Impact of Operational Reliability Re-assessment during Aircraft Missions

International audienceDependability assessment, by system manufacturer, during aircraft design, based on stochastic modeling, is common practice, but model based operational dependability assessment in the way described in this paper and in real-time is seldom done. Usually, the stochastic assessment addresses aircraft or mission safety, and does not specifically tackle aircraft maintenance during its operation. This paper will address an aircraft mission operational reliability as resulting from component failures, environment changes, and maintenance facilities offered at the various stops involved in the mission. We will show how the on-line assessment of operational reliability will help adjust an aircraft mission, in case of major changes during the mission. The assessment is made possible thanks to the building and validation of a generic dependability model that is easily i) processed for the assignment of an initial mission, and ii) updated during mission accomplishment, following the occurrence of some specific major events. The generic model can be built as early as the design phase, by engineers who are specialist in dependability assessment, based on stochastic processes. Model update and processing, during aircraft operation, can be achieved by operators who are not necessarily familiar with stochastic processes in the way that they are being applied in this research. We will present examples of results that show the valuable role of operational dependability re-assessment during aircraft missio