Evaluating Liquid Hydrogen Aircraft for Medium-Range Commercial Aviation: A Techno-Economic and Safety Assessment

This study investigates the feasibility of liquid hydrogen (LH₂) as a sustainable aviation fuel by examining often ignored operational issues. The paper starts with a description of overall motivation for reduction in carbon emissions, highlighting the fact that climate change is very much a reality and air travel contributes nontrivial amounts to global greenhouse gas emissions. A logical path forward using proven technologies towards net carbon negative (NCNeg) aviation is presented. As with other technologies, it is shown that LH2 -powered aviation not only runs the risk of exacerbating climate change by introducing NOx into the atmosphere, but these efforts waste valuable resources that could be used on net NCNeg technologies and implemented today. Still, it is shown that there exists an investor-government-regulatory ecosystem around LH2-powered aircraft that is robust, well funded, mutually supporting and fatally flawed. It is shown that nearly all technological efforts involving LH2 aviation have ignored operational constraints that render this mode of travel fundamentally impractical and a technological “dead end” because of unsurmountable challenges related to ground operations. This paper evaluates key safety, infrastructure, economic, and operational hurdles. To demonstrate these challenges, a custom Hydrogen Aircraft Modification Model (HAMM) was developed to estimate fuel requirements and Boiling Liquid Expanding Vapor Explosion (BLEVE) hazard distances for hydrogen variants of the A320neo and A350 operating out of two example airports. A safety analysis shows that LH₂ aircraft would require extremely large new airport infrastructure due to large flammable cloud and explosion hazard zones. This in turn necessitates large infrastructure investments, ground footprints, ramp separations, and landing fees while generating extreme reductions in operational tempos, passenger and cargo throughput and profitability. Economic modeling demonstrates that while LH2 aircraft may or may not be feasible in the air, the ground operations issues are so severe and hazard mitigation schemes so costly that LH2-powered commercial aircraft of nearly every scale will be impractical for the foreseeable future.