Hydrogen as an aviation fuel: Safety concerns and mitigation strategies

The aviation industry is gradually transitioning towards net zero carbon emissions by addressing its primary source of emissions: aircraft fuel. Among alternative fuels, hydrogen has emerged as a promising solution, offering strong potential to support net zero targets while remaining viable for use in aircraft engines. However, it is imperative to understand its safety challenges and mitigation strategies to ensure this transition occurs safely. Despite growing research on hydrogen in aviation, few studies have focused specifically on hydrogen safety. This study addresses that gap by systematically synthesising both risks and mitigation strategies from publications spanning 2015, when hydrogen safety research began to accelerate, through to 2025, providing a comprehensive overview of current knowledge on hydrogen fuel safety in aviation. Our findings highlight key risks associated with hydrogen storage, leakage, flammability, and material compatibility, while also noting emerging strategies in hydrogen storage and handling. This includes advanced leak detection systems to manage leakage risks, boil off recovery technologies to address hydrogen loss during refuelling, improved insulation for cryogenic tanks to reduce heat transfer, and pressure build up. Reviewing these areas clarifies what is known, identifies where further work is needed, and provides practical recommendations for academics and industry stakeholders. We recommend future research to refine risk assessment models to account for hazards such as boil off gas venting, leakage during refuelling, and the spatial and operational interactions that arise with hydrogen and kerosene fuelled aircraft operate in proximity, including their implications for safety exclusion zones and ground handling.