Strategies and Outcomes of New York Departure Reroutes for Route Availability Planning Tool Convective Impact Forecasts

When convective weather forms in the New York area it is a complex and ongoing challenge to coordinate an efficient and continuous flow of departures around operationally significant impacts. The New York airspace is a layered and complex network of restricted and constrained traffic flows that serves three major and several minor airports, making tactical weather avoidance a difficult task. While this dense airspace causes New York operations to be particularly vulnerable to convective impacts, even minor disruptions can cause ripples of delay across the National Airspace System (NAS). To address this, when convective weather impacts the airspace, New York TMCs utilize strategic and tactical rerouting to maximize departure throughput and minimize delays. Even seasoned TMCs are often challenged to identify the optimal timing and choice of reroutes since they must plan and coordinate reroutes in the face of significant uncertainty in weather impact forecasts, pilot and controller response, and demand.

The Route Availability Planning Tool (RAPT), used in New York since 2002, is a decision support tool for departure management that provides route-specific forecasts of convective weather impacts for a range of departure times. RAPT's route-specific forecasts directly support tactical route management by providing TMCs advanced notice of convective impacts that departing flights will encounter, enabling tailored avoidance of storms while maximizing awareness of available airspace. When RAPT forecasts severe impacts, traffic is managed by implementing a reroute operation, directing all traffic filed for that route to a different route. Optimally, reroutes would only be applied to flights whose route is severely impacted and the new route would impose minimal additional flight time and distance, have the capacity to manage the additional traffic, and be less impacted than the original. Ideally a flight would be rerouted at most once. The Integrated Departure Route Planning (IDRP) tool, used in New York since 2010, provides additional guidance to support these decisions, by integrating demand forecasts and reroute selection automation with RAPT.

However, the ability to optimize reroute strategies is limited by forecast uncertainty and existing forecast horizons. Reroute operations, typically implemented over the span of several hours, often require revision due to subsequent impacts on the reroute or restored availability of the original. Furthermore, reroutes may continue longer than necessary or may move traffic into airspace that is more impacted by weather or congestion than the airspace being avoided. Situational awareness of impacts over a longer time horizon would enable TMCs to more accurately customize their rerouting operations based on the impact.

This paper quantitatively identifies RAPT blockage thresholds for rerouting off individual routes through evaluation of flight tracks and RAPT blockages from 2011 through 2013. Then using these thresholds, the paper estimates achievable benefits for fine-tuned rerouting operations by identifying reroutes that would be recognizably unnecessary or poorly implemented with increased situational awareness. This evaluation will be done for multiple time horizons to identify the range of improvements achievable based on the availability of advanced weather information and for both perfect blockage forecasts and forecasts incorporating levels of uncertainty.

*This work was sponsored by the Federal Aviation Administration under Air Force Contract No. FA8721-05-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the United States Government.