Wheeling Bracking System : A Pragmatic Demonstration of MBSE and MBSA Coupling
Generally, in aeronautics, Safety activities contributes to developing several system performances such as reliability, operational availability and testability. In accordance with the recommendation described in ARP 4761 (ED135) of the standardized safety process, the safety analysis approach from a very safety-oriented point of view is carried out on the conceptual base:
· Functional Hazard Assessment (FHA): A study of high-level functions to determine their potential failures and to classify the risks associated with specific fault configurations based on their severity.
· Preliminary System Safety Assessment (PSSA) Preliminary System Safety Assessment (PSSA): Preliminary safety architecture validation through the characterization of causes leading to each dreaded event and preliminary assessment of the probability of occurrence. Occurrence of most of the dreaded events identified during FHA.
· System Safety Assessment (SSA): A system safety assessment (SSA) that assesses the conformity of a system, such as produced, maintained, repaired and used, with the safety requirements derived in particular from FHA and the PSSA;
· Common Mode Analysis (CMA): Additional studies that support the PSSA and SSA for risks related to common causes that may have multiple origins.
In addition, the design or architecture of complex systems is set up on recent work from Model Based System Engineering (MBSE). Indeed with increasing complexity of systems, model-based Systems Engineering (MBSE) is becoming the most relevant and robust method for designing and modeling complex systems. This method of engineering can rely on different languages, in particular SysML (System Modeling Language) (OMG, 2012).
In the same vein, dependability activities can take advantage of these system architecture models to perform appropriate analyzes. A pragmatic approach would be to bring system engineering and operational safety closer together in order to facilitate and co-ordinate safety studies with the aim of mastering and, above all, reducing development costs by streamlining the activities inherent to each discipline. These two domains with different concepts and approaches are not easily interoperable. Existing research studies are therefore trying to find ways to link them or bring them into coherence methodologically.
Finally, in spite of all the initiatives of coherence between the architecture models and the models of propagation of the failure (in the MBSA sense), the state of the art does not allow to conclude that there exists genuinely methods or tools that ensure the digital continuity between these two activities..
The Safran coupling architecture and safety models approach and prototype, using CAMEO Systems Modeler and the safety research platform OpenAltarica, will provide new modelling capabilities to complement and robustify both the method of activities synchronization and transformation tools guaranteeing thus a digital continuity for the co-development of the system of interest. The demonstration and results done on an existing Wheeling Bracking system architecture, will presents the coupling process and tools.