Demonstrations of delivering the Terminal Weather Information for Pilots (TWIP) products to air carrier pilots via the Aircraft Communications Addressing and Reporting System (ACARS) data link were carried out at Memphis and Orlando during the summer of 1994. Six airlines participated in the demonstrations at both airports. The Terminal Weather Text Message and the Terminal Weather Character Graphics Depiction were evaluated using request/reply and forced update approaches. In the first case, the pilot needed to make a request in order to obtain the TWIP products. In the second case, the TWIP message was sent to the aircraft automatically when certain criteria were met (e.g., the aircraft was within 20 minutes of landing and wind shear alerts began at the airport). Five of the airlines used the request/reply approach, and one airline used the forced update approach. Pilot and contoller response to the TWIP products were evaluated using questionnaires. Statistics on message traffic and content were analyzed, and some cases were analyzed in detail to compare the TWIP products with the existing Surface Aviation Observation (SAO) reports. Recorded radio traffic also was analyzed to determine if there was any effect on the number of requests for terminal weather information. Pilots rated the TWIP products favorably, with most indicating that the messages provided improved situational awareness of terminal weather hazards without substantially increased cockpit workload. Controller reaction to the TWIP demonstration was generally neutral, indicating that providing these messages to pilots caused no substantial increase in contoller workload. Further results of the demonstration are discussed in the report, along with recommendations for subsequent TWIP demonstrations.