A coaxial supersonic facility has been upgraded in the anechoic room of the Centre Acoustique (LMFA, Ecole Centrale de Lyon) to reproduce a supersonic fan flow in forward flight. This paper first presents this new facility and some validation tests. A and B screech modes are characterized. Near-field microphones can well discriminate these two modes. A chaotic behaviour is found for mode B, which cannot be explained by mode switching. The effect of secondary flow on screech is essentially a decrease in frequency. Frequency jumps and hysteresis have also been observed with flight speed.