This article largely illustrates the deployment of safety and dependability analysis of a critical aircraft system within a Model-Based System Engineering context. The level of analysis provided here is twofold. A first part of the study examines the process level integration between the traditional System Engineering activities and the safety and reliability assessment operations. Models of engineering activities are given and merged to produce a guideline for the project development and highlight the knowledge management. The second level of this study exemplifies the application of the preceding principles on the product development through the feedback and experience learnt on a ramjet powered vehicle embedded system. This extended instance shows the diverse knowledge materials created throughout the project as well as their imbrications and logical chaining. We mention also how the produced results help in piloting the advances and the validation needs (especially for real time constraints evaluation).