Convective weather, such as severe thunderstorm activity, is the leading cause of delay in the U.S. National Airspace System. Two NASA-developed tools – the Dynamic Weather Routes (DWR) tool and a national implementation of DWR called the National Airspace System Constraint Evaluation and Notification Tool (NASCENT) – will help pilots identify and evaluate opportunities for more efficient paths around convective weather and other airspace constraints. Dave McNally and Kapil Sheth are the lead developers of the technologies. DWR was tested operationally by a major US airline for three years.
NASA Tech Briefs: How are time and fuel saved with the DWR tool?
Dave McNally: Flight plans are selected by airline dispatchers and FAA traffic managers, usually one to two hours prior to takeoff. The FAA puts large buffers between weather avoidance flight plan routes and forecasted weather because of all the uncertainty. Often, these static, canned routes are not particularly well chosen to match the given weather of the day. There is no automation today to help operators, airline dispatchers, and FAA traffic managers identify opportunities where the weather has moved on or hasn’t materialized. DWR provides a continuous and fully automatic search for flights that are above 10,000 feet, looking for opportunities to fly more time- and fuel-efficient routes around weather. Advisories are posted to the user’s display.
NTB: What kind of data is driving these corrections and decisions?
McNally: The data feeds include 12-second updates of the en-route surveillance radar used by the FAA today. We have 5-minute updates of the Corridor Integrated Weather System, which models convective weather on a two-hour time horizon. [DWR] uses a national traffic feed for the sector congestion analysis. We have a one-hour update of the Rapid Refresh wind data from the National Oceanic and Atmosphere Administration, and then a database of aircraft performance models that is mostly pertinent to climb and ascent trajectories. We roll all that together, and we build updated trajectories of all the flights in the sky.
NTB: What is NASCENT, and how does it relate to DWR?
Kapil Sheth: NASCENT adds other capabilities. It extends the Center-based scope of DWR to the national level, through the use of a novel technique. Also, it not only avoids convective weather, but proposes new routes simultaneously around special-use airspaces (e.g., military operation areas), or any other constraints the users may prescribe (e.g., turbulence). In NASCENT, all the airspace constraints are represented as polygons and are avoided by the rerouting algorithm.
NTB: What’s next in the development of these technologies?
McNally: We want to have the capability running in the FAA centers, and have smooth coordination between airline operators at their dispatch operations center and the FAA traffic management units. That could result in more actual savings.
Sheth: The FAA recognizes the value of such a tool. They realize the inefficiencies that routes can introduce. Airlines, too, are saving so much fuel. From NASA’s perspective, it also helps the environment. If you waste an hour of extra flying, you’re just adding that much more carbon and other emissions to the atmosphere.
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