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This document presents a preliminary analysis of potential departure delay reduction benefits in New York as the result of the use of the Integrated Departure Route Planning (IDRP) tool during convective severe weather avoidance programs (SWAP). The analysis is based on weather impact and air traffic data from operations between May and September 2010 in the New York metroplex region. Two methodologies were employed in the analysis: "flight pool" and "resource pool." In the flight pool methodology, individual flights with excessive taxi times were identified, and opportunities to find potential alternative reroutes using information that IDRP will provide were assessed. In the resource pool methodology, route impact minutes were tallied over several days, based on the judgment of a human analysis, and opportunities to recover capacity lost to route impacts via IDRP-identified reroutes were estimated. The flight pool methodology estimated that approximately 156 hours of delay could be saved through the use of IDRP over a full SWAP season. The resource pool methodology estimated that approximately 15% of capacity lost to convective weather impacts could be recovered via IDRP-based reroutes. It should be noted that the potential benefits are based on several assumptions that are described in detail in the text of the report. The estimation of delay savings due to reroute is also speculative. It is very difficult to ascertain when the assignment of a reroute actually makes use of underutilized capacity and when the reroute simply shifts the problem from one congested resource to another. Further research is needed to develop reliable metrics that can guide the assessment of reroute impacts on overall traffic management performance.

The Route Availability Planning Tool (RAPT) operational prototype was deployed to Chicago in the summer of 2010, the first RAPT deployment outside of the New York departure airspace for which it was originally developed. The goal of the deployment was to evaluate the adaptability of RAPT's airspace definition, departure management and weather impact models to different terminal areas throughout the National Airspace System (NAS). This report presents the results of a summer-long evaluation of the Chicago RAPT operational prototype, in which the performance of RAPT algorithms and the effectiveness of the RAPT Concept of Operations were assessed. The evaluation included observations made by researchers simultaneously stationed at O'Hare terminal (ORD), the Chicago TRACON (C90), and the Chicago Air Route Traffic Control Center (ZAU) during several days of convective weather impact and post-event analysis of air traffic data from the Enhanced Traffic Management System (ETMS) and RAPT weather impact predictions and departure management guidance. The study found that significant departure delay reduction could be achieved through the use of RAPT in Chicago, and that RAPT effectiveness in "typical" corner post airspaces like Chicago could be further increased with some modifications to the Concept of Operations, user training, and site adaptation.

A method coupling field evaluation with operations data analysis is presented as an effective means to functionally evolve a decision support system. The case study used to illustrate this method is the evaluation of the Route Availability Planning Tool (RAPT), a decision support tool to improve departure efficiency in convective weather in New York air traffic facilities. It was only through a combination of quantitative performance data analysis and field observations to identify key elements of the decision making process that the designers were able to determine the most critical departure management decision requiring support, leading to significant improvements in departure efficiency.

TCAS behavior in New England airspace is being monitored and analyzed, making use of an omni-directional 1030/1090 MHz receiver. The receiver system, located in Lexington, MA, and operated by M.I.T. Lincoln Laboratory, is used to record Resolution Advisories (RAs). Omni-directional receptions make it possible to examine the air-to-air messages exchanged between aircraft for coordination of RAs. Omni-directional reception rates are also being studied. THe results indicated the percentage of aircraft that are TCAS equipped and the percentage of received signals that originate from TCAS and other systems. A third aspect of the program evaluates the availablity of 1090 MHz Extended Squitter data for use in collision avoidance systems. Data is recorded continuously, and the busiest periods are selected for focused attention.

When operationally significant weather affects the National Airspace System (NAS) a Severe Weather Avoidance Program (SWAP) is initiated. Each SWAP event is a unique mix of demand, weather conditions, traffic flow management (TFM) initiatives and traffic movement. Following a SWAP, the day's events are reviewed and the TFM initiatives used are evaluated to understand their impact on the traffic flows, benefits, and disadvantages. These analyses require an accurate representation of the conditions during SWAP and objective, data-driven metrics to determine the effectiveness of the implemented TFM initiatives, and to identify opportunities for improved decision making in future events. As part of the ongoing development and evaluation of the Route Availability Planning Tool (RAPT), a departure management decision support prototype currently deployed in New York, several detailed metrics were developed to streamline these analyses. This paper focuses on metrics that address the most significant concern regarding departure flows from New York airports: the timely reopening of departure routes that have been closed due to convective weather impacts. These metrics are derived from two datasets: flight tracks from the Enhanced Traffic Management System (ETMS) to monitor the flight traffic, and route blockage from the Route Availability Planning Tool (RAPT) to determine the impact of weather on routes. RAPT automatically identifies Post-Impact-GREENs (PIGs) - the period of time when routes are clear ('GREEN') after being blocked by convective weather. Identifying PIGs early is a key element of the RAPT concept of operations, which enables traffic managers to restart traffic flow sooner along these routes, alleviating backed up ground conditions and reducing delay times for waiting flights. An automated system, that correlates PIGs identified by RAPT with departure traffic flows, calculates both the time from the appearance of each PIG until the first departure along the PIG route, and the departure rate on the route during the PIG period. Short times to first departure and high departure rates during PIGs indicate efficient departure management during SWAP. Arrival aircraft deviating into departure airspace is also managed by closing the departure route until the danger from incurring flights has passed. Arrival incursions are sometimes recorded in the National Traffic Management Log (NTML), but the extent to which the deviations occur is unmeasured. Lack of details regarding deviations limits evaluation of implemented responses and alternative actions. New algorithms comparing clear weather vs. SWAP traffic flows enables the locations and durations of incursions to be identified. Exact figures detailing incursions allows for thorough review as well as recognition of areas of frequent incursions and the potential for developing a targeted response for like situations. Full flight tracks of arriving and departing flights provide significant insight into the status of the NAS. During SWAP when the airspace capacity is decreased and airport operation rates are limited, airborne aircraft by protocol receive priority. Arrival numbers can completely dominate operations at these times both in the air and on the ground, draining the resources available for departures in particular flows or for an entire region. To convey cases where departure infrequency results from these conditions, arrival and departure counts grouped according to direction of travel are calculated on an hourly basis. Results from the automated analysis are made available on the RAPT Evaluation and Post Event Analysis Tool (REPEAT) website by 7AM ET for the FAA Northeast tactical review teleconferences, and are being tracked over the convective season for further analysis of operational performance. This paper will present the techniques used in the automated system and initial results from the analysis of operational data.

Time-based flow metering (TBFM) of traffic to capacity-constrained areas such as airport runways and arrival fixes is considered a key element of the Next Generation (NextGEN) Air Transportation System operational concept for managing high density air traffic. The principal operational TBFM system today is the Traffic Management Advisor (TMA). TMA is used to optimize the flow of aircraft through various control points (e.g., arrival fixes, final approach fixes, and runway thresholds) so as to maximize airspace capacity without compromising safety. TMA makes continuous predictions of aircraft Estimated Time of Arrivals (ETAs) at various metering points along the flight's trajectory. Scheduling algorithms use the ETAs to compute Scheduled Times of Arrival (STAs) for each aircraft to specific scheduling points. The desired change in aircraft arrival time to the meter fix is provided to en route controllers who then accomplish speed and/or trajectory changes such that the plane passes over the arrival fix at the desired time. The required arrival fix time adjustment is continually updated as the plane proceeds to the arrival fix to provide closed loop control. During non-convective weather, TMA usage has resulted in increased capacity, reduced aircraft fuel burn, and decreased delay. If significant convective weather is present, the TMA software currently still assumes that an aircraft will fly the normal fair weather trajectory to a metering fix. However, if an aircraft deviates around a storm, the flying time to a metering point will generally be different from the fair weather flight time. Therefore, the TMA ETAs will be in error. Currently, the TMA usage is often halted during convective weather events because the arrival time adjustments provided to the controllers may be unmanageable or in error. A study is underway to determine the potential benefits derived from various approaches to integrating weather information from the Corridor Integrated Weather System (CIWS) with TMA. Our focus is on near term weather-TMA integration capabilities that would provide enhanced decision support for the operational community that is successfully utilizing TMA in non-severe weather and/or seeking to increase its operational utility in severe weather. As part of this study, and in conjunction with case study analyses of TMA actions and air traffic operations during convective weather, Subject Matter Experts (SME) from the National TMA Workgroup and select FAA facilities were interviewed to determine TMA fair-weather practices and to identify current TMA capabilities and limitations during weather impact events. The SMEs were also asked to prioritize TMA weather integration needs and to discuss specific weather integration options for the TMA displays. Real-time observations of TMA operations during convective weather were also conducted at Atlanta (ZTL), Boston (ZBW), and Chicago (ZAU) Air Route Traffic Control Centers (ARTCC) to examine (a) the common TMA control actions executed to meter flows during adverse weather, (b) when and why the TBFM becomes unusable during convective weather, and (c) which approaches to providing integrated weather-TMA information would most effectively extend the current TMA capabilities and increase ATM efficiency. The paper will describe initial results of the study including specific options for TMA-CIWS integration and the anticipated operational benefits for these options.

Airspace capacity constraints caused by adverse weather are a major driver for enhanced Traffic Flow Management (TFM) capabilities. One of the most prominent TFM initiatives introduced in recent years is the Airspace Flow Program (AFP). AFPs are used to plan and manage flights through airspace constrained by severe weather. An AFP is deployed using "strategic" (i.e., 4-6 hour) weather forecasts to determine AFP traffic throughput rates. These rates are set for hourly periods. However, as convective weather continuously evolves, the achievable en route airspace throughput can fluctuate significantly over periods as short as 15-30 minutes. Thus, without tactical AFP adjustments, inefficiencies in available airspace usage can arise, often resulting in increased air traffic delay. An analysis of AFP usage in 2007 was conducted in order to (1) better understand the relationship between AFP parameters and convective weather characteristics, and (2) assess the potential use of an objective model for forecasting tactical AFP throughput. An en route airway blockage-based algorithm, using tactical forecast information from the Corridor Integrated Weather System (CIWS), has been developed in order to objectively forecast achievable flow rates through AFP boundaries during convective weather. A description of the model and preliminary model results are presented.

The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance at forecasting route blockage, to assess RAPT operational use during adverse weather, and to evaluate RAPT benefits. The operational test found that RAPT guidance was operationally sound and timely in many circumstances. RAPT applications included increased departure route throughput, more efficient reroute planning, and more timely decision coordination. Estimated annual NY departure delay savings attributed to RAPT in 2007 totaled 2,300 hours, with a cost savings of $7.5 M. The RAPT field study also sought to develop a better understanding of NY traffic flow decision-making during convective weather impacts since the RAPT benefi ts in 2007 were significantly limited by a number of factors other than direct weather impacts. Observations were made of the multi-facility departure management decision chain, the traffic management concerns and responsibilities at specific FAA facilities, and the procedures and pitfalls of the current process for capturing and disseminating key information such as route/fix availability and restrictions.

The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance at forecasting route blockage, to assess RAPT operational use during adverse weather, and to evaluate RAPT benefits. The operational test found that RAPT guidance was operationally sound and timely in many circumstances. RAPT applications included increased departure route throughput, more efficient reroute planning, and more timely decision coordination. Estimated annual NY departure delay savings attributed to RAPT in 2007 totaled 2,300 hours, with a cost savings of $7.5 M. The RAPT field study also sought to develop a better understanding of NY traffic flow decision-making during convective weather impacts since the RAPT benefits in 2007 were significantly limited by a number of factors other than direct weather impacts. Observations were made of the multi-facility departure management decision chain, the traffic management concerns and responsibilities at specific FAA facilities, and the procedures and pitfalls of the current process for capturing and disseminating key information such as route/fix availability and restrictions.

It is generally agreed that effective management of convective weather in congested airspace requires decision support tools that translate the weather products and forecasts into forecasts of ATC impacts and then use those ATC impact forecasts to suggest air traffic management strategies. In future trajectory-based operations, it will be necessary to automatically generate flight trajectories through or around convective weather that pilots will find acceptable. A critical first step, needed in both today's air traffic management environment and in the highly automated systems of the future, is a validated model for airspace that pilots will seek to avoid. At the 12th Conference on Aviation, Range and Aerospace Meteorology (Atlanta, 2006), we reported on an initial Convective Weather Avoidance Model (CWAM1) (DeLaura and Evans; 2006). The CWAM1 outputs are three dimensional deterministic and probabilistic weather avoidance fields (WAFs). CWAM1 used Corridor Integrated Weather System (CIWS) VIL and echo top fields and National Lightning Detection Network (NLDN) data to predict aircraft deviations and penetration. CWAM1 was developed using more than 500 aircraft-convective weather encounters in the Indianapolis Air Route Traffic Control Center (ZID ARTCC) airspace. CWAM1 gave the greatest weight to the difference between flight altitude and the 18 dbZ radar echo top with precipitation intensity playing a secondary role. The deviation prediction error rate in CWAM1 was approximately 25%. This paper presents a new model (CWAM2), based on the analysis of trajectories from several ARTCCs [Indianapolis (ZID), Cleveland (ZOB) and meteorological deviation predictors. Additional weather factors that are considered include vertical storm structure (upper level reflectivity and the height of the VIL centroid derived from the NSSL 3D reflectivity mosaic), vertical and horizontal storm growth, the spatial variation in VIL and echo top fields and storm motion.