Integration of the next generation aircraft for zero/low emission aviation

To significantly advance the following development priority:

• AR-3 Integration of the next generation aircraft for zero/low emission aviation.

1. Integration of the next generation aircraft for zero/low emission aviation

The future vision of air transport without net carbon emissions supporting the Green Deal goal includes the introduction of hydrogen (combustion and/or hydrogen fuel-cells), battery-electric and hybrid-electric powered aircraft. These aircraft are currently in the development phase, and their entry into service is not expected until the next decade. Once operations start, their numbers are expected to increase rapidly, which is why the ATM Master Plan sets an objective to ensure that the ATM system is ready to fully integrate them from the start. The goal is that these operations can take place safely, efficiently and without a disproportional impact on conventional (i.e., current generation of kerosene-powered aircraft) air traffic operations.

It is anticipated that these new aircraft will present challenges to ATM in the following areas:

• Evolution of the fleet-mix with increase diversity in aircraft performance: the new aircraft present different performance envelopes than current aircraft for example in terms of cruising levels, cruising speed, final approach speed and rates of climb and descent. This is a challenge for ATM because operations are currently organised considering the current fleet mix.
• Different requirements for airport operations (e.g., turnaround times, ground handling, etc.), which will affect the airport operations plan (AOP)/network operations plan (NOP) integration concepts (e.g., new / adapted airport infrastructure longer turn-around times, new refuelling processes, etc.).
• The new aircraft will have lower range and will also carry a lower number of passengers per flight, which may lead to an evolution of the traffic demand (e.g., new city pairs, more flights to carry the same number of passengers, etc.).

This analysis must take into consideration the different aircraft type / models and propulsive systems under development. The objective of the research is to collect requirements for the seamless integration of the new models / propulsive systems in European airspace, and where appropriate provide recommendations for ATM developments (potentially proposing roadmap if appropriate), addressing, for example:

• Trajectory based operations (TBO) already provides a framework to allow the optimisation of individual flights powered by conventional fuel or sustainable aviation fuel (SAF). There is a need to assess how this framework can support the optimisation of low or zero-emissions aircraft, and where necessary propose enhancements.
• Applicability of new ATM concepts supporting sustainability (e.g., green taxi, wake energy-retrieval, etc.).
• Adaptation of ATM platforms to support the evolution of the fleet to include increased diversity of performance envelopes.
• Potential impact on airports (including regional airports) and AOP/NOP integration due to the impact on the predictability of airport operations (e.g., due to longer turnaround, changes to airline scheduling patterns, new flight planning/flight plan acceptance processes, new fuelling procedures, new engine start-up requirements, etc.).
• Evolution of aircraft design characteristics, for significantly increased fuel efficiency and minimising emissions, for example with new generation single-aisle model for long-haul, triggering the need for additional wake turbulence research in order to define criteria and guidelines establishing boundaries between wake categories (e.g., around medium aircraft) regarding refined decay characterisation and initial vortex spacing factor, for facilitating design and certification in relation to optimised assignment to advanced wake separation schemes (RECAT-EU or Pairwise, complementing reference analysis), and limiting potential impact on airports capacity and on operational efficiency, related to arrival and departure runway throughput.
• Different propulsion characteristics and failure cases could impact take-off and/or landing distances, heavier H2 aircraft (at landing) could drive higher approach speeds or increased wake vortex class compared to equivalent Kerosene powered aircraft, etc. There is a need to assess the potential impact on route design (e.g., standard instrument departure routes (SID) and standard instrument arrival routes (STAR) design, approach procedures, RNP specifications, etc.).
• Potential impact on traffic synchronization (e.g., sequencing and separation of traffic with different descent / approach performance, take-off / climb characteristics, etc.).
• Potential impacts in terms of traffic demand (e.g., less capacity per aircraft in terms of passengers) as well as complexity and finally capacity to manage aircraft with different performances.
• Impact on airspace management, network management and traffic flow management processes due to the different optimum cruise altitude/speeds for the new aircraft and propulsion concepts (e.g., impacts on airspace configuration, air traffic flow and capacity management (ATFCM) processes, etc.).
• Prediction of the evolution of traffic demand, due to e.g., shorter routes, more flights to accommodate the number of passengers. The impact of different policy scenarios could be considered (e.g., short-haul ban, multimodal regulations, etc.).

Research also includes the definition of a potential future scenario(s) representative of future demand for 2035 including:

• Different combinations of future fleet composition, models / propulsive systems with different capabilities (payload / range / speed), with expected entry into service (EIS) by 2035 and different ramp-up / infrastructure scenarios, covering the Hybrid-Electric Regional, short medium range aircraft (SMR), a Hydrogen-powered options considered in Clean Aviation.
• Different future ATM concepts expected to be implemented by 2035, considering the impact of the variety of vehicle performances and their impact on traffic management.

Oher future scenarios could address a longer-term vision (e.g., 2040+ (SMR H2), 2045+ (Long-range aircraft (LR)) combined with more innovative Phase D ATM operational concepts.

Research shall evaluate the impact on performance such as the reduction of the CO₂ emissions, the environmental impact of H₂ and water (contrails) from hydrogen-powered fuel cell systems on at fleet scale, etc considering the scenarios defined above. Research may also address the impact on other relevant key performance areas (KPA) such as capacity, access and equity, etc.

Research shall identify the needs for the adaptation of the regulatory framework for air navigation and aerodromes (including new requirements, means of compliance) and the related safety standards.

The research shall consider the work performed under the AZEA initiative (i.e., CONOPS) and the Clean Aviation Joint Undertaking programme, and coordinate as necessary with EASA to ensure that safety concerns have been sufficiently addressed.