A Hierarchical Probabilistic Approach for Risk Assessments of an Aviation Safety Product Portfolio

Abstract

Given the current accident rate, the number of fatal accidents is projected to increase in the next several years emphasizing the need for advanced aviation safety research. An initial attempt to develop a generic Aviation System Risk Model (ASRM) suggested that the modeling approach lacked a fully developed contextual domain. Following this initial ASRM, an operational/maintenance ASRM prototype was developed based on case studies of specific aircraft accidents. Past and current research efforts focus on multiple case designs in the context of an aviation accident category and consider case study models in isolation. As a consequence, each risk model yields its particular result and the aviation system risk is interpreted based on multiple different, yet isolated results. The approach adopted in this paper extends the conventional methodology used in previous research efforts and provides a higher-order model by considering the holistic nature of the aviation system. A new meta-case that combines different cases to obtain a single numerical value, termed the safety enhancement value, can be designed using this methodology. The approach suggested in this paper presents a novel application in the aviation safety domain and offers significant promise for risk assessments of an aviation safety product port-folio. While an aviation maintenance-related accident category is used for illustrative purposes, aspects of the modeling approach that connect with organizational factors in the Air Traffic Control (ATC) domain are also addressed.