How can we ensure hydrogen safety at the airport?

By Jim Nixon - February 14, 2022

In psychology we learn about so-called flashbulb memories. These are memories that seem to be part of the national, or even international consciousness: where were you when JFK was shot?; when Princess Diana died? These flashbulb memories are typically vivid and detailed. I wonder whether this can be extended to a kind of "flashbulb association".

When discussion of hydrogen as a new aircraft fuel comes up in conversation, somebody will usually mention the hydrogen supported airship, The Hindenburg. Using hydrogen as a fuel more generally is placed conceptually next to the image of this fiery accident, forming an enduring association. No matter that by the time this image was photographed, any hydrogen had likely dissipated due to its buoyancy, or that hydrogen does not burn in air with a particularly visible flame, or that materials that comprised the superstructure of the airship were highly combustible. It is the hydrogen that is associated with these images.

Much has changed since 1937. With increasing political discourse on climate change and the need for more sustainable aviation, new fuels are a focus of research at Cranfield University. These fuels include hydrogen. Unlike hydrocarbon-based fuels like kerosene, hydrogen does not produce carbon dioxide as a product of combustion. Caution is required here, since energy is required to make, store and transport hydrogen and these factors must be weighed in any reasonable discussion of sustainability. That said, hydrogen may well represent a more sustainable aviation future.

One thing is certain - if we choose to move into a hydrogen aviation system, the work that people do will change. Currently, the aviation system manages hydrocarbon fuels extremely well. At the sharp end, ground-handling, fuelling and fire response will need to work with new systems, procedures, and technologies that a new fuel infrastructure may bring. GO-Lab at DARTeC is currently investigating ways in which to understand and specify these new systems of work in response to changing technologies that include new fuels.

The airport fire service is one area that will need to evolve in response to changes in fuels. Uniquely, Cranfield Airport fire service have already overseen hydrogen-fuelled aircraft at the airport since ZeroAvia was based here for a time undergoing testing. Recently, a series of decision-making interviews have been conducted with the fire service at Cranfield Airport. These activities will inform new hydrogen familiarisation materials as part of a wider project. These detailed interviews have shown that while some aspects of the work will remain the same, others will change the way in which the fire service respond to and manage incidents.

It is also likely that refined technologies may be needed together with new procedures and training to support a hydrogen infrastructure. Our interest in human factors and the way that people work is now extending into this area.

accident simulation

One example of change are the cues that firefighters use to gauge response to fire. These cues, developed through training and experience, allow effective decision making and situation assessment by crew commanders and their teams. For example, kerosene fuels like Jet A-1 are liquids, visible to crew when leaking or pooling. Kerosene fuels have a strong smell, and this cue can be used to detect the presence of fuel or to judge the amount of fuel in an area. Kerosene fuels burn with a visible flame and can produce large quantities of black smoke, related to the amount of fuel burning. Finally, specialised airport fire services have knowledge of the typical locations, and underlying fuel supply infrastructures within aircraft. This knowledge may also need to evolve as different types of aircraft are developed to best exploit hydrogen as a fuel.

That said, firefighting more broadly does manage hazards that overlap with some of the more unusual aspects of hydrogen fuels. Methanol is produced for use in many industrial processes and this fuel burns with a flame that is near invisible in daylight. Acetylene is an extremely flammable gas used in welding and industrial processes that can form explosive atmospheres. Knowledge sharing and research between the aviation and manufacturing domains may well inform a new hydrogen infrastructure. For human factors and ergonomics, these are exciting times in aviation as these new working practices and technologies are being designed and specified. GO-Lab continues to work with users, including the airport fire service, as new innovations in aviation present new demands, new technology and new ways of working to ensure continued high levels of safety in the wider aviation system.

With thanks to Filippo Pragliola (Fire Service Manager), Paul Renforth (Crew Manager), John Power (Deputy crew manager) and the team at Cranfield Airport Fire Service.

Please note that the images contained in this blog post depict accident simulations and not real events. 

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