This book provides a solution to ârare eventâ problems without using the classical theory of reliability and theory of probability. This solution is based on the methodology of risk assessment as âmeasure of dangerâ (in keeping with the ICS RAS) and an expert approach to determining systemsâ safety indications using Fuzzy Sets methods. Further, the book puts forward a new concept: âReliability, Risks, and Safetyâ (RRS). The bookâs main goal is to generalize present results and underscore the need to develop an alternative approach to safety level assessment and risk management for technical (aviation) systems in terms of Fuzzy Sets objects, in addition to traditional probabilistic safety analysis (PSA). The concept it proposes incorporates ICAO recommendations regarding proactive system control and the systemâs responses to various internal and external disturbances.