Publications

The Federal Aviation Administration (FAA) is currently embarking on programs, such as the Terminal Doppler Weather Radar (TDWR) and Integrated Terminal Weather Systems (ITWS), that will significanlty improve the aviation weather information in the terminal area. For example, TDWR data will be available at 47 airports across the United States that have high traffic and significant risk of wind shear. The TDWRs automatically report microburst, gust front and precipitaion near the airport to air traffic control personnel on a 24-hour basis. Given the great increase in the quantity and quality of terminal weather information, it is highly desirable to provide this information directly to pilots rather than relying on voice communications. Providing terminal weather information automatically via data link will enhance pilot awareness of weather hazards and lead to more efficient utilization of aircraft. It may also decrease air traffic controller workload and reduce ratio frequency congestion. This report describes work performed in 1995 to provide direct pilot access to terminal weather information via an existing data link known as ACARS (Aircraft, Communication Addressing and Reporting System). More than 4000 aircraft operate in the United States with ACARS equipment. During 1995, five Lincoln-operated testbeds provided near real-time terminal weather information to pilots of AFCARS-equipped aircraft in both text and character graphics formats. This effort follows earlier successful demonstrations during the summers of 1993 and 1994. Section 2 of the report describes the TWIP message formats, Section 3 discusses the 1995 operational demonstration, and Section 4 presents TWIP software design. Section 5 provides case analyses from the 1995 demonstration, Section 6 discusses future work, and Section 7 is the summary.

The Federal Aviation Administration (FAA) is currently sponsoring programs such as the Terminal Doppler Weather Radar (TDWR) and the Integrated Terminal Weather System (ITWS) which will significantly improve the aviation weather information in the terminal area. Given the great increase in the quantity and quality of this information, it would be highly desirable to provide this data directly to pilots rather than having to rely on voice communications. Providing terminal weather information automatically via data link would both enhance pilot awareness of potential weather hazards and reduce air traffic controller workload. The Terminal Weather Information for Pilots (TWLP) program was created to address these needs. This paper will describe the philosophy behind the product, the format of the TWIP messages. and the system design. An interesting weather case from the operational demonstration currently underway will be shown, and plans for the national deployment of the TWIP capability at all TDWR-based airports will be discussed.

The Integrated Terminal Weather System (ITWS) is an FAA-sponsored program (Sankey, 1993; Ducot, 1993) whose objective is to acquire data and products from a variety of weather sensors, integrate the data and create aviation weather products for users, such as Air Traffic (AT) controllers and traffic managers, pilots, and airline and airport operations managers. The goal of ITWS is to increase capacity at airports, reduce controller workload, and enhance safety. The objective of the ITWS Storm Cell Information (StoCel) and Weather Impacted Airspace (WIA) Detection products is to identify storm cell characteristics (echo top, echo bottom, presence of heavy rain, hail, etc.) and airspace that pilots are likely to avoid because it contains hazardous weather. The StoCel/WIA products rely on the integration of pencil-beam data and products and Air Surveillance Radar (ASR-9) Weather Channel data. ASR-9 radars are useful because they cover the entire airspace of interest, perform a volume update at roughly 30-second intervals, and will be the weather representation most widely available to the Air Traffic Control (ATC) community. On the other hand, the ASR-9 has a 4.8° fan beam which results in a vertical integration over the depth of a storm, so information on the vertical structure of storms is lost. In addition, the current ASR-9 Weather Channel may produce false weather regions during ducting or anomalous propagation (AP) conditions. Nearby WSR-88D radars also cover the entire airspace of interest and provide indications of storm vertical structure. However, the volume update rate is typically on the order of 5 to 10 minutes, depending on the scanning strategy. TDWR radars perform volume updates about every 2.5 to 3 minutes, but perform sector scans that do not cover the entire airspace. Integration of the data from these various sensors produces a product that is superior to a product based on any single sensor. Field tests of components of this algorithm were conducted at Dallas-Ft. Worth (DFW) and Orlando (MCO) International Airports during the summer of 1993. The objectives of these tests are to evaluate the technical performance of the algorithm and the validate the operational concept. This paper will describe the algorithm, and discuss the operational concept and functional requirements for the product. A summary of the results and experiences of the Summer 1993 field tests, and a preliminary evaluation of the performance of the algorithm based on off-line and real-time tests will be provided at the conference.