The sectorless concept in air traffic control (ATC) represents a transformative approach to managing airspace, moving away from the traditional sector-based model towards a more dynamic and efficient system. Below is a short history of its development:
The Traditional Sector-Based Model
In the early days of aviation, airspace was divided into fixed sectors, each managed by a dedicated team of air traffic controllers. This system was designed for simplicity and local accountability. However, as air traffic volumes increased, the limitations of this model became apparent. Sector boundaries often caused inefficiencies, such as imbalanced workloads, high amounts of coordination between sectors and delays during periods of high traffic. Despite these challenges, the current system in the EU still follows this approach, although it allows for the merging or splitting of sectors within a specific framework.
Introduction to Sectorless ATM
The concept of sectorless Air Traffic Management (ATM) was first proposed by EUROCONTROL in 2001 (Vu Duong et al). This approach aimed to address the growing challenges in air traffic management by reducing the dependency on fixed airspace sectors. The idea gained further attention when Riviere introduced a route concept in 2004, exploring the potential benefits of this system.
Early Research and Proof of Concept (2010–2012)
From 2010 to 2012, the German air navigation service provider DFS, in collaboration with the German Aerospace Center (DLR), began conducting proof-of-concept simulations as part of the national project Airspace Management 2020. These simulations demonstrated the principal feasibility of sectorless ATM and identified several benefits. The radar display was divided into tiles, each showing the aircraft under the controller’s responsibility, with the tile centred on the aircraft.
Key assumptions included 100% aircraft equipage with data link for controller-pilot communications and downlink of aircraft trajectories. The results indicated that the role of the controller would change significantly: there would be less reliance on radiotelephony, reduced coordination, and the potential to control up to seven aircraft simultaneously. However, situational awareness emerged as the key limiting factor, suggesting that improvements to the Human-Machine Interface (HMI) and automation could enhance performance. The simulations also highlighted the need for better assistance in finding conflict resolutions, particularly for short-term conflicts.
The TeFiS Project (2014–2017)
Between 2014 and 2017, the German government funded the TeFiS project (Technologie für Flugverkehrsmanagement in großen Strukturen), which further explored sector-less ATM in the German upper airspace above FL 375. This project involved eight weeks of real-time simulations aimed at validating the concept under more realistic conditions, such as using current voice communications instead of data links and the lack of airborne trajectories for conflict detection and resolution.
The project also focused on external coordination, which was not assessed in previous studies. Several HMI modifications and controller tool adaptations were required for the validation. Additionally, different strategies for allocating aircraft to executive controllers were explored. The findings reaffirmed earlier conclusions: the work of the controller would change significantly, with less radiotelephony, reduced coordination, and the potential to control up to seven aircraft simultaneously. However, the main limiting factor remained situational awareness, necessitating further research into improving the HMI and automation, particularly for conflict resolution.
SESAR 1 and the Continued Development of Sectorless ATM (2015)
In 2015, SESAR 1 published a task force report summarizing the status of sectorless ATM. The report concluded that, while no major barriers to research and development were identified, several key considerations remained, particularly around coordination with adjacent Area Control Centres and issues related to air-ground communication frequencies.
SESAR 2020 and the Flight Centric ATC Concept (2017–Present)
The work on sectorless ATM continued in the SESAR 2020 program, using the new name of Flight Centric ATC (FCA). The concept was initially explored in Project PJ.10-01b in Wave 1, followed by PJ.10-W2-73 FCA in Wave 2. These projects brought the FCA concept to a maturity level of Technology Readiness Level 6 ongoing (TRL 6-ongoing). The SESAR 3 FCA project aims to build on the work from SESAR 2020 and address the remaining aspects that could not be fully explored due to the disruptions caused by the Covid-19 pandemic. The goal is to bring the FCA concept to TRL 6, ensuring its readiness for broader implementation in the future.