Modelling and monitoring the decay of equipment reliability

Results of an investigation into the reliability degradation of airborne equipment are presented. The aim of the investigation is to automate the reliability monitoring function as much as possible. Results have demonstrated that the methods outlined are workable in practice. The service life performance of a range of equipment in a variety of operating environments can be described by the Duane model with adjustments to allow for reliability decay. This reinforces previously reported findings. The model is applicable to other rate parameters such as maintenance man-hours per operating hour or no-fault-found rates. It is superior to methods currently in use to identify performance degradation when time-between-failure data is not available. Use of this model improves predictions about the long-term performance of equipment, which enables a better estimate of logistics and maintenance resource requirements