Wind tunnels, using scaled down aircraft models, are the major source of aerodynamic design data for new aircraft projects. Wind tunnels are indispensable tools for aerodynamic research and aircraft development, and complement the most powerful computers. ETW, the European Transonic Wind Tunnel, was designed, constructed and is operated by the four European countries France, Germany, Great Britain and The Netherlands based on a non-profit policy. It is located in Cologne, Germany. European researchers and engineers harness ETW’s capabilities for advancing aeronautical science into aircraft innovation by accessing real-flight conditions in this cutting edge ground-test laboratory. Training opportunities for researchers and engineers are provided. ETW is the worldwide leading wind tunnel for testing aircraft at real flight conditions. Aircraft performance and their flight envelope limits can be accurately determined with unique quality at ETW long before flight testing of a first prototype. This enables significant reduction in the technical and economic risks associated with the development of new aircraft. Manufacturers from all over the world take advantage of the exceptional features of this high-tech facility enhancing the performance, economic viability, and environmental friendliness of their future aircraft. ETW operation and access complies with ISO9001:2008 quality management.