The Rise of Urban Airports
The topic of Advanced Air Mobility for people and cargo has hit the headlines in the last 12 months. Triggered by an industry prioritising a commitment of sustainable aviation operations as we rebound from the impact of the pandemic, the promotion of electric and hydrogen aircraft has got increased attention. This is evidenced by the significant number of global manufacturers progressing development of new electric Vertical Take-off and Landing, or eVTOL, vehicles. Will eVTOLS become a reality? Recent announcement by EASA that certification of eVTOL aircraft by 2024 highlights the progress the industry is making towards commercial operations.
Operational scenarios for these eVTOL aircraft will change the urban environment, including intra-city transport to hot-spots like airports, train stations, sports and entertainment stadiums or other high interest areas within a 200km range.
Urban airports, also known as vertiports, will provide the infrastructure and landing sites for vertical take-off and landing. To facilitate the perceived demand in urban trips requires a solution to locate vertiports, potentially dozens, within and surrounding the urban environment. This scenario is progressing in Singapore under a partnership with Skyports and Volocopter. And such scenario raises many questions.
How to Manage Urban Traffic?
How to design airspace and vertiport infrastructure? What air traffic management services are required? Is current policy for urban planning appropriate? And how to enable information sharing to ensure undisrupted, predictable and punctual travel?
As a priority, the industry must also understand how they will ensure safety of operations and manage contingency scenarios. For example, how do you allocate and manage alternate landing sites for diverting aircraft. The approach to safety will challenge us in urban environments with tall buildings and other static and dynamic infrastructure.
Managing traffic flows will be critical for the eVTOL operations business case. In addition to efficiency and safety, there will be a significant cost impact for an aircraft to be holding in case no landing or parking capacity is available. Therefore, a network approach to managing capacity and efficiency of urban airspace will be required. It is likely that an Urban Airspace Authority (UAA) is needed to provide the services to deliver air traffic safety and efficiency.
Urban Airspace Authority (UAA)
The primary role of the UAA should be to manage urban airspace complementary to ANSP managed airspace. Urban airspace operations should be considered landside with its close proximity to terrain, buildings and structures. Urban traffic can only enter managed airspace through agreed transit points or route intersections, through agreed procedures.
The UAA will likely need to obtain and maintain an autonomous and real-time perspective on current and short term traffic demand, to manage capacity and restrict or re-route traffic where needed. To achieve that, vehicle performance characteristics, 4-dimensional (4d) route planning and route intent needs to be available and updated, and confirmed 4d-profiles monitored for conflicts with other traffic intent.
To realise automated and real time balancing of traffic demand and capacity, with focus on critically limited urban airspace, enhanced and automated procedures known within the traditional airport environment as Collaborative Decision Making (CDM) could provide a solution.
In an Urban-CDM environment, each eVTOL vehicle provides coordinates for their destination for which a 4d-profile will be generated autonomically through real-time automated coordination with the UAA. The confirmed 4d-profile will be an efficient and de-conflicted route to the destination with a time window in which is it guaranteed to be safe. The 4d-profile is reserved and cleared for one dedicated vehicle in the Urban Airspace to avoid other traffic.
Traffic changing destination or starting outside the time window will be offered an alternative 4d-profile. The generated 4d-profiles shall at all time ensure safe routing, sufficient capacity at destination or offer alternative destination capacity for the vehicle to accept or reject.
Non-compliance or capacity waste will result in various alerts to regulating authorities and consequences for vehicle operators. Additionally, other traffic is immediately alerted to detection of non-adhering vehicle, and an alternative route offered to mitigate impact. This requires surveillance and interfacing functionality in all vehicles subject to the same Urban Airspace.
Seamless integration between Urban and Hub Airports
Urban traffic that is bound for, or crossing, restricted airspace, such as an airport with traditional aviation, will require parking space similar to taxi’s outside a terminal. Kiss and ride, short and long term (vertical) parking require different low altitude landside routes to and from the site, avoiding any intersection with classic aviation on the airside of the airport.
Use of 4d-profiles and management by the UAA requires new mandate of authorities, close cooperation and interaction with local Air Navigation Service Providers, and operational concepts for interoperability and specific urban traffic scenarios.
Preparing the Human for Automation
The urban airspace will become a complex series of aircraft executing their 4d-profiles. This could be imagined as a complex tangled spaghetti. The ability of the human to comprehend this environment let alone manage it will be limited, if not impossible. It can be reasoned and even assumed that automated or even autonomous flight, to enable self-separation between vehicles, is required to assure safety of operations.
Autonomous flight will also deliver more predictability enabling reduced buffer space for cleared profiles. As we transition to autonomous flight the role of the human in oversight and contingency scenarios must be considered and the future traffic management service must continue to be designed as a single joint human and machine system.
Time to Validate the Scenarios
The introduction of new vehicles into the urban environment requires innovation in solutions that deliver predictability and contribute to a safe environment for urban traffic. Real time Urban-CDM is pre-requisite to unlocking to the potential. Urban CDM is the process of humans entering demand and intent whilst automation acts real time using standard interfacing to confirm a safe 4d-profile.
Standards, procedures and technology exist in todays’ aviation system that can be used to create and operate Urban-CDM for eVTOL in an UAA managed airspace. Solutions to interconnect regional airports using CDM principles is an enabler for Urban-CDM. It is time to organise the trials and validate the urban traffic scenarios of the future.
At To70, we have been closely involved with developments in the GSE market. We collaborate with universities, airports and GSE manufacturers to determine how the electrification of the ground segment can contribute to a more sustainable and efficient mode of operation. Contact us if you want to know what the possibilities are for your airport.
About To70. To70 is one of the world’s leading aviation consultancies, founded in the Netherlands with offices in Europe, Australia, Asia, and Latin America. To70 believes that society’s growing demand for transport and mobility can be met in a safe, efficient, environmentally friendly and economically viable manner. To achieve this, policy and business decisions have to be based on objective information. With our diverse team of specialists and generalists to70 provides pragmatic solutions and expert advice, based on high-quality data-driven analyses. For more information, please refer to www.to70.com.