Abstract: This paper introduced a new model based method for safety analysis to address the problem of failure modes integrity,dynamic failure and data consistency currently encountered in safety assessments for integrated avionics system.The method models integrated avionics system hierarchically with layers of application operation,function and resource.It simplifies a large part of the analysis,the development of fault trees,and can guarantee the consistency of results.Event-B language is used to model application layer to check the integrity of operations modes and AltaRica is used to model dysfunction of system to solve the problem of dynamic failure.The efficiency and practice of the method are illustrated by analyzing safety of auto pilot system through Rodin tool which is used for analyzing operational modes of application and Simfia tool which is used for safety analysis.

Key words: Model based method,Avionics system,Safety analysis