Study and Recommendations regarding Unmanned Aircraft System Geo-Limitations

The growth in numbers of small unmanned aircraft systems (UAS), or “drones”, is matched by the significant range of benefits that their use promises. Those benefits will not be fully realised, however, unless there can be confidence that such UAS can be operated safely.

Reports of increasing numbers of safety incidents have understandably given rise to concern not just among the manned aviation community but amongst pioneering UAS manufacturers and operators and the wider public.

Responding to a call from the EASA Executive Director, representatives of the National Aviation Authorities of Finland, France and United Kingdom joined with EASA specialists to form a Task Force to examine thoroughly the risk to manned aircraft from the operation of UAS (mainly in the “Open” category, as defined in Ref. 7) and to consider how best to manage the risk. The Task Force assessed the current understanding of the risk, collated the actions of manufacturers, users and authorities to manage the risk, identified emerging best practice and looked at future options.

The Task Force focused its attention on the means to prevent a conflict with the potential consequence of a collision between a small unmanned aircraft and a large commercial aeroplane operating into a major aerodrome. The Task Force recognised that this constitutes a primary threat to aviation safety and lends itself to mitigation through “geo-limitations” and associated technology. Whilst there are opportunities in product design, operating practices and regulation to manage that risk, too little is known about the likelihood and consequences of such a collision to optimise those opportunities. Thus, further work, including research activities, is needed on understanding that risk.

Since the beginning of its work, the Task Force identified the need to establish globally agreed terminology that includes “geo-limitation” and related terms (e.g. “geo-fencing”), as well as the need to develop the associated concepts, the main of which the Task Force believes to have captured in this report. The definitions of the key concepts used in this report are included in Appendix C (sec. C.2. Definitions)

In forming its views, The Task Force analysed available information and then gathered data and advice by consulting a wide range of stakeholders involved in UAS manufacture, operation and regulation around the World. That consultation was performed in two ways: a survey questionnaire addressing a wide variety of stakeholders, and meetings with some stakeholders (in particular with a number of industry representatives). Appendixes contain both the questionnaire that was circulated and the description of stakeholders' engagement.

Having analysed this information, the Task Force presented a range of conclusions and recommendations. Among the main Task Force conclusions are:

  • Geo-limitation solutions cannot be expected prevent malevolent behaviour, a rationale that applies to many of the Task Force recommendations. Thus, the Task Force focused on the prevention of the unintentional breach of limits.
  • The Task Force noted that EASA’s work to define rules at EU level for UAS operations had yet to conclude and would, in fact, take note of this report. The current lack of information on a number of aspects prevents the production of the required impact assessments. In this context, the Task Force assessed the foreseeable geo-limitation solutions, their benefits and limitations, what would be needed to make them possible and what further work was needed to accelerate implementation of those solutions. 
  • With regard to geo-limitations and their implementation, the Task Force identified as main elements:
    • Provision to UAS operators of up to date, accurate and easily understandable information that helps them to determine restrictions or requirements in effect at the location where they want to operate. This information could be more easily provided to UAS operators by integrating it into the remote pilot station or make it accessible through a standalone mobile application.
    • UAS performance limitations, including height or altitude limitation and range (horizontal distance to the remote pilot station or to the take-off point) limitation. The Task Force favoured height limitation as the main performance limitation that can effectively contribute to mitigate the risk of collision not only in the vicinity of aerodromes. 
    • Requirement for UAS designs to include built-in features that warn the remote pilot when the unmanned aircraft is starting up in, or approaching to, a zone subject to UAS restrictions.
    • Requirement for UAS to incorporate geo-fencing, which requires position-sensing and control functions, sufficient to comply with any restrictions on where and when a UAS might operate. 
  • The Task Force concluded that, when establishing geo-limitations of sensitive zones, Member States use the concept of Prohibited and Restricted zones, as defined in the rules of the air. 
  • To respect these geo-limitations through the use of automatic functions (i.e. geo-fencing, performance limitation functions) and, at the same time, allow the removal of such limitations for authorised operators, the Task Force identified the need to define “hardlocked” and “soft-locked” geo-limitations and the corresponding un-locking processes. 
  • When regulating the use of such automatic functions the Task Force noted the need to keep rules technology-neutral and to provide the UAS manufacturing industry with appropriate scope to generate solutions and to propose any necessary technology standards. Besides, product requirements and standards must be applicable to UAS operating in Europe, and not just those produced by European manufacturers.
  • When mandating automatic geo-limitation functions, the Task Force concluded that the mandate should apply to all products for operation in a given sub-category within the Open category, those sub-categories being established so as not to exclude the majority of UAS sold for recreational use. Mechanisms to grant exemptions in order to cope with specific needs and situations might be necessary. 
  • With regard to mandating a retrofit of these automatic functions to the existing UAS fleet, the Task Force concluded that, considering the relatively short average lifetime of UAS products and difficulties (or impossibility) of implementation, retrofitting should not be mandated and, instead, further operational limitations should be considered where appropriate.
  • Regarding model aircraft, the Task Force concluded that current rights for their operation granted by Member States should be grandfathered. As Member States are best placed to deal with this particular segment of Unmanned Aviation, no “geo-limitation” functions should be required for that segment at European regulations level. Besides, in most cases, the technology involved in model aircraft would not make it feasible to implement automatic geo-limitation functions. 
  • For homebuilt UAS, the Task Force concluded that requirements similar to those for consumer-retailed UAS should apply in terms of, at least, pilot competencies, registration and electronic identification. Similarly, the COTS guidance navigation control components of homebuilt UAS should be subject to the product requirements applicable to UAS that are subject to geo-limitation function requirements.
  • Regarding industry standards, the Task Force identified a number of “geo-limitation” related aspects as candidates. The Task Force identified EUROCAE as the organisation best suited to lead the European effort to develop standards working in coordination with ESOs and other industry standard bodies. Any standards must be a good fit to the characteristics of the small UAS business and be able to achieve tangible results that can be implemented by the small UAS industry in the short timeframe that this particular business segment requires.

These conclusions led the Task Force to formulate a number of recommendations, which have been presented throughout the report and put together in section 7.2.

Finally, it must be noted that this Report is just an initial step to address “Geo-limitation” aspects for UAS. The content of the Report, and its recommendations in particular, indicate follow on activities that are needed. The Task Force sees JARUS as the right forum to drive these activities forward on the regulatory side. This is because JARUS has gathered together a significant number of national aviation authorities and other relevant organisations, has been working for some years on regulatory material for Light UAS, and now includes representatives of stakeholders directly involved in the segment of small UAS and in the operations that are more likely to be affected by “geo-limitations”.