This paper addresses the experimental research performed in a new transonic facility reproducing the engine bypass-flow conditions. The aerodynamic effects caused by a surface integrated finned heat exchanger are presented. The novel facility is characterized by a complex 3D test section. Aerodynamic measurement techniques and postprocessing tools were developed to satisfy the requirements and experimental challenges presented by this particular application. Map measurements were performed at five plane locations along the test section. The flow evolution along the bypass duct in the presence of the heat exchanger is compared with results on the clean bypass channel flow. Results are presented concerning distributions of flow velocity, flow direction and total temperature effects, as well as wall pressure distributions. Global and local flow effects introduced by the presence of fin-array heat exchangers are analyzed.