This paper focuses on the study of broadband shock-associated noise (BBSAN) emitted by the jet of dual-stream aircraft engines in cruise flight conditions. This work builds on past experience of BBSAN-oriented experimental campaigns conducted within Airbus, and on recent progress made on signal processing techniques and source modeling in the literature in order to gain understanding on the source generation mechanism. A dataset from a flight test campaign is considered and compared to a prediction of BBSAN following the methodology proposed by Wong et al. [1]. In this test, pressure on the rear part of the aircraft is measured on a phased array of flush-mounted microphones placed on the fuselage. On the numerical side of this study, parabolized stability equations are used to model the coherent turbulent structures that develop on the jet mean flow. These wavepackets are combined with shockcell quantities to build the Lighthill’s stress tensor, which is propagated to the nearfield of the source. Computations show that two instability modes per frequency coexist, corresponding to turbulence developing mainly in the inner and in the outer shear layer of the dual-stream jet at dierent convection velocities. Results show very similar wavenumber patterns between flight test and synthesized data. The identified turbulence convection velocities are in good agreement. It is shown that the BBSAN signature is dominated by turbulence developing in the outer shear layer, between the secondary stream of the jet and the ambient flow.