Publications

Refine Results

(Filters Applied) Clear All

Operational usage of the Route Availability Planning Tool during the 2007 convective weather season : executive summary

Published in:
MIT Lincoln Laboratory Report ATC-339-1

Summary

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.
READ LESS

Summary

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...

READ MORE

Operational usage of the Route Availability Planning Tool during the 2007 convective weather season

Published in:
MIT Lincoln Laboratory Report ATC-339

Summary

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.
READ LESS

Summary

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...

READ MORE

Modeling convective weather avoidance in enroute airspace

Published in:
13th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 20-24 January 2008.

Summary

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.
READ LESS

Summary

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...

READ MORE

Evaluation of weather impact models in departure management decision support: operational performance of the Route Availability Planning Tool (RAPT) prototype

Published in:
13th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 20-24 January 2008.

Summary

In this paper, the revised RAPT algorithm and display are described and evaluated. The fidelity of the RAPT operational model is assessed by comparing RAPT departure status with observed departure flows (i.e., trajectories, weather avoidance maneuvers and storm penetrations) on several days when convective weather SWAPs were in effect in New York. Real-time in-situ observations at RAPT facilities (described in a companion paper at this conference; Robinson, 2008), user feedback from RAPT playbacks and the REPEAT web site are used to support this post-event evaluation. For example, real time observations provide the time and operational rationale for a specific departure route closure identified in the traffic flow analysis. This information is necessary to identify closures or flow restrictions that are the result of factors outside of the current RAPT algorithm domain (e.g., traffic restrictions due to volume, downstream congestion, etc.). Real time observations are also used to identify specific times when critical, weather-related operational decisions were made. The RAPT guidance at these critical decision points is analyzed to determine if RAPT provided information that enabled (or could have enabled, had it been used) more timely or effective decisions. The effect of forecast uncertainty on RAPT performance is also examined, particularly in convective weather situations where the location, severity and operational impact were difficult to predict. Strategies that mitigated risks associated with forecast uncertainty are presented. These include the use of additional information provided in the RAPT display, such as echo top heights encountered along the departure route, to confirm or modify RAPT guidance and the consideration of the departure status of two or more adjacent routes to 'average out' variations in the departure status timelines.
READ LESS

Summary

In this paper, the revised RAPT algorithm and display are described and evaluated. The fidelity of the RAPT operational model is assessed by comparing RAPT departure status with observed departure flows (i.e., trajectories, weather avoidance maneuvers and storm penetrations) on several days when convective weather SWAPs were in effect in...

READ MORE

Key research issues for near term operational use of integrated convective weather-ATM decision support systems

Author:
Published in:
13th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 20-24 January 2008.

Summary

Thunderstorm-related delays dominate the overall U.S. airspace delay statistics and continue to increase, even though a number of new weather information systems and air traffic management (ATM) decision support tools have been deployed since 1999. Operational decision makers must mitigate the network congestion that arises from rapidly varying capacity loss in both en route and terminal airspace. Improving decision making in such an environment requires explicitly considering airspace structure, network impacts, forecast uncertainty and pilot preferences for weather avoidance. To date, the NextGen initiative has focused on envisioning an operational concept and research agenda for 2025 where it is assumed that aircraft separation and weather avoidance is accomplished using a high degree of automation. In this paper, we consider research to achieve significant improvements in the near term (2010-2015) where aircraft separation is provided largely by controllers and hazardous weather avoidance is accomplished by pilots using visual cues, reports from other aircraft, on board weather radar and ATC advisories. We briefly review the current status of work in key areas and then suggest major near term initiatives. Key elements of the research program to be discussed include: 1. Translation of convective weather products into ATC impacts (including handling of uncertainty in the convective weather forecasts). Initial models for en route pilot avoidance of storms and sector capacity in convective weather have shown promising results, but clearly much more research is needed in this area. 2. Determining when and where available capacity was not appropriately utilized during convective events, based on both facility observations during storm events and computations of avoidable delay. Preliminary results suggest that much of today's delay is in fact avoidable. 3. Developing integrated weather-ATM decision support tools (DST) to enable decision makers to more fully utilize available capacity. The accuracy of contemporary convective weather forecasts is a key issue in the design of such systems. Initial operational experience with a departure decision support tool will be discussed to illustrate key points. 4. Explicitly considering the human side of convective weather ATM [e.g., how individuals make real time decisions in collaboration with other decision makers (e.g., ATC, airlines, dispatch, pilots)]. Recent results from field usage of convective weather decision support tools will be interpreted in the context of recent literature on how people actually make decisions and perform cognitively complex functions in demanding situations.
READ LESS

Summary

Thunderstorm-related delays dominate the overall U.S. airspace delay statistics and continue to increase, even though a number of new weather information systems and air traffic management (ATM) decision support tools have been deployed since 1999. Operational decision makers must mitigate the network congestion that arises from rapidly varying capacity loss...

READ MORE

Air traffic management decision support during convective weather

Published in:
Lincoln Laboratory Journal, Vol. 16, No. 2, June 2007, pp. 263-276.

Summary

Flight delays caused by thunderstorms are a significant and growing problem for airlines and the flying public. Thunderstorms disrupt the structured, preplanned flight routing and control process that is used to handle dense air traffic streams in congested airspace. Today's coping strategies are developed by traffic flow management (TFM) specialists who interpret weather measurements and forecasts to develop delay and rerouting strategies. The effectiveness of these strategies is limited by the lack of quantitative models for the capacity impacts of thunderstorms, and by the difficulty of developing and executing timely response strategies during rapidly changing convective weather. In this article, we describe initial work to develop more effective response strategies. We first review insights gained during operational testing of a simple but highly effective Route Availability Planning Tool that can significantly reduce convective-weather induced departure delays at congested airports. We then discuss work to develop core technical capabilities and applications that address broader TFM problems, including en route congestion. Objective models for airspace capacity reductions caused by thunderstorms are discussed, as is an associated scheduling algorithm that exploits the capacity estimates to develop broad-area TFM strategies that minimize delay. We conclude by discussing candidate real-time applications and airspace system performance analysis that is enabled by our weather-capacity models and optimal scheduling algorithm.
READ LESS

Summary

Flight delays caused by thunderstorms are a significant and growing problem for airlines and the flying public. Thunderstorms disrupt the structured, preplanned flight routing and control process that is used to handle dense air traffic streams in congested airspace. Today's coping strategies are developed by traffic flow management (TFM) specialists...

READ MORE

Improving air traffic management group decision-making during severe convective weather

Published in:
11th World Conf. on Transport Research, June 2007.

Summary

There is an urgent need to enhance the efficiency of United States (U.S.) air traffic management (ATM) decision-making when convective weather occurs. Thunderstorm ATM decisions must be made under considerable time pressure with inadequate information (e.g., missing or ambiguous), high stakes, and poorly defined procedures. Often, multiple decisions are considered simultaneously; each requiring coordination amongst a heterogeneous set of decision-makers. Recent operational experience in the use of improved convective weather decision support systems in the Northeast quadrant of the U.S. is reviewed in the context of literature on individual and team decision-making in complex environments. Promising areas of research are identified.
READ LESS

Summary

There is an urgent need to enhance the efficiency of United States (U.S.) air traffic management (ATM) decision-making when convective weather occurs. Thunderstorm ATM decisions must be made under considerable time pressure with inadequate information (e.g., missing or ambiguous), high stakes, and poorly defined procedures. Often, multiple decisions are considered...

READ MORE

Implications of a successful benefits demonstration for integrated weather/air traffic management (WX/ATM) system development and testing

Author:
Published in:
12th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 29 January- 2 February 2006.

Summary

One of the major challenges in the US National Airspace System (NAS) today is improving the decisions made when adverse aviation weather occurs. Major increases in the usage of high altitude en route airspace by regional and corporate jets, coupled with greater use of "secondary" airports by low cost air carriers, have dramatically increased the complexity of operating the NAS during bad weather. One potentially powerful approach to improving decision making is to explicitly combine aviation weather information with aviation system information to create an integrated weather/air traffic management (wx/ATM) system that improves the productivity of the NAS operators. However, it will not be enough to be able to develop the technology that could make system improvements possible; it has now become increasingly important to demonstrate quantitative user benefits for any new initiatives. In this paper, we discuss the implications on the development and testing of wx/ATM systems of the need for a successful operational benefits demonstration of the new capability. The paper proceeds as follows. In the next section, we discuss how an integrated wx/ATM system differs from the "conventional" aviation weather decision process. Section 3 describes current efforts by the FAA and the Office of Management and Budget (OMB) to appropriately consider operational benefits as a factor in investment decision making. Section 4 discusses key elements of an "operational benefits centric" approach to wx/ATM system development and testing. Sections 5 and 6 discuss two contemporary examples of integrated wx/ATM systems in the context of section 4. The paper concludes with a summary and recommendations.
READ LESS

Summary

One of the major challenges in the US National Airspace System (NAS) today is improving the decisions made when adverse aviation weather occurs. Major increases in the usage of high altitude en route airspace by regional and corporate jets, coupled with greater use of "secondary" airports by low cost air...

READ MORE

Quantifying delay reduction benefits for aviation convective weather decision support systems

Published in:
11th Conf. on Aviation, Range and Aerospace Meteorology, 4-8 October 2004.

Summary

In this paper, we summarize contemporary approaches to quantifying convective weather delay reduction benefits. We outline a program to develop a significantly improved capability that can be used to assess benefits of specific systems. This program may potentially accomplish weather impact normalization for studies of National Airspace System (NAS) performance in handling convective weather. Benefits quantification and NAS performance assessment have become very important topics for the aviation weather community. In an era of significant federal government and airline budget austerity for civil aviation investments, it is essential to quantitatively demonstrate delay reduction benefits of improved weather decision support systems. Major FAA initiatives stress the importance of quantitative system performance metrics that are related to aviation weather. For example, the new FAA Air Traffic Organization (ATO) and the FAA Flight Plan 2004-08 both have quantitative performance metrics that are closely related to reducing convective weather delays. The Flight Plan metrics include: "Improving the percentage of all flights arriving within 15 minutes of schedule at the 35 OEP airports by 7%, as measured from the FY2000-02 baseline, through FY08," and "Maintaining average en route travel times among the eight major metropolitan areas." The ATO metrics include the percentage of on time gate arrivals and the fraction of departures that are delayed greater than 40 minutes. However, these metrics currently do not account for the differences in convective weather severity and changes in the NAS. The dramatic increase in convective season delays in 2004 (Figure 1) due to a combination of severe weather, increases in overall demand, and specific airport issues has demonstrated that one needs to consider these other factors. Approaches to delay reduction quantification that were viewed as successful and valid several years ago are no longer considered to be adequate by either by the FAA investment analysis branch or by the Office of Management and Budget (OMB). The paper proceeds as follows. We first discuss at some length the mechanisms by which convective weather delay occurs in the NAS and highlight challenges in delay reduction assessment. We consider this to be very important since one needs to understand how the system operates if one is to design an effective, accurate performance assessment system. We then consider benefits quantification based on feedback from experienced users of a system. Feedback on "average" benefits from a system at the end of a test period was used to generate delay reduction estimates for the Integrated Terminal Weather System (ITWS) and the Weather and Radar Processor (WARP). This end-of-season interview approach was not viable in highly congested en route airspace. Hence, a new approach was developed for Corridor Integrated Weather System (CIWS) benefits assessment that uses real time observations of product usage during convective weather events coupled with in depth analysis of specific cases. Next, we discuss the problems that arise when one attempts to quantify delay reduction benefits by comparing flight delays before and after the Integrated Terminal Weather System (ITWS) system was deployed at Atlanta Hartsfield International Airport (ATL). This seemingly simple approach has proven very difficult in practice because the convective weather events in the different time periods are virtually never identical and because other aspects of the NAS may also have changed (e.g., user demand, fleet mix, and other systems that impact convective weather delays). It has become clear that one needs a quantitative model for the NAS that would permit adjustment of measured delay data to account at least for the differences in convective weather and changes in user demand (i.e., flight scheduling). The paper concludes with recommendations for measuring near term benefits of various classes of convective weather decision support systems.
READ LESS

Summary

In this paper, we summarize contemporary approaches to quantifying convective weather delay reduction benefits. We outline a program to develop a significantly improved capability that can be used to assess benefits of specific systems. This program may potentially accomplish weather impact normalization for studies of National Airspace System (NAS) performance...

READ MORE

Route selection decision support in convective weather: a case study of the effects of weather and operational assumptions on departure throughput

Published in:
5th Eurocontrol/FAA ATM R&D Seminar, 23-27 2003.

Summary

This paper presents a detailed study of a convective weather event affecting the northeastern United States on 19 April 2002: its impacts on departure throughput, the response of traffic managers and an analysis of the potential effects of decision support on system performance. We compare actual departure throughput to what may have been achieved using the Route Availability Planning Tool (RAPT), a prototype decision support tool. We examine two questions: Can decision support identify opportunities to release departures that were missed during the event? How is route selection guidance affected by the operational model incorporated into the decision support tool? By "operational model", we mean three things: the choice of weather forecast information used to define hazards (precipitation, echo tops, etc.), the model for how airspace is used (route definition and allocation) and the assessment of the likelihood that a given route is passable. We focus our analysis on the operational model only; we eliminate weather forecast uncertainty as a factor in the analysis by running RAPT using the actual observed weather as the forecast ('perfect' forecast). Results show that decision support based on perfect forecasts is sensitive to all three elements of the operational model. The sensitivity to weather metrics became evident when we compared decision support based upon perfect forecasts of level 3 vertically integrated liquid (VIL) to that based upon VIL plus storm echo tops. Traffic managers were at times able to move more aircraft by abandoning nominal routing than if they had used nominal routing with perfect weather information. The assessment of route availability will, at times, be ambiguous; different interpretations of that assessment lead to decisions that result in significant differences in departure throughput. These results suggest that for traffic flow management tools, a realistic operational model may be at least as important as the frequently discussed problem of weather forecast uncertainty.
READ LESS

Summary

This paper presents a detailed study of a convective weather event affecting the northeastern United States on 19 April 2002: its impacts on departure throughput, the response of traffic managers and an analysis of the potential effects of decision support on system performance. We compare actual departure throughput to what...

READ MORE