Generating Realistic Reroutes to Assess Air Traffic Impact of Blocked Airspaces

Demand for airspace access has been on the rise due to an increasing number of new entrants such as Space Operators, Unmanned Aircraft Systems (UAS), and Balloon Operators. To accommodate operations such as space launches in the National Airspace System (NAS), the Federal Aviation Administration (FAA) may strategically route traffic around airspaces to ensure operational safety. As the frequency of these activities increases, there is a need to deepen collaboration and transparency between stakeholders regarding airspace usage. A primary need to support this collaboration is the ability to quickly assess traffic impacts due to flights rerouting around airspaces closed due to upcoming operations. Using such a capability, a space operator may be able to adjust their launch and reentry operations plan to have minimal airspace system impact, and a traffic manager may be able to quickly assess the impact of last-minute launch time changes. This paper presents a rapid reroute generation algorithm that models the path that flights are likely to take around blocked airspaces, that reflects the strategic air traffic flow management strategies used to accommodate such a constraint. The model systematically considers several rerouting strategies, starting with the routes available in the National Playbook and Coded Departure Routes (CDR) to find flight paths clear of the closed airspaces. Since many of the routes in the playbook definitions do not originate or terminate at airports, an algorithm to detect historical tracks with a high conformance to such routes is developed to select flight tracks which act as proxy for such routes. Additionally, five years of historical track data is analyzed to generate dominant clusters of flows between all city pairs, which provide alternate paths options around blocked airspaces. Finally, a Dijkstra's k-shortest path algorithm-based method is used to model tactical deviations of flights around blocked airspaces. The paper describes the model, data sources used, validation methodology, the accuracy of the results as well as the model's limitations. The research presented in the paper may be used to develop capabilities to assist airspace users to make more informed decisions concerning the timing and location of their operations within the NAS and promote cooperation and collaboration between the increasing number of new entrants and traditional NAS users.