The PLASTUR project attempted to address a cognitive diagnosis problematic i.e. to understand the problem solving strategies used by operators on a simulator. Carried out by a multidisciplinary team, this research, in its fundamental aspect, aims to confront analyses made almost exclusively from real situations in an ecological context with data obtained by a model in an artificial context. As regards the cognitive modelling of problem solving in natural situations, PLASTUR uses models from different fields of research (cognitive psychology, artificial intelligence) applied to the same set of data. This comparison between the two models highlights the specificities and the complementarities of the two approaches. From a more applied point of view, the objective is to define, with our industrial partner, an interactive learning environment based on the simulator and integrating an intelligible diagnosis module used both by tutors and learners.