Delay Reduction at Newark International Airport using Terminal Weather Information Systems

Aircraft delays at Newark, NJ (EWR) have been consistently at or near the top of the list among all airports in the United States. The New York Integrated Terminal Weather System (ITWS) demonstration system began operations in the Fall of 1998 to help reduce delays and increase safety in the extremely busy and complex airspace within, and surrounding, the New York Terminal Radar Approach Control Area (TRACON). In addition, the Terminal Convective Weather Forecast product (TCWF) was introduced into the New York TRACON in the fall of 1999 to provide up to a one-hour forecast of the motion of significant weather. The use of ITWS/TCWF by air traffic personnel has led to substantial benefits, through reductions in delay and holding, as well as better planning and avoidance of deviations. For example, on 24 May 1999, TRACON personnel used ITWS to plan over 100 necessary deviations, while releasing 50 extra planes over 10 hours, and landing planes right up until airport closure, significantly reducing unnecessary holding. The ITWS Terminal Winds product has also been shown to considerably reduce holding, by as much as 100 aircraft per day, during strong vertical wind shear events on both stormy and clear days.

Over the year of the study, three main types of weather were found to lead to high delays at Newark. These were, in order of frequency: low ceilings and visibility (C&V), thunderstorms, and strong gusty surface and low-level winds; in order of severity (for a single day): thunderstorms, low C&V, and winds. While thunderstorms have the most severe impact per event (a 4:3:2 delay ratio among the three events), the annual delay impact of C&V is actually greater (by a small margin) due to their higher frequency. Furthermore, the impact of reduced capacity due to low ceilings and visibility were generally more predictable. High surface winds had the potential for delays depending on runway configuration (and hence the direction of the wind).

When studying delays and delay reduction, it is critical to understand what delays are avoidable versus those that are unavoidable. The initial goal of this study was to quantify what types of weather delays at Newark could be mitigated by ITWS/TCWF. Given that C&V had the greatest overall impact, we focused our study on these cases to determine if available capacity was being efficiently utilized. While several cases showed that traffic management did well matching demand to available capacity, there were cases which showed room for at least some improvement. Through the use of an established model for aircraft queuing, it is shown that even a small improvement could result in significant cost benefits.

Improvement in this area will require highly accurate one-hour forecasts for use in traffic flow management decision making. Several research efforts are ongoing to improve the forecasts and the traffic flow managers and airline dispatchers access to these forecasts. One effort is the aforementioned TCWF, which has been shown in many cases to accurately predict the start and end to stratiform precipitation events. Another effort is underway to more accurately predict all low ceiling and visibility events, including those caused by fog and low clouds not associated with precipitation.