The current research focuses on the aerodynamic investigation of the three dimensional turbofan bypassflow and its interaction with a finned air/oil surface heat exchanger integrated at the inner wall of the secondary duct. This paper addresses the experimental methodology employed in a new transonic facility characterized by a complex 3D test section. The development of accurate and relatively short time response measurement techniques is essential for the evaluation of the flow by means of map measurements at different locations along the test section. Flow angles, total and static pressures are computed using a new methodology for the processing of the pressure readings acquired by means of hemispherical five-hole probes. The sensibility of the probes and the errors on the angle determination are analyzed. Errors lower than 0.4 deg. for the determination of yaw and flow angles are obtained. The response of the shielded thermocouples designed for the temperature measurements are studied by means of conjugate heat transfer simulations. The numerical methodology is described and the steady and transient temperature effects evaluated. An innovative procedure for shear stress measurements based on oil-dot techniques is discussed and applied on a representative test bench for validation. Results are comparable with theoretical and empirical wall shear stress correlations for the case of a flat plate in subsonic flow conditions.