Development of Benefits-Driven Convective Weather Decision Support Systems for Improving Safety and Efficiency in the ATC System through 30 Years of Continuous Use of Real-Time Functional Prototypes

The July 2018 Aeromexico accident flight at Durango Mexico, and the many flight delays/cancellations along the east coast in 2018, serve as a reminder that convective weather continues to be a major safety and efficiency challenge for the aviation system. A key need continues to be decision support to help manage the traffic congestion that arises from the loss of airspace and airport capacity at the same time as facilitating separation of aircraft from weather.

This paper will describe a 30 year program of providing convective weather decision support products in real time to major air traffic control (ATC) facilities, airlines, and pilots. This was achieved with MIT Lincoln Laboratory-developed prototypes as a part of an iterative, benefits-driven system development process illustrated in Figure 1. The full paper will showcase how this process has been applied to the development and refinement of a range of prototype aviation weather systems to the FAA and other stakeholders that deliver significant safety and efficiency benefits.

A combination of operational data, visits to field sites during convective events and operational user feedback were used to determine the current system effectiveness for safety and efficiency. The data-confirmed operational problems were used to develop additional decision support requirements such as improvements to existing products, new products, display changes, training regimes, and/or operational procedure changes. The operational outcomes of decisions made (e.g.. time to reopen a closed route after convective impacts ended) were measured to see if the expected operational benefits were achieved. If not, further iterations of the process shown in Figure 1 were accomplished.

The application of this prototype-driven iterative process at MIT Lincoln Laboratory started with the Terminal Doppler Weather Radar (TDWR) real-time demonstration at Denver in 1988 where fully automated timely warnings of hazardous microburst wind shear (derived from a functional prototype TDWR) were provided to controllers and pilots at Stapleton airport with a TDWR prototype. Subsequent TDWR prototype usage in Kansas City and Orlando identified a number of enhancements for effective low altitude wind shear decision support that are still in use today. Interactions with the Orlando ATC personnel identified an urgent need for improved air traffic management (ATM) decision support to assist in the operational usage of airspace and airports as convective weather impacts changed with time. Addressing these needs necessitated integrating a number of different radars (e.g., ASR9, TDWR, and NEXRAD) as well as other observation systems in the Integrated Terminal Weather System (ITWS). The ITWS prototype provided real time products in Dallas, Memphis, Orlando, and New York. The extreme airspace congestion in the Northeast, coupled with convective weather, identified the need for en route decision support in the form of a Corridor Integrated Weather System (CIWS) which is now providing real time decision support including 0-2 hour rapidly updated forecasts to all of the major US ATC facilities in the lower 48 states via the Traffic Flow Management System (TFMS). Another key issue for timely decision making identified in the New York operational usage was the challenge of communications and coordination illustrated in Figure 2.

Due to the many ATC (and airline) facilities which interact in coping with the combination of convective weather impacts and congestion in much of the US air system, the observation process associated with CIWS system design necessitated simultaneous observations at a number of different ATC facilities to better understand the decision support needed to provide measureable operational benefits. To the best of our knowledge, such large scale, multi-stakeholder benefits-driven observations as a part of a decision support design process had not been accomplished previously.

Managing the combination of convective weather and airspace congestion necessitates selectively holding traffic at the origin airport to insure that a manageable traffic volume enters convective impacted airspace. This need to dynamically, proactively constrain traffic led to the development of 2-8 hour convective forecasts that integrated the radar based 0-2 hour forecasts with High Resolution Rapid Refresh (HRRR) forecasts. These forecasts have been refined through real-time operational usage and post event analysis with a Consolidated Storm Prediction for Aviation (CoSPA) prototype.

The ITWS and CoSPA forecasts have been used in prototype integrated ATM-weather integrated systems which translate the convective weather forecasts into explicit forecasts of airspace availability (e.g., routes and flows through regions of en route airspace).

The prototypes have provided the technical exhibits and operational usage concepts for a number of procured FAA aviation weather decision support systems (e.g., TDWR, ITWS and the Route Availability Planning Tool (RAPT)), providing technology for the NextGen Weather Processor (NWP) which is currently in full-scale development by the FAA.

Major operational benefits in terms of safety and efficiency have been achieved with the operational decision support systems whose design evolved out of the prototype usage and by the currently operating prototypes. There have been no air carrier low altitude wind shear accidents at TDWR equipped airports. The delay reductions arising from ITWS and CIWS alone currently are estimated to be well in excess of $300 M per year.

DISTRIBUTION STATEMENT A. Approved for public release. Distribution is unlimited.

This material is based upon work supported by the Federal Aviation Administration under Air Force Contract No. FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Federal Aviation Administration.

References

Davison, H. and Hansman, R. J., 2001, “Identification of Inter-Facility Communication and Coordination Issues in the U.S. Air Traffic Control System,” MIT International Center for Air Transportation paper ICAT 2001-11-21

Hayley Reynolds, Kiran Lokhande, Maria Kuffner and Sarah Yenson “Human-Systems Integration and Air Traffic Control” Lincoln Laboratory Journal vol. 19, number 1, 2012.