute a potential hazard.

Regulations governing the use of commercially available UAVs vary considerably across the EU member states. The European Union is aiming to establish a coherent and comprehensive regulatory framework to mitigate the security threats associated with their proliferation. The EU regulatory proposals, due in late 2017, will include requirements for UAVs to be remotely identifiable and for individuals operating UAVs weighing more than 250 grams to register their vehicles. Geo-fencing technology, which prevents UAVs from entering prohibited zones such as airports, nuclear sites, city centres, and areas where there are large congregations of people, is also likely to become compulsory on all UAVs. These regulations are, however, unlikely to be introduced before 2019 and are unlikely to be fully effective in countering terrorist use of UAVs.

UAV weaponisation

A Mining and Geological Searches Bureau (Bureau de Recherches Géologiques et Minières: BRGM) researcher uses a drone to map the coastline on Petit Nice beach on 1 March 2017.

Thibaud Moritz/AFP/Getty Images: 646750116

UAVs have predominantly been used by militant groups in Iraq and Syria in an aerial reconnaissance and target acquisition role. The Islamic State is, however, also developing its UAV-borne improvised explosive device (IED) capability. The use of UAVs has also featured heavily in Islamic State propaganda videos, with the probable aim of providing inspiration to other actors beyond Syrian and Iraqi borders. IHS Markit notes that while the group's English-language magazines Rumiyah and Dabiq have not yet explicitly encouraged the use of UAVs as a potential mode of attack, this is becoming more likely.

Access to highly explosive materials remains a limiting factor restricting the European militants' ability to weaponise UAVs. The Islamic State has developed the capability to drop IEDs from quadcopter and fixed-wing UAVs in Syria, but even there the effectiveness of these improvised weapons is limited by their relatively small payload and radio frequency jamming countermeasures. A video released on 24 January 2017 indicates that the Islamic State has now developed a mechanism for dropping IEDs assembled using 40-mm grenades (normally fired from under-barrel (low velocity 40x46 mm) and automatic (high velocity 40x53 mm) grenade launchers) with improvised stabilisation mechanisms from UAVs that can return to their launch points and be reused, thereby reducing the cost of carrying out such attacks. Growing and improving use of weaponised hobbyist UAVs by the Islamic State in Iraq and Syria increases the likelihood of jihadist sympathisers experimenting with this technology in other theatres, with Europe at the highest risk.

Aviation-specific vulnerabilities

The aviation sector has long been an important aspirational target for Islamist militant groups due in part to the publicity gained by such high-impact attacks, but also to the potential economic and reputational damage that a successful attack would generate. The Islamic State's propaganda has on several occasions highlighted the benefits of attacking airports and aircraft, and the group has successfully targeted both Zaventem airport in Brussels and Ataturk airport in Istanbul in March and June 2016, respectively.

UAVs present an attractive option for militants looking to target the aviation sector in the West. Most UAV manufacturers already include ring-fencing of airports and other sensitive facilities in their software, which prevents them from flying over such areas. The technology can, however, be hacked by individuals with the required skillsets. An explosive-rigged UAV could potentially also be used to breach airport security and target stationary aircraft or airport facilities. Such an attack, even if unsuccessful, would damage public perception of flight safety and likely cause severe disruption to the industry, disproportionate to the level of physical damage incurred. Small/medium-sized domestic airports are at a higher risk than large international airports, which are more likely to be protected by UAV counter-measures.

Provided non-state armed groups (NSAGs) succeed in circumventing manufacturer fail-safes designed to prevent them from flying over airport grounds, they could also attempt to fly UAVs into the engines of a flight during take-off and landing, potentially damaging the aircraft and downing it. Even without malicious intent, the increase in the number of incidents in which aircraft have come close to colliding with UAVs indicates a growing threat to aviation. Highlighting this vulnerability, according to the UK Airprox Board, there were 70 reports of UAVs coming dangerously close to aircraft in the UK in 2016, more than double the number in 2015. A further 33 incidents were reported in the first five months of 2017.

Risks to individuals

The Islamic State in Syria and Iraq frequently targets small groups of people and individual vehicles with great accuracy by using quadcopter UAVs. This tactic could be extended to Islamic State supporters or other NSAGs in Europe. Public events like concerts, sporting events or demonstrations, or other open-space gatherings attended by high-profile figures could be attacked from the air, causing indiscriminate civilian casualties.

UAVs also have the potential to be used to disperse chemical or biological agents over a crowded area. Although chemical, biological, radiological, and nuclear materials would be extremely difficult to obtain, relatively available hazardous materials like battery acid, bleach, or hydrochloric acid could be used in symbolic attacks intended to damage public confidence rather than incur mass casualties. There are commercially available crop-dusting UAVs that can carry several litres of chemicals, although these are subject to much more extensive regulations than hobbyist grade UAVs. Should insurgent factions opt for chemical attacks using UAVs, they would probably be limited to using modified hobbyist drones like the DJI Phantom, which can carry payloads of up to 2–3kg.

Outlook and implications

Any of the aforementioned attack methods would require UAV customisation, as well as either the fabrication of explosives or the procurement of noxious substances. They would, therefore, require a considerable amount of expertise, organisation, and for certain aspects, knowledge transfer from operatives. These factors significantly increase the risk of detection by security services in Europe, somewhat mitigating the threat. We assess the risk of European-based militants weaponising UAVs and using them to attack publicly accessible spaces to be elevated; a successful attack on secure airports is much less likely, with small domestic airports at a higher risk than international airports, which are more likely to have UAV counter-measures in place.

Either a successful or failed attack involving a UAV would have major ramifications for multiple sectors, including aviation, tourism, wholesale retail and trade, and entertainment venues. Governments and military have already developed a range of UAV countermeasures, with the vast majority of such devices employing electronic means such as jamming or laser systems to disable the vehicle. It is unclear from open sources how these systems are deployed in a civilian context, with much of the information surrounding UAV defence measures not publicly disclosed. The lack of public knowledge of these countermeasures would magnify the detrimental effect on public perceptions of safety and security in the event of a successful attack.