Potential risks of developing commercial hydrogen-powered aircraft: lessons learned from individual contributing factors to system failures in hydrogen occurrences

Abstract

Hydrogen is pivotal to the net-zero roadmap for aviation, offering a sustainable solution to reduce emissions. Currently, there are limited occurrences of Hydrogen-related safety cases within aviation. There have been 222 reported occurrences of Hydrogen-related incidents and/or accidents between 1972 and 2024, sourced from H2Tools. These reports provide valuable insights into potential learning opportunities for the aviation industry as it incorporates early hydrogen infrastructure and operations into its strategy for sustainable aviation. These 222 reports were analysed using Thematic Analysis (TA) methodology, applied with the Human Factors Analysis and Classification System (HFACS) framework to understand commonly occurring failure types and contributing factors. The TA was applied as the study worked with a large secondary dataset of qualitative data, with limited regulation to its content structure. The results revealed that Flow Control Systems were the most common theme of system failures, with a total of 182 (82.0%) occurrences, including 13 accidents, 124 incidents, 40 near misses, and five non-consequences. Furthermore, the theme of Individual Unsafe Acts accounted for 140 (63.1%) of the total occurrences and emerged as the most significant contributing factor across all severity levels, with 12 accidents, 99 incidents, 17 near misses, and 12 non-consequences. Analyses of these key areas can enhance safety standards by targeting events with high frequency of failure and analysing the severity of failure. This can help inform inspection focus, reduce operational risks associated to hydrogen handling in aviation and foster a more resilient environment, capable to adopt hydrogen technologies on a large scale.