Crash simulation analysis process is a complex task because of the enormous data to analyse and the integration of different disciplines. This paper is integrated within a research about developing a diagnosis support system of car crash simulation. The overall purpose is, based on organisational and individual knowledge, to provide diagnostic support for experts. This paper only focuses on early difficulties encountered within this research. The knowledge about car crash simulation process is implicit. The objective is to build a methodology for eliciting implicit knowledge from experts.