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2019-09-12

‘Flight Plan 2030’ Envisions ATC Systems for eVTOLs

Leading aircraft manufacturers and technology providers are laying the groundwork for a practical urban air transportation system by investing in the latest innovations, signalling an imminent urban mobility revolution. Embraer X, Embraer’s innovation division, with Atech, and Harris Corporation has recently released ‘Flight Plan 2030’ — a document defining the crucial factors required in the design and implementation of an “urban air traffic management” (UATM) system. The white paper presents the preliminary concept for the management of low-altitude urban airspace that will allow urban air mobility (UAM) to evolve over the next decade.

Numerous eVTOL (Electric Vertical TakeOff and Landing) models are taking to the skies for testing, while architects and engineers are busy designing future skyports and new technologies that will power future flights. ‘Flight Plan 2030’ draws upon existing air traffic control technology provided by Atech and Harris Corporation and envisions a single urban air traffic control that would not only manage eVTOLs but any aircraft, manned or unmanned. It ideally would create a unified urban air traffic control system that can meet the demands of next-generation air transportation. These UATM systems would span across each city, and the air taxis would run between skyports, or landing zones, and would run similarly to how aeroplanes work with airports today. During cruise flight, all flights would be managed by a single “urban airspace service provider” (UASP), that would have the authority to adjust flight plans and track each individual flight to prevent collisions.

Flight Plan 2030 provides some insight as to how the urban air mobility industry would interact and collaborate with pre-existing dedicated air traffic control systems, such as conventional ATC agencies and Unmanned Traffic Management (UTM) systems for drones.

UAM Design Challenges

The next decade will be crucial to the growth of the UAM industry, wherein standards for safety, security, and performance will be defined. During this period, communication and data exchange standards will be created, and frameworks for airspace design and management will be decided. The upcoming developments in the next decade will determine how and if UAM will be implemented in different cities and countries, and its economic and social benefits as a mobility solution. Realising these benefits, however, require workable solutions that ensure safe airspace coexistence, as well as community acceptance. The successful design and implementation of a UATM system needs industry collaboration.

The urban airspace of the future will require accommodating the needs of all the stakeholders including low altitude small drone operators and General Aviation (GA) pilots of fixed-wing aircraft and helicopters, in addition to eVTOLs. According to ICAO (International Civil Aviation Organization) regulators, air navigation service providers (ANSPs) will require that flights remain safe, orderly, and efficient while minimising the impact on the airline and air traffic management (ATM).

As UAM flights begin, there is a need to collect data that will inform decisions that shape how UAM may grow to its full potential.

Air Traffic Management: Forecasters estimate that the global volume of air traffic is expected to double to 7.8 billion flights a year by 2036, a significant rise that will undoubtedly exert pressure on existing ATM resources, including the air traffic control workforce. As more eVTOLs become available, the needs of the UAM industry will become overwhelmingly challenging for current ATM systems.

Today, air navigation service providers (ANSPs) provide gate-to-gate ATM services for flights and are designed to manage flights between cities, as well as use radio and surveillance technologies for communication and to track aircraft that are usually spaced miles apart. Ground-based navigational aids serve as a backup to Global Navigation Satellite System (GNSS) surveillance information, but these are not suitable for UAM traffic surveillance. UAM systems will need more comprehensive navigation systems with smaller separation standards, because there will be a large number of eVTOLs taking off and landing from numerous skyports across a city. They will carry passengers and goods, fly in close proximity to buildings and other aircraft, hence will rely more on data link rather than voice communications as eVTOLs transition to autonomy, and operate in airspace adjacent to fixed-wing commercial aircraft.

UTM Framework: Another traffic management system being developed today is unmanned aircraft system (UAS) traffic management (UTM) for small UAS (sUAS)/drone operators and stakeholders to interact, share information, and maintain safe separation. Researchers and policymakers are refining the UTM framework to allow drone operators to use a decentralised information network that connects service suppliers (USSs) and ATM through a Flight Information Management System (FIMS).

While UTM holds much potential for drones, eVTOLs are expected to initially use voice communications. Presently, there is also no authority that controls or maintains situation awareness of drone operations in a given area. Hence, in case of an emergency, the UTM system will not be able to provide responsive services as they are not designed for mixed-equipage traffic over large urban airspace. UTM has much potential, but it is still a framework designed explicitly for unmanned aircraft and small drones in particular.

UATM System: UATM will be a system that will use strategically designed airspace structures and procedures to ensure urban flights remain safe and efficient while minimising the impact on ATM. These structures and procedures will be enabled by a number of technologies including communication, navigation, and surveillance (CNS ), autonomy, AI, and information exchange networks. The UATM has to be tailored to the needs of the urban area it serves, with the inputs from General Aviation (GA) community, skyport operators, and fleet operators. Every participant operating within UATM airspace will need to adhere to minimum operational performance standards. As the UATM system evolves, it may eventually integrate all UAS operations so that all low-altitude aircraft both piloted and autonomous, operate within a single system.

Mixed-Equipage Flight Integration: Traversing across an urban landscape requires traffic systems and different speed limits to keep everybody separated and moving, but more importantly, they mitigate risks for vehicles and pedestrians alike. Similarly, the urban airspace of the future will be structured with routes, corridors, and boundaries that will define where UAM aircraft may fly. The UATM system will be procedures-based first and foremost depending on predictable patterns generated from theses structured routes, corridors, and boundaries. Technologies such as CNS, AI, and automation also will be critical in enabling the UATM system.

Managing Urban Traffic: Flight Plan 2030 envisions that a single entity, an urban airspace service provider (UASP), will be responsible for managing low-altitude urban air traffic which has a number of stakeholders. However, unlike ATM operations, the UASP will not control traffic movements on or above skyports, but streamline operations of various eVTOLs and drones. As the single authority for managing the urban airspace on a daily basis, the UASP will have authority to open and close routes, grant flight authorisations, and execute a single, integrated flow management plan. The paper also says that each city and/or country will have a different approach for creating a UASP depending on the ANSP, regulations, policies, strategies, and resources. Nonetheless, a central authority is required to manage UATM airspace to ensure the safe and efficient flow of UAM systems.

UAM Safety Pillars

The Flight Plan 2030 identifies a number of pillars required for building a robust and resilient UATM system. As each airspace will be under the authority of a distinct law, regulation, and an ANSP, roles and responsibilities will be decided on a jurisdictional basis.

Airspace Structure: Airspace structures including routes, corridors, and boundaries, as well as procedures will enable existing traffic, such as fixed-wing aircraft and sUAS to coexist safely with eVTOLs maximising the capacity of urban airspace.

These predefined points will provide the much-needed predictability and support shared situational awareness for ATM and sUAS (Small Unmanned Aircraft System) operators. Given the complex mix of aircraft equipage, airspace structures will be critical for organising traffic and managing flows efficiently. UATM procedures will define how UAM flights will communicate, operate, and interact with the UASP and other stakeholders. Within these procedures, contingency plans will define stakeholders’ roles and responsibilities during off-nominal situations and emergencies. Although initially, eVTOLs will have little impact on urban airspace, well-designed airspace procedures will prove to be critical to mitigating risks, maintaining efficient traffic flow, and retaining community acceptance of the UAM industry when traffic increases to higher numbers.

Information Exchange: Information aids in informed decision making, and when all stakeholders can access timely, consistent, and accurate information they are able to collaborate confidently. With the status of skyports, corridors and routes changing rapidly, much like road signals and bus stops, the UATM airspace will be a dynamic place. To this end, information exchange is a foundational UATM service. The information exchange will derive data from numerous sources including aircraft sensors, weather sensors, skyports, pilots, ATM systems, and USSs. The weather data on the low altitude airspace will be particularly critical. The information exchange will also serve as a platform for interactions between ATM and UTM stakeholders, as well as act as an interface with ATM information systems like System Wide Information Management (SWIM) system. The data formats have to be standardised as they are to be exchanged across diverse platforms and needs to be consistent with ICAO plans. This huge amount of data exchanged may aid cities in dynamically allocating resources to current and forecasted conditions.

Flight Authorisation: Flight authorisations will provide fleet operators and pilots with a clearance to fly in UATM airspace. The authorisation will include an assigned route and, if necessary, a 4-D metering requirement. It will enable fleet operators and pilots to be confident that the flight is strategically deconflicted. The authorisation process will begin with stakeholders registering with the UATM system information, whereas skyport operators will register their skyport capabilities and provide real-time data about TOL pad availability through the information exchange. This readily available data will become the foundation for real-time flight authorisation after a flying or landing request is submitted. The information exchange will contain basic details such as departure point, destination, requested time of departure, and routes and corridors.

Once the flight authorisation is approved, it will be sent to the fleet operator and the pilot. The flight authorisation process will enable the UASP to anticipate traffic demands and strategically adjust routes and/or corridors, and it will help ensure that the UATM airspace is managed with a single strategic flow plan.

Flow Management: The UAM infrastructure envisions commuters to fly over road congestion, with the UATM flow management services that will keep UAM traffic moving. The primary goal of flow management is to optimise airspace capacity to minimise congestion and enhance safety as the traffic changes over the course of the day. Technologies like predictive analysis and time-based metering will be for monitoring traffic flows. The strategic flow management will include opening, closing, and moving routes or corridors as needed as per the flight conditions and stakeholders’ needs. Autonomous systems will monitor flights once they are airborne to ensure safe space is maintained. The automated systems will metre times, especially departure and arrival times of each aircraft will adjust dynamically in response to real-time data on weather, skyport status, passenger demands, and off-nominal situations.

Dynamic Airspace Management: The UATM airspace will be dynamic, demanding constant changes, and will require responsive and dynamic airspace management will be critical for continuous and flexible operations. A strategically positioned predefined airspace capable of supporting the varying needs of UATM stakeholders for daily operations enabled by the UASP that will open, close, and move routes, corridors, and airspace in response to traffic demands. At the same time, bring in necessary changes in flight routes and authorisation, when the ANSP restricts access to a section of airspace or creates a temporary flight restriction (TFR). Any emergencies and adjustments to the airspace structure will be communicated by UASP to all other stakeholders through the information exchange.

Conformance Monitoring: A critical part of UATM operations is conformance monitoring service, which will monitor eVTOLS from departure until landing by the UASP automation. With highly dynamic nature of the airspace means that if an aircraft fails to conform to a flight authorisation, particularly in a dense route or corridor, the failure may have a negative impact on safety and efficiency. A mix of beacon and sensor systems will monitor traffic and the location of aircraft in the UASP airspace and interact with counter-UAS systems to detect any unauthorised flights that may pose a threat to traffic. The UATM services will strive to be highly automated and will continue to evolve as the aviation industry develops new technologies. These improvements will improve navigation precision and conformance to 4-D flight requirements, which will make UATM safer for all stakeholders.

Periodically, particularly during emergencies and off-nominal situations, tactical conflict resolution will still be required. When these situations occur, the human operators in the UASP will assist pilots to execute contingency plans that protect passengers and crew from other aircraft and obstacles. All of these UATM services work as an interdependent suite that ensures the UAM system works efficiently, safely, and securely as operational conditions evolve.

A Future with eVTOLs

The UATM systems of the future will have to meet the high safety and security standards of the aviation sector to grow to its full potential. Without a safe, secure, and resilient UATM system, its benefits to the community and economy will not be fully realised. Evolving technological developments in aircraft and traffic management systems will continue to shape and reshape the industry. A future is possible where we can look up and see eVTOLs coexisting with other aircraft, where an on-demand flight can take us aloft and deliver us safely to our workplaces, families, and friends.

Reference Text/Photo:www.embraer.com

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