Root cause analysis of airplane technical failures with Rasmussen's risk management framework (RRMF) based human-machine-environment-procedure (HMEP) taxonomy

This study developed a taxonomic approach based on 30 technical failure occurrences between 2002 and 2020. This framework extends the author's previous work on human-machine-environment-procedure (HMEP) taxonomy through the application of Rasmussen's Risk Management Framework (RRMF), which can serve as a common framework to aggregate or compare datasets collected by different organizations. This RRMF-based HMEP taxonomy was used to categorize the contributing factors of 30 technical failure occurrences into seven mutually exclusive categories and respective subcategories for statistical analysis and other risk management analysis. The RRMF provided a hierarchical structure for these first-layer categories, including government oversight, manufacturer deficiency, company management, company procedure and documentation, people and activity management, technical failure, and environment. The functional block diagram and failure modes and effects analysis (FMEA) were applied to translate the technical failures of 12 environment control system failure cases into FMEA tabular statements. Several failure modes had been identified for environmental control system failure occurrences, e.g., sense line leakage, flawed sensor input, duct crack and leakage, broken part (pin and spring), seal degradation, contamination, tube rupture, mechanical joining defect, poor contact, and unanticipated failure instances for electronic centralized aircraft monitor (ECAM). Each failure mode can provide diagnostic information to identify and fix the environmental control system failure problem more effectively. In conclusion, this RRMF-based HMEP taxonomy provided a mental model to guide the data collection during an accident investigation and subsequently derive accident patterns as the core for Safety Management System (SMS) implementation.