“…However, a top-down analysis based on the law (2), which is used to describe POS of the systems in case of sudden failures, is valid, for example, for radio-electronic devices [10], whose structural elements are very complex products -subsystems of the lower level. But at the level of components of a mechanical system (MS) [11], degradation failures due to metal fatigue, wear, corrosion, and aging of materials are not described by the exponential law (2), hereat its application in these cases is incorrect.…”