The Modernization of Federal Aviation Administration (FAA) Weather Systems—An Update

FAA weather systems will play an important role in the modernization of the National Airspace System (NAS). Weather information services are critical to NAS safety and efficiency. According to the National Research Council (NRC) report on Aviation Weather Services, from 1988 to 1992 one-fourth of all aircraft accidents and one-third of fatal accidents were weather-related. The 1998 Nall Report states that over 86 percent of all weather-related general aviation (GA) accidents resulted in fatalities. The 1999 Aviation Capacity Enhancement Plan reveals that from 1997 to 1998, adverse weather was still a major factor affecting NAS capacity, increasing from 68 percent to 74 percent of system delays greater than 15 minutes. To mitigate these safety and efficiency constraints, aviation weather capabilities in the NAS must undergo major changes.

Another primary goal of the NAS architecture is to incorporate the needs and requirements of NAS users and serve as a 'roadmap' to attaining "Free Flight." Free Flight is the safe and efficient operational capability under instrument flight rules in which pilots have the freedom to select their path and speed in real time. Achieving Free Flight requires the development and dissemination of high quality, short range-predictions of aviation-impacting weather to NAS service providers and users. Consequently, FAA weather systems will be part of an integrated architecture that will ensure all NAS users view the same depiction of hazardous weather; thus "common situational awareness" can be realized which enhances the collaborative decision-making process.

The most dramatic improvement of the NAS Modernization is in the area of weather processors, where two systems, WARP (Weather and Radar Processor) and ITWS (Integrated Terminal Weather System), will function as "weather servers". In the en route domain, WARP will be used by the Air Route Traffic Control Center Center Weather Service Unit meteorologist, while in the terminal domain, ITWS serves non-meteorologist users (e.g., traffic managers and controllers). As weather servers, WARP and ITWS will acquire and process data from sensors (such as NEXRAD, TDWR (Terminal Doppler Weather Radar), and ASOS); 'ingest' computer forecast model output and additional products from the NWS, and receive other weather products (satellite data, aircraft observation data, etc.). These "servers" will then generate tailored weather products for NAS users and alert controllers/meteorologists to the potential for adverse weather. WARP will also produce NEXRAD mosaics for display to the en route controllers, significantly improving the quality of weather advisory support. ITWS will enable terminal controllers to more effectively sequence aircraft.

Both systems will also forward aviation forecasts in a gridded form for processing by NAS automation systems in their respective domains. By incorporating algorithms funded through FAA's Aviation Weather Research program, WARP and ITWS will continue evolving in order to generate more frequent and accurate products, thereby further mitigating the impact of adverse weather on the NAS. Additionally, they will utilize NAS communications infrastructure improvements to ensure near-simultaneous dissemination of aviation-impacting weather throughout the NAS, enhancing common situational awareness. This facilitates collaborative decision-making for traffic flow managers, controllers, flight service specialists, and pilots.