Patterns of One-minute Demands vs . One-minute Peak Demand for Alerting Sectors

The Federal Aviation Administration (FAA) Traffic Flow Management System (TFMS) currently declares an alert for any 15-minute interval in which the predicted demand exceeds the Monitor/Alert Parameter (MAP) for any airport, sector, or fix. For airports and fixes traffic demand is measured by aggregate 15-minute counts. For a sector, however, TFMS predicts the demand for each minute, and then uses the demand of the peak minute in a 15-minute interval to decide whether to declare an alert for the entire 15-minute interval. Using the peak demand from a single minute to declare alerts has been criticized by TFM specialists for three reasons. First, the demand from a single minute does not accurately reflect the workload for the entire 15-minute interval. Second, using demand for a single minute leads to instability; that is, slight fluctuations in demand from minute to minute can lead to alerts flickering on and off. Third, the interval that is alerted depends on arbitrary 15-minute boundaries. To deal with these problems with the current method of declaring alerts, we propose a new method of declaring sector alerts that is based on the patterns of one-minute demands and that matches more closely the intuition of traffic managers about what more likely represents a potential problem. Introduction This paper presents the latest results of research conducted at the Volpe Center supported by the FAA on enhancing the Traffic Flow Management System (TFMS) Monitor/Alert function for identifying potential congestion at National Airspace System (NAS). This research contributes to the FAA’s effort to improve aviation safety and efficiency of utilizing the NAS operational resources while accommodating increased air traffic demand, which are among the major goals of the Next Generation Air Transportation program (NextGen) [1]. One of the means to increase aviation safety is improvement of strategic air Traffic Flow Management decision making, which requires more accurate and reliable predictions of congestion in the NAS. Exploring new methods for improving TFM decision making is an important research component to support NextGen goals. TFMS predicts the volume of air traffic for airports, sectors, and fixes to identify potential congestion problems. TFMS’s Monitor/Alert functionality compares predicted traffic demand with available capacity or Monitor/Alert Parameter (MAP) and issues alerts wherever and whenever demand threatens to exceed capacity. This helps TFM specialists in their strategic decision-making for resolving congestion problems. Although the general alerting rule is the same for airports, fixes and en route sectors and is based on comparison of predicted demand with available capacity, the TFMS defines traffic demand for sectors differently than for airports and fixes. Traffic demand for airports and fixes is measured by aggregate number of flight counts per 15-minute interval, e.g., number of arrivals or departures at an airport per 15minute or number of flights crossing a fix per 15-minute. Those aggregate 15-minute demand counts are used in determining airport or fix alert status. For sectors, TFMS uses a different approach to determining sector demand and sector alert status.