Quantitative risk estimation methodology for flight safety in airline segment of commercial aviation

According to the requirements of the international and state regulatory documents, all aircraft operators (AC) must have implemented and constantly evolving safety management systems (SMS). The functions of the SMS can be divided into two control profiles: flight safety assurance (FSA) and risk management (RM). If the procedures for the FSA control profile can be considered studied and implemented under operating conditions, the RM profile needs its terms to be definite as well as unambiguous and it also needs the scientific and methodological provision of mandatory procedures common to all aircraft operators. In order to avoid ambiguities in the presentation and implementation of the RM process, this article provides the basic standard definitions used in the presented methodology for quantitative risk assessment. The methodology envisages estimating the probability of an aviation event of a certain type (severity) in two ways: either through the statistical probability (frequency) of this type of events after the fact (if the events took place in the estimated period); or through the calculated statistical probability of an event of a less serious type and the conditional probability of the progress of a more serious event. In the formulas given for calculating the probabilities, a previously developed method of indirect estimation of the probability of accidents was used and the ratios of the number of events of different types of severity for each group of causal factors updated to the new statistics: "Human factor", "AC" and "Environment". In order to quantify the level of risk, an updated risk assessment matrix has been proposed and approved in the UTair airline SMS based on the ICAO matrix adapted to control risk management for the FSA. The methodology ensures the fulfillment of the requirements of the Government Decree dated November 18, 2014 No. 1215 by all aircraft operators, its scope can be extended to the SMS of all aviation service providers, taking into account the relevant specifics of the services provided