The prospective benefits of extensive drone operations point to an expansion of commercial operations in the urban environment over the coming decade. Operation in this complex environment, as compared to more remote and less densely populated areas, requires a more intense focus on considerations of risk (personal injury and property damage), technological protections and mitigations, management of very low-level airspace and its traffic, as well as aviation regulation, planning law and the rights of individuals to their privacy and peace.

The risks of confliction between drones and manned aircraft, particularly in relation to aerodromes (including major airports), causes considerable concern to the public, regulators, aircraft operators and other stakeholders. Aerodromes and their airspace host a concentration of air traffic, and whilst there have not been any major incidents involving drones and a passenger aircraft resulting in a catastrophic loss of human lives at the date of publication, there have been a number of airport closures, flight delays and near-collisions with commercial aircraft involving drones all around the world.

A number of major airports have closed their runways due to the reported presence of uncooperative and unauthorised drones, resulting in disruption. For example, London Gatwick Airport suspended operations for 36 hours in 2018 due to the presence of one or more drones apparently operated with intent to cause disruption. The cost of this episode to industry and the airport operator has been estimated at £50 million. There have been other incursion events causing suspension of airport operations at Dubai International Airport, Singapore Changi Airport and Frankfurt.

Most recently in Australia the Civil Aviation Safety Authority (CASA) stated in November 2021 that it is working with communities in southeast Queensland and northern NSW to address a spike in the number of drones being flown in restricted airspace around Gold Coast Airport.

Regulation

To date, government regulation in many States around safe and successful integration of drones into airspace has been predominantly reactive, focussing on limitations on or exclusion of flight over geographical areas or in volumes of airspace for the purposes of safety. One pertinent aspect of this concerns the limitations on operation of drones, which commonly include altitude ceilings, limitation of flight to within visual line of sight (or other limited distance) of the drone pilot, and the designation of protected (no-fly) zones around critical facilities and infrastructure, including aerodromes.

The rapid growth in the number and deployment of drones, especially in high density population areas, coupled with the very real risk of collisions with aircraft have prompted more comprehensive responses. Two such responses – Geofencing and Countermeasures - are described below.

Geo-fencing

Geo-fencing is being considered by States as a mechanism to mitigate the risk of drones and can be described as "a virtual barrier which can be used to prevent RPAS from entering restricted airspace". A large proportion of commercially available drones already include geo-fencing capabilities (software and data contained in the drone that can restrict it from flying in certain areas, such as airports). Geo-fencing may be used to contain drones within a particular area, or to exclude drones from sensitive areas, such as in the airspace of airports, to prevent drone interference with other aircraft activity.

Although there is much support for the installation of geo-fencing as a way to mitigate the risk of a drone flying near a controlled airspace, there are still concerns surrounding the cost of implementing such technology as not all manufacturers have this capability. In addition, there are also concerns around the liability and reputational risk for manufacturers where the geo-fencing system is based on a database that is to be developed and published by regulatory authorities. Other questions and issues to be addressed, include: what happens to a drone once it approaches or reaches a geo-fencing area? Does it fall to the ground? Return to its owner? Is it diverted in some other direction or to another location? Will geo-fencing systems also impact other low flying aircraft (that is, piloted aircraft, not drones) in the surrounding area? These questions all involve considerations that are made more challenging by a complex and busy environment, such as urban airspace.

Geo-fencing software can be installed in the drone itself, but the cost implications of mandating the inclusion of the software in all drones could be prohibitive to some manufacturers or users. There is also the consideration of the need to ensure access by drones of varying type and design to real-time/current geo-fencing data; for example, to ensure that temporary exclusion or danger zones are flagged to each drone’s system. The “geofencing landscape” will not necessarily be static in the area of drone operation. In turn the requirements for reliable access to data raise questions concerning how that data (and its means of communication) can be made “universally” accessible; harmonisation of the technology, protocols and data format with the broad spectrum of manufacturers technology poses challenges for many States.

Although advances in technology show promise that geo-fencing will be an integral tool to the management of drones in the future, CASA has stated that at this time, the geo-fencing technology available does not meet the requisite levels of technical reliability. The UK government stated recently that it was working with drone manufacturers and industry to determine how geo-fencing capabilities may be improved and with the Civil Aviation Authority (CAA) to ensure robust data on airspace restrictions, such as those around airports and other critical national sites is available in a format that manufacturers and developers can easily use.

Further development in this area is required before it is coined by regulators as 'technically reliable' but it is expected to fully integrate with UAS traffic management (UTM) systems to enhance the overall safety of drone operations around aerodromes.

Countermeasures

Current countermeasures available to seek to neutralise the risks posed by drones (once detected) to manned aircraft, and in and around aerodromes, are many and varied. They broadly fall under two categories – often grouped as 'kinetic' and 'non-kinetic'.

Kinetic systems cover all measures designed to physically disable or intercept a drone mid-flight. For example, the deployment of weapons utilising high energy laser or microwave technology to interfere with key component parts of the drone, rendering it inoperable.

Most kinetic techniques have, to date, only been employed in a military setting. There are obvious concerns as to their suitability in the airspace around aerodromes, given the high volume of air traffic, and the risk a physically damaged or disabled drone is likely to pose to crowded areas. It is perhaps also to be noted that the effective range of some kinetic techniques is considerably beyond the likely range to the offending drone, raising questions as to what happens if the kinetic agent misses. Hurdles also exist in terms of the legality of some of these measures under local laws.

Non-kinetic, or electronic, countermeasures apply radio frequency or GPS jamming technology to disrupt the link between the drone and the drone pilot / controller. A related technique involves manipulating the drone's command system to effectively take over control of the drone from the actual pilot. In each case, the intention is to override the operations of the drone that have raised the safety risk and allow the drone to be brought to a controlled landing or return to its initial or 'home' location.

A consistent and widely adopted approach to drone countermeasures for aerodromes is not yet established. Nevertheless, the risks are well known, and governments and key stakeholders are increasingly taking proactive steps to put in place protective measures to avoid the type of scenario seen at some major international airports in recent years. There are numerous programmes in various States that are working towards standards and specifications for counter-measures systems that can then be more broadly approved for use around major infrastructure, including aerodromes under existing legislation.

Following the drone disruption event at London Gatwick Airport in late 2018, operators of a number of the UK's major aerodromes worked quickly with government authorities to source and invest in drone tracking, detection and deterrent systems. While operators are understandably reluctant to disclose specific details of the systems currently employed, it is understood they include a combination of kinetic and non-kinetic countermeasures. Collaboration between national aviation authorities and airports on drone detection is also becoming more common place. For example, in Australia, it was announced in late 2019 that the Civil Aviation Safety Authority had partnered with Airservices Australia (Australia's chief provider of air traffic control services) on a program to detect and track drone activity at Australian airports. The program is said to run at 29 of Australia's busiest airports.

Comments

The infrastructure and services to support the integration of drones into shared airspace is being actively developed at this time and with the aim of reducing those risks. Research continues apace and that will undoubtedly refine the understanding of the risks posed and how to mitigate and protect against them.

The primary responsibility for safe operation of the drone lies with the pilot and the operator, but it is perhaps not too difficult to foresee that they may increasingly depend upon technological safeguards "built-in" to the drone (See, for example, EASA Special Condition Light Unmanned Aircraft Systems – Medium Risk 17 December 2020). Regulators presently contemplate that measures to mitigate the risk of incursion of a drone in to (say) aerodrome airspace or above a certain altitude, may be effected through aspects of the drone design. For example, Commission Delegated Regulation (EU) 2019/945, article 6(1), requires altitude limits (or limiters) and "geo-awareness" functionalities by design in certain classes of small drones to be placed on the mass market; and contemplates (although it does not require) functions limiting a drone’s access to certain volumes of airspace.

Regulators globally do envisage that technology such as "geo-fencing" software, electronic conspicuity and other built-in safety features will be mandated in design standards that all manufacturers may be required to include in their drones. Much of this safety technology is already available on certain mass-marketed drones and will evolve in the next few years.

The European Commission has referred to the balance between the obligations of drones manufacturers and operators in relation to safety and the Federal Aviation Administration ("FAA") has already imposed safety obligations on manufacturers who will be required to self-certify that their products comply with the relevant safety standards (See Federal Aviation Authority Reauthorization Act of 2018, s.345). It appears inevitable that the evolution of the safety responsibilities of the manufacturer will increasingly expose them to liability and other sanctions for non-compliance.

The exponential growth in the use and deployment of drones globally and of the technology underpinning their scope and operation dictates that international and national regulations and associated security and commercial arrangements such as insurance will continue to evolve.