Setting the advanced air mobility fire safety agenda

By Andrew Giacini | September 18, 2022

Estimated reading time 9 minutes, 7 seconds.

The revolution of electrically-powered aircraft has the potential to quiet aviation, reduce the carbon footprint of travel, and further connect communities. Advancements in the development of lithium batteries and other power technologies, such as hydrogen, have shown promising results and may soon be a true contender to replace traditional fuel tanks and combustion engines.

Much like the electric car market, the advanced air mobility (AAM) industry is grappling with retrofitting existing infrastructure, designing new purpose-built facilities, and mitigating the risks that come with the use of non-carbon-based fuel systems. Skyports Image

Early successes include the flight of battery-powered short take-off and landing (STOL) and vertical take-off and landing (VTOL) aircraft. Prime examples include Beta Technology’s Alia-250, which recently flew from Burlington, Vermont, to Bentonville, Arkansas, and Joby Aviation’s S4, which has over a thousand test flights under its belt, as well as the transition of conventional take-off aircraft to electric, such as the Pipistrel Velis Electro. With clear signs of success already, this could be the beginning of a major shift in aviation.

A challenge with this change is that our aviation infrastructure wasn’t built for alternative power sources. Much like the electric car market, the advanced air mobility (AAM) industry is grappling with retrofitting existing infrastructure, designing new purpose-built facilities, and mitigating the risks that come with the use of non-carbon-based fuel systems.

Protecting the public, passengers, and property from those risks is a particular area of focus. No matter how unlikely it is that a fire event might occur, ensuring that safe practices and mitigative measures are in place is essential.

Today, when a passenger boards a commercial flight from Miami to Los Angeles, they probably won’t realize the coordinated efforts that are in place to deal with the very minute chance that an off-nominal event requiring fire response occurs.

It’s also unlikely that they realize those two airports have spent millions of dollars on runway upgrades and specialized fire trucks, that the airports test fire suppression systems regularly, and that each airport runs tabletop and real-life scenario exercises with first responders and emergency services.

The average passenger won’t know that the U.S. Federal Aviation Administration (FAA) and aircraft manufacturers perform simulated and real-life testing of aircraft evacuation procedures and onboard fire suppression systems, which account for every part of aircraft design — down to flame-retardant seat materials and even the impact of the disinfectants that are used to clean them.

The passenger doesn’t need to understand this depth of detail, but it is a critical step in a manufacturer, operator, and infrastructure provider’s efforts to demonstrate compliance, safety, and readiness. 

While the commercial operation of eVTOL aircraft is still several years away, the industry is approaching operations in a very similar manner — iterating aircraft design, testing materials, designing infrastructure, and coordinating with emergency personnel in order to prepare for an incident that will hopefully never occur.

In August, the Aircraft Rescue and Firefighting (ARFF) Working Group (WG) met for its annual symposium, where first responders, airport and heliport operators, pilots, life safety experts, training centers, and fire suppression innovators shared their efforts to continually make aviation safer.

This year, the conference included a discussion on AAM and the transition of aircraft from carbon-based fuels. The session was a continuation of the work occurring in the ARFF WG’s Urban Air Mobility Committee, focusing on wider industry education: how the emergency response community can prepare; what the response community needs or would like to see from aircraft manufacturers and operators; what the AAM industry can do to fit into existing frameworks; and what lessons from traditional aviation incident response are relevant, regardless of fuel type. 

While the goal is the same, the specifics when it comes to responding to jet-fuel fires versus fires from alternative power sources vary. For eVTOL aircraft using lithium-ion batteries, aqueous film-forming foam (AFFF) may not be as effective when the goal is to rapidly cool.

Thermal runaway is almost impossible to stop once it has begun, and while the propagation of leaking fuels isn’t a risk, there is a hazard associated with the production of toxic fumes. Electric aircraft have a lower amount of stored potential energy than an equivalently sized carbon-fueled aircraft, but its release may be highly concentrated. 

When it comes to dealing with a lithium battery fire, the volume of water being spent responding to an electric car fire may not be available in an aviation setting, nor a smart use of a scarce resource in some locations. 

Full extinguishment of a battery may not be necessary based on fire attack objectives. Additionally, purpose-built infrastructure may be distributed throughout a community as opposed to being centrally located at a single large airport with ample access to resources.

However, some aspects won’t change, such as having an informed and practiced response and communications plan, training evacuation protocols based on aircraft type, maintaining alternative landing locations, isolating and managing aircraft posing a risk, and protecting life and property.

Fire is a topic of intense focus for the AAM community and regulators. In addition to the ARFF WG, participation is growing in a number of other groups. The National Fire Protection Association (NFPA) is currently updating infrastructure standards to account for changes in power sources (e.g., NFPA 418).

The European standards organization, EUROCAE, is in the process of standing up a rescue and firefighting service (RFFS) group to evaluate European operational standards for eVTOL aircraft. The General Aviation Manufacturers Association (GAMA) convened an ad-hoc technical group to share learnings and identify gaps that may exist in the realm of fire and aircraft rescue. 

Meanwhile, the FAA’s draft Engineering Brief 105 and the European Union Aviation Safety Agency’s (EASA) Prototype Technical Design Specifications for Vertiports specify the need to address fire-related incidents and risks.

Through these efforts and in direct partnership with communities, regulatory authorities around the world, and subject matter experts, the AAM industry is working to achieve the level of safety expected in commercial aviation. The AAM industry has put a premium on getting it right and solving for problems before they happen while avoiding the placement of new burdens on communities without adequate support. 

Andrew Giacini is Skyports’ regulatory affairs lead in the Americas. He also chairs the General Aviation Manufacturers Association’s (GAMA) Electric Propulsion and Innovation (EPIC) Infrastructure Subcommittee, is a member of the Aircraft Rescue and Firefighting Working Group Urban Air Mobility Committee, and has served on the National Fire Protection Association 418’s pre-drafting vertiport task group.

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