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Sector workload model for benefits analysis and convective weather capacity prediction
June 10, 2013
Conference Paper
Published in:
10th USA/Europe Air Traffic Management Research and Development Sem., ATM 2013, 10-13 June 2013.
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Summary
En route sector capacity is determined mainly by controller workload. The operational capacity model used by the Federal Aviation Administration (FAA) provides traffic alert thresholds based entirely on hand-off workload. Its estimates are accurate for most sectors. However, it tends to over-estimate capacity in both small and large sectors because it does not account for conflicts and recurring tasks. Because of those omissions it cannot be used for accurate benefits analysis of workload-reduction initiatives, nor can it be extended to estimate capacity when hazardous weather increases the intensity of all workload types. We have previously reported on an improved model that accounts for all workload types and can be extended to handle hazardous weather. In this paper we present the results of a recent regression of that model using an extensive database of peak traffic counts for all United States en route sectors. The resulting fit quality confirms the workload basis of en route capacity. Because the model has excess degrees of freedom, the regression process returns multiple parameter combinations with nearly identical sector capacities. We analyze the impact of this ambiguity when using the model to quantify the benefits of workload reduction proposals. We also describe recent modifications to the weather-impacted version of the model to provide a more stable normalized capacity measure. We conclude with an illustration of its potential application to operational sector capacity forecasts in hazardous weather.
Summary
En route sector capacity is determined mainly by controller workload. The operational capacity model used by the Federal Aviation Administration (FAA) provides traffic alert thresholds based entirely on hand-off workload. Its estimates are accurate for most sectors. However, it tends to over-estimate capacity in both small and large sectors because...
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Multifunction Phased Array Radar wind shear experiment
November 5, 2012
Conference Paper
Published in:
26th Conf. on Sever Local Storms, 5-8 November 2012.
Summary
Terminal Doppler Weather Radars (TDWRs) provide near-ground wind shear detection that is critical for aircraft safety at 46 airports across the United States. These systems are part of the larger network of 510 weather and aircraft surveillance radars owned and operated by government agencies in the continental United States. As the TDWR and other radar systems approach their engineering design life cycles, the Federal Aviation Administration (FAA), National Weather Service (NWS), and Department of Defense (DoD) are considering potential replacement systems (OFCM 2006; Weber et al. 2007). One option under consideration that would maintain the current airspace coverage is a replacement network of 334 Multifunction Phased Array Radars (MPARs) (Weber et al. 2007). The MPAR network described by Weber et al. (2007) would include two classes of systems: A high-resolution, full-scale version with an 8-m diameter antenna, and a lower-resolution terminal version with a 4-m diameter antenna, termed Terminal MPAR, or TMPAR. As the proposed TMPAR design has lower azimuthal beam resolution and less sensitivity than TDWRs, it is crucial to determine the impacts of that design on the detection of low-altitude wind shear. The design of the SPY-1A PAR, a research radar at the National Weather Radar Test Bed in Norman, Oklahoma (Zrnić et al. 2007), makes it a good proxy for examining the potential wind shear detection performance of the TMPAR. Therefore, in spring 2012, the National Oceanic and Atmospheric Administration (NOAA) National Severe Storms Laboratory organized and executed the MPAR Wind Shear Experiment (WSE) in collaboration with the FAA, NOAA's NWS Radar Operations Center, the University of Oklahoma Advanced Radar Research Center (OU ARRC), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). The primary objective of the MPAR WSE was to collect low-altitude observations with the SPY-1A PAR (hereafter, PAR) for comparison with observations from the nearby Oklahoma City (OKC) TDWR. Of particular interest is comparison of MIT LL wind shear detection algorithm performance using data from these two radars; this analysis is reported in Cho et al. (2013). Data were also collected from other radars in central Oklahoma to facilitate basic research on microbursts and other wind-producing storms. This paper provides an overview of the MPAR WSE and observed wind shear events.
Summary
Terminal Doppler Weather Radars (TDWRs) provide near-ground wind shear detection that is critical for aircraft safety at 46 airports across the United States. These systems are part of the larger network of 510 weather and aircraft surveillance radars owned and operated by government agencies in the continental United States. As...
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Air traffic decision analysis during convective weather events in arrival airspace
September 17, 2012
Conference Paper
Published in:
12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conf. and 14th AIAA/ISSM, 17-19 September 2012.
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Decision making during convective weather events in the terminal area is shared among pilots and air traffic management, where uninformed decisions can result in wide-spread cascading delays with high-level impacts. Future traffic management systems capable of predicting terminal impacts will mitigate these unnecessary delays; however in order to realize this vision, it is important to understand the decision mechanisms behind convective weather avoidance. This paper utilizes an arrival adaptation of the Convective Weather Avoidance Model (CWAM) to investigate the catalysts for arrival traffic management decision making. The analysis is broken down by category of terminal airspace structure in addition to the type of decision. The results show that pilot behavior in convective weather is heavily dependent on the terminal airspace structure. In addition, pilot and air traffic management decisions in convective weather can be discriminated with large-scale weather features.
Summary
Decision making during convective weather events in the terminal area is shared among pilots and air traffic management, where uninformed decisions can result in wide-spread cascading delays with high-level impacts. Future traffic management systems capable of predicting terminal impacts will mitigate these unnecessary delays; however in order to realize this...
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Evaluation of the Convective Weather Avoidance Model for arrival traffic
September 17, 2012
Conference Paper
Published in:
12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conf. and 14th AIAA/ISSM, 17-19 September 2012.
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Summary
The effective management of traffic flows during convective weather events in congested air space requires decision support tools that can translate weather information into anticipated air traffic operational impact. In recent years, MIT Lincoln Laboratory has been maturing the Convective Weather Avoidance Model (CWAM) to correlate pilot behavior in the enroute airspace with observable weather parameters from convective weather forecast systems. This paper evaluates the adaptation of the CWAM to terminal airspace with a focus on arrival decision making. The model is trained on data from five days of terminal convective weather impacts. The performance of the model is evaluated on an independent dataset consisting of six days of convective weather over a variety of terminal areas. Model performance in different terminal areas is discussed and the sensitivity of prediction accuracy to weather forecast horizon is presented.
Summary
The effective management of traffic flows during convective weather events in congested air space requires decision support tools that can translate weather information into anticipated air traffic operational impact. In recent years, MIT Lincoln Laboratory has been maturing the Convective Weather Avoidance Model (CWAM) to correlate pilot behavior in the...
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Data-driven evaluation of a flight re-route air traffic management decision-support tool
July 21, 2012
Conference Paper
Published in:
Applied Human Factors and Ergonomics Conf., 21 July 2012.
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Summary
Air traffic delays in the U.S. are problematic and often attributable to convective (thunderstorms) weather. Air traffic management is complex, dynamic, and influenced by many factors such as projected high volume of departures and uncertain forecast convective weather at airports and in the airspace. To support the complexities of making a re-route decision, which is one solution to mitigate airspace congestion, a display integrating convective weather information with departure demand predictions was prototyped jointly by MIT Lincoln Laboratory and the MITRE Corporation. The tool was deployed to twelve air traffic facilities involved in handling New York area flights for operational evaluation during the summer of 2011. Field observations, data mining and analyses were conducted under both fair and convective weather conditions. The system performance metrics chosen to evaluate the tool's effectiveness in supporting re-route decisions include predicted wheels-off error, predicted wheels-off forecast spread, and hourly departure fix demand forecast spread. The wheels-off prediction errors were near zero for half the flights across all days, but the highest 10% errors exceeded 30 minutes on convective weather days. The wheels-off forecast spread exceeded 30 minutes for 25% of forecasts on convective weather days. The hourly departure demand forecast spread was 9 flights or less for 50% of departures across all days except one. Six out of the seven days having the highest hourly departure demand forecast spreads occurred in the presence of long-lived weather impacts.
Summary
Air traffic delays in the U.S. are problematic and often attributable to convective (thunderstorms) weather. Air traffic management is complex, dynamic, and influenced by many factors such as projected high volume of departures and uncertain forecast convective weather at airports and in the airspace. To support the complexities of making...
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Establishing wind information needs for four dimensional trajectory-based operations
June 26, 2012
Conference Paper
Published in:
1st Int. Conf. on Interdisciplinary Science for Innovative Air Traffic Management, ISIATM, 26 June 2012.
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Accurate wind information is of fundamental importance to the delivery of benefits from future air traffic concepts. A Wind Information Analysis Framework is described in this paper and its utility for assessing wind information needs for a four-dimensional trajectory based operations application is demonstrated.
Summary
Accurate wind information is of fundamental importance to the delivery of benefits from future air traffic concepts. A Wind Information Analysis Framework is described in this paper and its utility for assessing wind information needs for a four-dimensional trajectory based operations application is demonstrated.
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Towards the detection of aircraft icing conditions using operational dual-polarimetric radar
June 25, 2012
Conference Paper
Published in:
7th European Conf. on Radar in Meteorology and Hydrology, ERAD, 25-29 June 2012.
Summary
In anticipation of the dual-polarimetric upgrade to the National Weather Service operational radar network (WSR-88D) research is being conducted to utilize this extensive new data source for remote aircraft icing detection. The first challenge is to accurately locate the melting layer. A new image-processing-based algorithm is proposed and demonstrated. The next challenge is to use the dual-polarimetric data above the melting level to distinguish regions containing super-cooled liquid water, which constitutes an aviation icing hazard, from regions of pure ice and snow. It has been well documented that the S-band dual-polarimetric radar signatures at individual range gates of super-cooled liquid water and ice crystals overlap significantly, complicating the identification of icing conditions using individual radar measurements. Recently several investigators have found that the aggregate characteristics of dual-polarimetric radar measurements over regions on the order of several kilometers show distinguishing features between regions containing super-cooled liquid and those with ice only. In this study, the features found in the literature are evaluated, extended and combined using a fuzzy-logic framework to provide an icing threat likelihood. The results of this new algorithm are computed using data collected in Colorado from the Colorado State University CHILL radar and the National Center for Atmospheric Research S-Pol radar (collectively called FRONT – The Front Range Observational Testbed) collected in the winter of 2010/2011 in coordination with the NASA Icing Remote Sensing System (NIRSS) and compared to pilot reports on approach or departure from nearby airports. The preliminary results look encouraging and will be presented. The ultimate goal is to produce an end-to-end algorithm to produce a reliable icing threat product that can then be combined with existing icing detection systems to improve their performance.
Summary
In anticipation of the dual-polarimetric upgrade to the National Weather Service operational radar network (WSR-88D) research is being conducted to utilize this extensive new data source for remote aircraft icing detection. The first challenge is to accurately locate the melting layer. A new image-processing-based algorithm is proposed and demonstrated. The...
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Estimation of New York departure fix capacities in fair and convective weather
January 23, 2012
Conference Paper
Published in:
3rd Aviation, Range, and Aerospace Meteorology, 23 January 2012.
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When convective weather impacts the New York Metro airspace, traffic managers may employ several tactics to mitigate weather impacts and maintain manageable and efficient flow of traffic to and from the airports. These tactics, which include maneuvering individual flights through weather, merging and redirecting traffic flows to avoid storms, and rerouting traffic from blocked routes onto unimpacted or less-impacted routes, all affect the capacity of the affected airspace resources (departure fixes, routes, or gates). Furthermore, the location of the weather impacts can have a great influence on the amount of leeway that traffic managers have in applying these tactics. In New York, departure fixes, the gateways to en route airspace where departure traffic from several metroplex airports are merged onto en route airways, are particularly critical. When congestion (volume of traffic in excess of capacity) occurs near departure fixes as a result of weather impacts, traffic managers must resort to airborne holding or unplanned departure stops to quickly reduce traffic over the fix to manageable levels. Nonetheless, when convective weather impacts densely packed and busy metroplex airspaces, it is inevitable that traffic will need to use impacted departure fixes and routes to keep delays in check. For this reason, predictions of the weather-impacted capacity of critical airspace resources like departure fixes that are based in the reality of commonly used impact mitigation tactics, are needed to help traffic managers anticipate and avoid disruptive congestion at weather-impacted departure fixes. The Route Availability Planning Tool (RAPT) is a departure management decision support tool that has been used in the New York operations since 2003. It predicts the weather impact on departure fixes and routes based on departure times. RAPT assigns a departure status (RED, YELLOW, or GREEN) to individual departure routes based on the departure time, the predicted severity of the convective weather that will impact the route, the likelihood that a pilot will deviate to avoid the weather along the route, and the operational sensitivity to deviations in the departure airspace that the route traverses. These blockages assist traffic managers in prompt route reopening of routes closed by convective weather impacts, as well as providing situational awareness for impeding impacts on routes. RAPT also identifies the location of weather impacts along the departure route. This paper presents an analysis of observed fair weather and convective weather impacted throughput on New York departure fixes. RAPT departure status and impact location are used to characterize the severity of departure fix weather impacts, and weather-impacted fix capacity ranges are estimated as a function of RAPT impacts. The use of traffic flow merging is identified, and weather impacted capacity ranges for commonly used merged flows are also estimated.
Summary
When convective weather impacts the New York Metro airspace, traffic managers may employ several tactics to mitigate weather impacts and maintain manageable and efficient flow of traffic to and from the airports. These tactics, which include maneuvering individual flights through weather, merging and redirecting traffic flows to avoid storms, and...
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Estimating the likelihood of success in departure management strategies during convective weather
October 16, 2011
Conference Paper
Published in:
Proc. 30th IEEE/AIAA Digital Avionics Systems Conference, DASC, 16-20 October 2011, pp. 6D4.
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The presence of convective weather (thunderstorms) in terminal and nearby en route airspace of major metroplex areas can have significant impacts on departure operations. Traffic on departure routes impacted by convective weather may be constrained by miles-in-trail (MIT) restrictions, to allow controllers the time needed to maneuver individual flights around thunderstorms that pilots wish to avoid. When the workload required to manage traffic flows becomes too great, departure routes may be closed. Departures still on the ground that are filed on closed or restricted routes may face significant delays as they wait for clearance on their filed route, or for a viable reroute to be implemented. The solution proposed in concepts such as the Integrated Departure Route Planning tool (IDRP) [1] is the use of weather and departure demand forecasts to plan and implement reroutes to avoid weather and volume congestion proactively, well in advance of route restrictions or closures.
Summary
The presence of convective weather (thunderstorms) in terminal and nearby en route airspace of major metroplex areas can have significant impacts on departure operations. Traffic on departure routes impacted by convective weather may be constrained by miles-in-trail (MIT) restrictions, to allow controllers the time needed to maneuver individual flights around...
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Initial validation of a convective weather avoidance model (CWAM) in departure airspace
October 16, 2011
Conference Paper
Published in:
DASC 2011, 30th IEEE/AIAA Digital Avionics Systems Conference, 16-20 October 2011, pp. 3A2.
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The Convective Weather Avoidance Model (CWAM) translates gridded, deterministic weather observations and forecasts into Weather Avoidance Fields (WAF). The WAF gives the probability, at each point in the grid, that a pilot will choose to deviate around convective weather at that location. CWAM have been developed and validated for en route, high altitude, level flight, low altitude level flight, and for descending arrivals. A heuristic CWAM for departures was also developed and deployed as part of the Route Availability Planning Tool (RAPT) prototype development in New York and Chicago. This paper presents an evaluation of the departure CWAM that is currently deployed as part of RAPT, based on an analysis of departure traffic in the Chicago terminal area during convective weather events.
Summary
The Convective Weather Avoidance Model (CWAM) translates gridded, deterministic weather observations and forecasts into Weather Avoidance Fields (WAF). The WAF gives the probability, at each point in the grid, that a pilot will choose to deviate around convective weather at that location. CWAM have been developed and validated for en...
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