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	+ Home Search Aviation Systems		Dynamic Weather Routes (DWR) Highlights - Fiscal Year 2013 Dynamic Weather Routes tool in operation at the American Airlines System Operations Center, Fort Worth, TX Severe thunderstorm activity is the leading cause of delay in the US National Airspace System. When such weather is present or forecast on preferred flight routes, weather avoidance routes are selected usually 1-2 hours before takeoff, and often include large buffers to compensate for forecast uncertainty. As flights progress, airline dispatchers and FAA traffic managers strive to find improved routes to reduce delay. However, operators are busy, especially during weather events, and may miss opportunities for more time- and fuel-efficient routes. Automation does not exist to help operators determine when weather avoidance routes could be modified or eliminated to reduce delay. NASA's Dynamic Weather Routes (DWR) tool is a real-time trajectory automation system that supports both airline dispatchers and FAA traffic managers. DWR is a search engine that continuously and automatically analyzes in-flight aircraft in en route airspace to find time- and fuel-saving corrections to weather avoidance routes. Route corrections are simple reroutes like those typically used in today's operations. DWR first detects flights with inefficient route segments included for weather avoidance; then the system automatically tries to find a more efficient time- and fuel-saving route around current and forecast weather. These advised reroutes save at least 5 minutes of wind-corrected flying time, while enabling users to visualize and modify proposed routes, evaluate flying time savings (or delay), proximity to predicted weather, traffic conflicts, downstream sector congestion, active special use airspace, and FAA routing restrictions. DWR testing and development continued at a fast pace in fiscal year 2013. After a successful initial operational trial at the American Airlines Integrated Operations Center (IOC) in Fort Worth, Texas, in the summer of 2012, NASA's DWR developers and researchers performed a laboratory evaluation of DWR at NASA Ames Research Center in February-March 2013 with six recently retired Fort Worth Center (ZFW) Traffic Management Coordinators (TMCs) and Area Supervisors. From the study, the DWR research and development team gained additional insight into operating concepts for the use of DWR with automated airline/ATC coordination, including when routes needed pre-coordination with the affected Centers or Command Center, as well as feedback on DWR routes previously found to be acceptable to American Airlines (AA) users during the experimental trial at the AA IOC. During the evaluation, the team found that DWR route advisories with large savings (e.g., 15-20 minutes or more), clearly triggered participants to question - without any prompting - whether or not existing weather-avoidance routes were still necessary. Further, simple automation that quickly displays a proposed reroute for approval seemed like the best way to streamline coordination and implementation of a DWR route request, and make FAA traffic managers aware of route restrictions that may no longer be necessary. In July 2013, a second software release of DWR was installed on the AA trial system. The new software selects DWR routes accounting for expected time required for flight dispatchers and pilots to evaluate, coordinate, and implement reroutes. It also enables users at the operations center to interactively examine the impact of maneuver execution delay on flying time savings, weather proximity, and traffic conflicts. Other new features include automation to prevent routes through narrow gaps in convective weather cells, and identification of flights on weather-avoidance routes previously prescribed by the FAA's ATCSCC. Several members of the NASA DWR team worked with 25 AA users and managers to review the new software, obtain user feedback, and discuss plans for the DWR trial going forward; support for DWR remained very strong and AA has now assigned staff to improve communication and coordination of reroutes between ATC Coordinators, AA's primary users of DWR, and individual Flight Dispatchers who send DWR reroutes to the flights. Data analysis of DWR reroutes shows an estimated actual savings of 360 flying minutes for 46 AA flights during the month of May 2013 which included several heavy convective weather days. Evaluation results for the period 31 July 2012 to 5 November 2013 show that 59% of routes advised by DWR and evaluated by AA users were rated acceptable. Potential savings for DWRs rated acceptable totaled 4,403 flying minutes for 808 flights. The primary conditions cited by AA users for not accepting an advised DWR were: proximity to merging arrival streams, routes through weather gaps, FAA routing restrictions (playbook or coded departure routes), and sector congestion. Staffing limits at AA prevented all advised DWRs from being evaluated by AA (25% were evaluated), so acceptable savings is potentially higher. An analysis of actual ZFW route amendments that followed DWRs rated acceptable by AA indicates an estimated actual savings attributed to DWR of 1,241 minutes for 260 AA revenue flights. Results from operational testing of DWR at AA show that AA revenue flights achieved 10% more savings on days where DWR was heavily used by AA vs. days where DWR was lightly used by AA. Due to AA staffing and other operational constraints, DWR is not used every day. Data from 34 heavy convective weather days in and around ZFW in 2013 were analyzed, all days with high potential DWR savings. On 16 heavy-use days (where greater than 20% of the advisories were evaluated), the estimated actual savings for 278 AA flights was 25% of the total savings advised by DWR. In contrast, on 18 low-use days (where less than 20% of the advisories were evaluated), the estimated actual savings for 289 AA flights was 15% of total savings advised by DWR. The ten percent of DWR-advised savings over the 16 heavy-use days equates to a savings of 586 flying minutes or about an $88,000 savings in operating costs, assuming an average total operating cost of $150/minute. Throughout FY 2013, the DWR concept and test results have been briefed to representatives from numerous airlines, aerospace companies, the FAA, and the US Air Force. Feedback from these stakeholders has been very positive, and NASA is currently working to determine how best to make DWR technology available for commercialization. DWR results were presented at the USA/Europe Air Traffic Management R&D Seminar in June 2013, and published at the Digital Avionics Systems Conference in October 2013. DWR was the subject of a NASA Aeronautics Research Institute (NARI) Seminar presented and web-cast in September 2013. A patent application for the DWR concept and prototype was filed with the US Patent Office in December 2012.
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