Towards a unified model-based safety assessment

The increase of complexity in aircraft systems demands for enhanced analysis techniques. Methods are required that leverage the burden of their application by reusing existing design and process information and by enforcing the reusability of analyses results allowing early identification of design's weak points and check of design alternatives. This report elaborates on a method that assumes a system specification in an industrial standard notation and allows to perform several formal safety analyses. Based on a collection of failure models and means of specifying safety requirements, the techniques produce results along the lines of traditional methods. We show how to combine traditional techniques, required by the Aerospace Recommended Practice (SAE-ARP) standards, like Fault Tree Analysis, Failure Mode and Effect Analysis and Common Cause Analysis and also how to automate most of the analysis activities. The methods described in this paper can be used as means to support the Certification process.