A functional hazard analysis based on multilevel flow modeling

Hazardous element such as dangerous materials or high hazardous energy that must be used in complex system hazards will always exist in the system. In this paper, a new hazard analysis technique is proposed which identifying hazard by deviation influence propagation analysis. Using Multilevel Flow Modeling (MFM), a system can be modeled by a set of high hazardous energy, dangerous materials and safety-related information flow substructures, which represent system functions and control functions. Combining with failure mode classes, possible function achievement changes can be determined. A function deviation causal tree of component is introduced, and the influence propagation upon a series of functions is analyzed. In this way, a series of anomaly functions, which are the trigger or initiator events causing the high hazardous energy to unexpectedly release or dangerous materials to leakage, are determined, and the potentially hazards can be identified. The proposed hazard analysis technique is demonstrated by an example of a fuel system on a certain airplane.