The primary mission of the Terminal Doppler Weather Radar (TDWR) system is to detect thunderstorm-related wind shears and microbursts that are potentially hazardous to aircraft during landing and takeoff operations (e.g.. within three nautical miles on final approach and within two nautical miles on departure). The sources of these wind shears are microbursts and gust fronts. The mechanism by which these wind shears are provided to Air Traffic Controllers is the Ribbon Display Terminal. A secondary mission of the TDWR system is to support traffic management by the detection of precipitation and detection and forecast of gust-front-induced wind shift. This information is provided to the Air Traffic managers (Supervisors and Traffic Management Coordinators) via the Situation Display. The TDWR Program Office tasked Massachusetts Institute of Technology Lincoln Laboratory to survey the first five commissioned TDWR sites in order to assess how well the system was meeting its mission goals and to measure user (Air Traffic Controllers and air traffic managers such as Supervisors, Traffic Management Coordinators, etc.) benefits achieved through deployment of the TDWR. A list of candidate questions was prepared (Appendix A). Site visits commenced on 28 November 1995 and ended 25 January 1996. At each site, interviews began with a tour of the Air Traffic Control Tower. Questions regarding airport configuration, number of operations, and weather impact on operations were asked to provide a context for controller and traffic manager interviews. Users who acted in the capacity of controller were asked questions regarding their perceptions (If the accuracy of the Ribbon Display Terminal messages and their views of the impact (if any) on the effectiveness with which they performed their duties. Users who performed the duties of traffic managers (Controllers-in-Charge, Supervisors, Traffic Management Coordinators) were asked questions about the operational benefits of the products on the Situation Display. After the interview process was completed, the benefits estimates claimed for the TDWR system were revisited.