This paper presents the application of a meta model and single underlying model on an applied avionics system design use case. System models, safety assurance cases and safety requirements are maintained in a central repository. This enables to link these data which are originally developed in unrelated tools. By having such a central repository, traceability can be established, and consistency can be ensured, which leads to less errors and a shorter development time. A meta model was constructed which matches the central repository to enable bidirectional synchronization with an external authoring tool.