Unmanned Aircraft Systems (UAS), their market and their operations, are the future for airborne mobility and logistics and will have a significant impact on aviation. To facilitate safe access to airspace for the increasing numbers of unmanned aircraft (UA), a dedicated UAS traffic management (UTM) system has been proposed and is currently being developed.
The purpose of a UTM is to safely manage UAS operations both in controlled and uncontrolled airspace using a high degree of automation. Information will automatically be collected from and distributed to all affected stakeholders leaving the UAS operator to be responsible for managing its operations safely without direct interaction with Air Traffic Management (ATM).
In the short to medium term, the development of UTM will focus on Very Low-Level Airspace (typically 500ft and below) to accommodate Urban Air Mobility (UAM), parcel delivery, industrial applications, etc. Even though UTM is still a general concept with no altitude restrictions, this initial development is focused on low-level airspace with the potential to leverage off knowledge gained to apply to Very High-Level Operations like stratospheric balloons or hypersonic vehicles into the future (ETM: Upper-E Traffic Management).
Due to different technologies and capabilities, specific operational requirements and limitations, and different regulatory requirements, UTM is considered a separate, but potentially complementary, system to the ANSP-supplied ATM. In fact, all the fundamental characteristics of an ATM system (Air Traffic Services, Air Space Management, Air Traffic Flow Management TFM) can also be found, with the necessary peculiarities, in UTM.
It is anticipated that in the future the two systems will converge into one traffic management system providing a seamless service to all airspace users with manned airspace users maintaining existing operational capacity and safety standards.
In order to promote safe, efficient and consistent regulation, and to assist and advise in the development of safe and orderly systems of Air Traffic Control, IFATCA would like to provide the following observations with a view to contributing to ongoing development of UTM.
The aviation sector is highly regulated both nationally and internationally and this contributes to the industry’s outstanding safety record. Given the stakeholders that will share the airspace, effective regulation is essential to safeguard airspace users: starting points should be airspace classification and flight rules. Furthermore, a basic and common reference is necessary to set standards and to transmit information amongst all systems.
A fundamental assumption of existing aviation regulation is the presence of a pilot on board the aircraft. Obviously UAS lack on-board pilots. However advancements in technology can compensate for this to a degree. Airspace classification and flight rules result in specific procedures applied by Air Traffic Controllers and pilots to ensure separation minima is maintained and aircraft are safely operated.
However, without on-board pilots, legacy procedures and resulting separation minima are difficult, if not impossible, to maintain. In particular, separation requiring a human element (e.g. see and avoid) may not be available unless it can be supplemented or replaced by a technical solution.
A fundamental pillar of any UTM system must be a regulatory framework that permits the clear and safe application of the procedures.
UTM is expected to be a digital and web-based environment based on a high level of automation. However, most of the current UTM architectures still require direct intervention from Air Traffic Control for the authorization of UAS missions (approval of the flight path, approval of take-off and landing) especially if these are conducted into controlled airspace or near controlled airport. To do this, ATC still has to be provided with the required information. This will requires a clear delineation of responsibilities with appropriate legal and operative frameworks.
All UAS operations in non-segregated airspace must be in full compliance with ICAO and/or national and/or local regulations.
ATCOs shall not be held liable for incidents or accidents resulting from the operations of UAS that are not in compliance with ICAO and/or national and/or local regulations, in non-segregated airspace.
Standardized procedures, training and guidance material shall be provided before integrating UAS into the Civil Aviation System.
Establishing a clear and robust ruleset is essential to an effective delineation between ATM and UTM, “ATM-UTM boundary” as defined by ICAO. This boundary, and associated procedures, requires a clear understanding of the roles and responsibilities of the stakeholders involved. Without full integration, this element is essential.
The UTM-ATM boundary shall allow an unambiguous identification of responsibilities and functions of the two systems.
In the case of a conflict between two or more UA, unmanned operators will contribute in solving the conflict using the UTM system capabilities to ensure the safety of the operations. In the case of a conflict between manned (ATM) and unmanned aircraft (UTM), a shared and common situational awareness is fundamental to ensuring coordinated action is taken and separation occurs.
Introductions of new Mixed Mode Operations should be avoided by creating intrinsically safe solutions.
When safety of a Mixed Mode Operation cannot be completely managed at an intrinsic level, assessment must take place that the change in the ATM system does not increase controller workload to an unacceptable level.
Highly digitalised and web-based solutions pose a great challenge in appointing responsibilities and liabilities when events occur.
Automation must assist and support ATCOs in the execution of their duties.
The legal aspects of a controller’s responsibilities must be clearly identified when working with automated systems.
A Controller shall not be held liable for incidents that may occur due to the use of inaccurate data if he is unable to check the integrity of the information received.
A Controller shall not be held liable for incidents in which a loss of separation occurs due to a resolution advisory issued by an automated system.
 IFATCA defines mixed mode operations as ATM Operations that require different procedures due to variances in airspace users’ characteristics and/or ATM design within the same area of controller responsibility.
Interface between UTM and ATM is critically important. The interface is the means through which information is exchanged. It ensures a correct global situational awareness so all stakeholders are provided with the necessary information to take appropriate actions for deconfliction and separation management.
The interface between the systems shall guarantee the exchange of the necessary information for the safe management of the traffic.
Without a clear operational framework to manage UA and manned aircraft together, it’s challenging to identify the information that needs to be provided by and exchanged amongst stakeholders. Changes to the ATM must be an improvement and no compromises for the safety levels of the current system are accepted.
Total workload should not be increased without proof that the combined automated/human systems can operate safely at the levels of workload predicted, and to be able to satisfactorily manage normal and abnormal occurrences.
The integration of UA and manned aviation should improve the use and the efficiency of the airspace while reducing the overall complexity of the operations. IFATCA recommends a phased approach that proceeds from segregation ( UAS operations only in dedicated and segregated areas) to accommodation (condition when an UAS can operate with some level of adaptation or support that compensates for its inability to comply within existing operational constructs) to ultimately full integration. The deployment of the UTM should proceed in accordance.
A phased approach (segregation, accommodation, integration) should be adopted to allow unmanned operations inside the airspace. Comprehensive regulatory framework and procedures for the ATM-UTM interaction shall be established before the implementation of each phase.
Furthermore, IFATCA recommends operational controllers are involved in the design, development and implementation of the new system.
Operational controllers shall be involved in the design, development and implementation of new ATM systems.
Safety aspects are paramount and the (relatively) new type of operations could have safety impacts that haven’t been evaluated nor discovered yet. The tension between safety and commercial imperatives will have to be managed.
The introduction of UTM shall not reduce the safety of the ATM system.
Two or more providers operating in the same airspace offering the same services is new in traffic management. Competition may result in numerous platforms for the UTM and without international standards may create difficulties exchanging information amongst UTM users and with ATM.
IFATCA recommends that all parties involved in airport and airspace design address intrinsic safety with the highest priority.
Any changes to aviation should be managed holistically as part of a Safety Management System (SMS). This approach is endorsed by ICAO (Annex 19) and legislated by the Single European Sky Performance Scheme. An essential component of an SMS is the risk assessment; that is, analysing any change to an existing system for the potential to increase risk and hazard. There is no shortage of tools and techniques to assess risk.
IFATCA recommends the development of risk-based procedures for UAS operations.
It is important that a UTM is coordinated and developed with the ultimate goal on integration to the current ATM system. This requires discussion, standardisation and a UTM safety risk assessment model.
The fundamental aspect remains the adoption of an adequate regulatory framework that allows safe interactions between ATM and UTM. The required level of automation shall be carefully evaluated for a clear and unambiguous allocation of responsibilities.
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