MAINE Flow (for Multimodal Acoustic ImpedaNce Eduction with Flow) is a large-scale duct permitting the study of the acoustic properties of liners with flow and acoustic conditions typically found in nacelles of aircraft engines. In particular, the incident acoustic level can go up to 150 dB and the flow velocity up to Mach 0.6. Compared to other large-scale experiments, this facility permits a precise control of the modal content and amplitude, as well as the measurement of the scattering matrix of the liner. In this paper, we describe direct and inverse methods implemented to allow impedance eduction. For the direct method, the challenge comes from the large size of the duct cross-section that induces complex acoustic fields. A numerical optimisation lead to an experimental set-up using two liner samples facing each other and a 40 microphone antenna. The inverse method is based on a 3D Multimodal Method that computes the sound field for a uniform flow. Then, the impedance is found by minimising the difference between the experimental and numerical values of the multi-modal scattering matrix. These two methods are applied on classical liner geometries in order to compare the results against model and other ducts characterisation.