How will the air traffic management (ATM) operational concept and system architecture evolve between now and 2050? What changes are required to be implemented in SESAR to ensure a smooth transition? These are the questions FLITE (Future Long-term ATM concept, Infrastructure, Technologies and operational Environment), a recently completed exploratory research project, sought to answer.
Over the next four decades, more complex air travel scenarios are expected to emerge in Europe. The future vision of air travel in Europe expressed in Flightpath 2050 is to provide door-to-door transport within Europe capped at 4 hours (90%) and to execute all flights with delays not exceeding 1 minute under all weather conditions. The vision further includes dynamic network reconfiguration, 24 hour efficient airport operations and coherent ground infrastructures, including vertiports and heliports. The achievement of this vision will require fundamental changes in the air transport system.
Not surprisingly, the integration of air vehicles with varying levels of performance and automation into the same airspace will result in a significantly higher density of traffic. In light of these challenges, the FLITE project evaluated how the target SESAR operational concept and technologies will need to evolve in order to accommodate these scenarios while at the same time enabling 90% of passengers within Europe to complete their door-to-door journeys within 4 hours.
Carried out jointly by Imperial College London and ISA Software, FLITE identified three key operational challenges in areas: gate-to-gate, passenger handling and airport access. Furthermore, a number of associated technological challenges were also identified:
Overcoming airport capacity constraints
From a gate-to-gate perspective, FLITE confirms that airport capacity shortage remains a key issue. The SESAR concept includes several improvements that FLITE considers key for increasing runway capacity, such as use of variable glideslopes or offset thresholds. In addition, FLITE proposes that linking existing satellite airports in the vicinity of hubs with seamless high-speed terrestrial connections would offer a significant potential to address the capacity crunch at the busiest airports. The SESAR research into new concepts to mitigate the risk of wake vortex may also enable the enhancement of runway capacity through the use of larger aircraft, . Additionally, the SESAR work on integration of rotorcraft should be extended to include new vertical take-off and landing (VTOL) approach procedures, which will not only alleviate runway capacity, but also allow for a much better use of terminal manoeuvring airspace by significantly increasing the number of available approach procedures into the airport.
Integrating a diverse fleet of air vehicles
The future fleet will be more diverse than it is today, and a growth of personal air vehicles (PAV) can be expected. This will pose additional challenges to the ATM system, both in terms of handling aircraft with a wider range of performance characteristics and in terms of needing to allow ad-hoc operations to accommodate the needs of PAVs, which will place a greater focus on the flexibility key performance area (KPA). For this reason, FLITE suggests that the future SESAR concept aims at defining solutions that allow increased flexibility in the ATM system in preference to those that require that a rigid pre-agreed plan is followed by all stakeholders.
Airspace capacity is also a key limiting factor. FLITE recommends that the future SESAR concept includes the reduction of radar separation minima, and the research ambition be the identification of opportunities for allowing separation minima as low as 1NM between certain aircraft pairs in certain geometries.
Including passenger processes
Passenger movements currently incur delays that would prevent Flightpath 2050 performance targets from being met. FLITE assessed potential solutions such as increased levels of automation in passenger processes at the airport (including baggage check, customs and security screening) to enhance a smooth passenger flow through the airport and thereby reduce transit times. The current SESAR concept considers of passenger processes as an input from airport collaborative decision making (CDM) processes into the ATM system. FLITE recommends that this connection is enhanced in the future, potentially including the possibility that airports consider at a tactical level ATM system inputs into their passenger processes.
Defining a total transport system architecture
A further key limitation pinpointed by FLITE for attaining the FLIGHTPATH 2050 door-to-door travel time target is the significant travel time of passengers between their home and the airport, and vice versa. The integration of airports within an overall European transport network, including autonomous vehicles, personal air vehicles and high-speed trains, is one of the core enablers to achieve the efficiency and performance targets for the year 2050 and beyond. As part of this integration, FLITE recommends that a high-level transport management body is given the responsibility to design a total transport system architecture and the mobility performance assessment, as well as the supervision of the holistic planning and optimisation of that integrated system in order to deliver the promise of an interoperable, predictable, flexible, accessible, resilient and cost-efficient transport network.