An Ongoing Safety Risk Assessment and Determination of Correction Time Limit for Civil Aircraft

To ensure the ongoing safety of aircraft, it is necessary to conduct risk assessment for those events that occurred during routine operations. Consequently, the corresponding corrective actions should be accomplished within the compliance time if the event was ascertained to be unsafe. However, the existing models of risk assessment and determination of the correction time limit have not dealt with the time-varying failure rate of components. Based on the Gunstone method, this article considers the event risks of the fleet at different correction time limits, combined with the Monte Carlo method to establish a model of risk assessment and determination of the correction time limit. Based on the event risk level and the risk per flight hour, the risks of the event under the condition of no corrective actions and corrective actions with different time limits were assessed, respectively. The unsafe status of a certain fleet and the correction time limit were determined based on the risk criteria. Finally, a case analysis was given to show the feasibility of the model.