Mincut-based fault tree analysis revisited and extended for calculating MTBF

It is shown that, with the mincuts given, the Shannon approach is strongly challenged by an approach resulting in subproduct inversions, based on a simple partitioning of the system faults. A simple heuristic is given for an almost optimal determination of i) system unavailability ii)—after a little addendum—system mean failure frequency; the latter for s-independent repairable components. In order to speed up calculations, optimal approximations with prescribed accuracy are possible, both for unavailability and mean failure frequency.