Reliability and safety assessment with AltaRica for complex aircraft systems

Technology is constantly improving, thus aircraft systems are becoming highly-integrated and more complex. These systems are safety-critical and consequently must be carefully designed, analyzed and evaluated. In order to overcome this complexity increase in aircraft systems, this paper puts forward reliability and safety assessment techniques and methods based on the use of formal design language AltaRica and associated tools to obtain a formal model that is suitable to perform reliability and safety assessment of the system. Through the workbench based on AltaRica, graphical interactive simulation is performed to understand how failures propagate inside the system. Then a model checker is used to test whether the qualitative requirements are valid and fault tree analysis is established to produce a Boolean formula that describes all the sequences of failure events. And a hydraulic system is used to validate the approach. As a main result, these tools and the approach are very efficient to check whether qualitative reliability and safety requirements are fulfilled.