Reassessment of aviation risk safety barriers using stochastic and lexical uncertainty.

Results of many investigations and statistical data indicate that aircraft accidents are an iceberg phenomenon for understanding the gap among traffic management, operations, and aviation systems. Although the regulator has established a safety barrier as a defense mechanism against hazards, many accidents and incidents continue to occur. Instead of conducting a comprehensive assessment of an accident/incident prevention system, the evaluator conducted a common audit investigation to determine the causal and contributing factors of accident. Current problems of concern in aviation safety management involve a series of constraints, evaluation methods, and complex decision-making processes. Uncertainty in these problems adds complexity. Uncertainty has characteristics such as randomness and vagueness; in nature, both might occur concurrently. The method is based on incorporating probability (randomness) and fuzzy logic (vagueness) to better represent real-world systems. Cumulative Distribution Function (CDF) and Fuzzy data processing provide some insight into the results of this research. Viewed from a stochastic perspective, all variables are valid, and from a lexical uncertainty perspective, the assigned membership function could provide a proper fuzzy partition. Based on the calculation, this research proposed new safety barrier rates, such as "poor visibility" is below 5.9 km for non-instruments and below 3.56 km for instruments, "unsafe crosswind" is above 6 Knots for Aircraft Mass > 5700 Kg and above 3.2 knots for Aircraft Mass < 5700 Kg. Also, for the rate of pilot experience, it needs to pass 3485 h (flying) to become a Pilot in Command in a particular type of aircraft.