This paper presents the use of a specific layer-wise approach to analyze the results of a FABAC accelerated loading test (ALT) carried out on a flexible pavement with an initial flaw. The approach relies on M4-5n (Multi-particular Model of Multilayer Materials) initially developed for the analysis of debonding in composite materials. M4-5n was recently implemented into a mixed finite element code. This model associated to a Winkler foundation makes it possible to address quite easily problems related to pavements with discontinuities in 3D. The experimental pavement is composed of two bituminous layers and includes initial flaws (metal angles) intended to localize crack growth under repeated moving loads. The pavement is monitored using strain gages and temperature sensors. Moreover, a few FWD campaigns are performed at some steps of the test. The simulations are used to infer the (unknown) pattern of cracking/debonding developing during the first stage of the ALT. Among many patterns tested, one of them is more likely to reflect the experimental facts and is presented hereafter.