Assessment of Operational Consequences of Aircraft Failures: Using Event Tree Analysis

The purpose of this paper is to describe a methodology that supports an assessment of the operational consequences of failures in aircraft systems and its associated costs, in order to facilitate a correct and efficient decision-making during cost-effectiveness analysis of maintenance tasks within scheduled aircraft maintenance program development. The paper is based on empirical studies of possible scenarios from aircraft failure to operational consequences in commercial airlines. Empirical data was extracted through document studies and interviews, guided by the application of an event tree analysis (ETA). The analysis was performed together with experienced practitioners from both an aircraft manufacturer and commercial airlines, which contributed to a continuous verification of the outcomes of the study. The proposed methodology, which is based on ETA, is considered as a valuable support in the assessment of the operational consequences of failures within a MSG-3 framework. The proposed methodology focuses on assessing the operational consequences of failures and associated economical losses. Hence, in order to enable an estimation of the maintenance tasks' cost-effectiveness, the methodology should be further developed to include a cost assessment of the applicable maintenance tasks. The proposed methodology could be adapted as a support to those involved in the development of aircraft maintenance program. The operational consequences and the probabilities of the proposed event tree can be quantified by the aid of historical data or expert judgment. No other research paper or other available documentation dealing with the assessment of the cost of failures with operational consequences has been encountered by the authors. Hence, the proposed methodology fills this gap and provides a fulfillment of practitioners' needs.