The Use of PHM for a Dynamic Reliability Assessment

The reliability of critical aircraft systems such as braking, actuation or cooling systems has a direct influence on the overall aircraft safety and availability. Thus, an unforeseen failure of such systems can have a huge financial impact due to unscheduled downtimes or even worse, can lead to a safety critical situation. A precise knowledge of these system’s future reliability is therefore of great importance for any aircraft operator. The prevalent tools and processes used to conduct safety and reliability assessments have matured over the last decades. Nevertheless, they still form a rather static process, neglecting the true health state of an individual system. In this paper, it is proposed to utilize PHM methods to develop a dynamic reliability assessment method, which will assess the reliability of a given system at runtime (e.g. during flight), by monitoring and predicting the health status of safety critical components. It will be shown that this novel method provides several advantages compared to the classical reliability assessment process