The major issue in aircraft industry is constructing risk management system for safety management because of increasing demand and advancement of the aircraft. This study is to assess the operational risks of aviation using IRPN(importance risk priority number) which is added to importance coefficient from RPN(risk priority number). In FMEA, RPN requires the factors like the occurrence (O), Severity (S), and Detection (D) of each failure mode. Therefore, the severity and detection is derived by the value from Fuzzy-FMEA of expert group. The occurrence is calculated from the accident statistics of IATA(international air transport association) database. Particularly, this study introduces importance coefficient to prevent from RPN distortions. The RPN distortions are decreased by introducing importance coefficient in the result of an experiment. It is also derived from Fuzzy-FMEA. Finally, the critical ranking of risk factors according to IRPN is similar with the existing research.