ALBATROSS is an ambitious very-large scale project which is demonstrating energy-efficient aviation using a combination of SESAR solutions. But what does the most eco-friendly flight look like? Andreas Linnér, Novair, is gatekeeper within the project for the overall ALBATROSS concept of operations (CONOPS) and explains what it means to fly the optimum flight in terms of sustainability.
What is the main focus of the ALBATROSS CONOPS?
Well, there are actually two main focuses of the ALBATROSS CONOPS:
First, the ambition is to define the most optimum flight possible, as seen from a CO2 perspective. In theory, this refers to a gate-to-gate flight flying without any constraints – ATM or otherwise - at optimum speed and altitude, using the most CO2-efficient trajectory (including positive effects of atmospheric conditions, for example, wind) and thereby emitting no additional CO2 than minimum produced for that particular flight. It may seem like an easy task, but once you dig into the subject, there are a myriad of questions you have to consider. For example, how do you define the most CO2-efficient trajectory if the aircraft takes off in a different direction than the destination, i.e., is it possible to define a perfect turn? What speed would be the most optimum in climb, cruise and descend? Should you consider step climb or cruise climb?
Secondly, once the optimum flight is defined, the other main focus is to identify any constraints counteracting this theoretically optimum flight. This is achieved by comparing real flights for a specific city-pair with the optimum flight for the same city-pair. This enables the difference in CO2 emissions to be measured and constraints to be identified, which prevent optimal flying. The next step is to find solutions to overcome these constraints. ALBATROSS is a demonstration project, aimed at finding quick wins for swift implementation, where feasible. What we have discovered so far is you need to take many small, but comparably simple, steps to achieve this. Essential as well is the cooperation of all involved stakeholders to contribute to find practical ATM solutions to improve the airspace users’ trajectories. One example, is the introduction of dynamic route availability document (RAD) restrictions management, aspiring to require the utilization of RAD restrictions only when really necessary, according to the prevailing traffic situation. This dynamicity allows airspace users to take benefits from notified relaxation of the identified restrictions, facilitating the improvement of the trajectories already in the planning phase. Simple - yes, but easy to implement in daily operations and if many of these, the result starts to emerge – more and more eco-friendly flights.
ALBATROSS is carrying out a range of demonstration exercises – how are these reflected in the concept of operations?
The CONOPS focuses on finding the most optimum trajectory for a flight from A to B. The demonstration exercises will use this optimum trajectory as the reference to find constrains, i.e., where does the real flight differ from the optimum flight in terms of CO2 emission? Then, if there are opportunities to find any quick wins for this flight, the trajectory can be improved.
What is/was the main challenge to make up a proper concept of operations for ALBATROSS?
As the project kicked off early 2021, the main hurdle has of course been the COVID-19 situation. The CONOPS is the result of collaboration, discussions and brainstorming between experts from all domains of the aviation community and any restriction to meet face to face is a challenge. We’ve also had many discussions on how to balance theory with the real world. Defining an optimum flight totally disconnected from today’s environment (like the space shuttle) is of no use. Still, it needs to be unconstrained and as eco-friendly as possible. Like the albatross bird!
This project has received funding from the SESAR Joint Undertaking under the European Union's Horizon 2020 research and innovation programme under grant agreement No 101017678