EASA and FAA show 1st iteration plans on H2 Certification
H2may be an (the?) answer to aviation’s global green challenge. Through ICAO, all of its Member Nations have committed to this goal. There are other alternatives, and each may have their respective deficiencies.
The FAA and EASA have devoted considerable attention to this challenge. Below are two articles about their current thinking. \
The FAA published a long, detailed review of the problem, some preliminary thoughts about possible approaches and an extensive “wish list” of Research needed to determine airworthiness of this fuel.
EASA’s initiative was a “seminar” like process and solicited expert opinions. Many thoughtful questions were captured and included in the EU safety agency’s future work. The list of government bodies working on H2 was impressive and characteristic of the continent’s reliance of governmental support.
H2 has been a frequent topic for this Journal; here are a few articles:
- Positive Prospect in HYDROGEN as an aircraft power source
- Conflicting Developments in the Hydrogen Aviation Power Race
- Uplifting Aviation Green news on Workable Nozzles for Hydrogen Combustion
- UPDATE ON H2 PROGRESS TOWARD ZERO CARBON EMISSIONS
- FAA’s FAST awards towards the 2050 Zero Carbon Emissions Goal
- How’s H2 progressing through the Certification Track?
Table of Contents
Executive Summary
Purpose
Technology Overview
Guiding Principles
Existing Standards
Certification Readiness
Required Aviation Safety Research
Roadmap Plan
Near-Term Actions (2023-2028)
Medium-Term Actions (2028-2032)
Workforce
This index for a 26 page Roadmap demonstrates the breadth and depth of the FAA’s and industry’s thinking about introducing Hydrogen (H2) into the US aviation system. This energy source is one of the paths to DECARBONIZATION by 2050, a global goal. Though H2 holds considerable promise, it appears to be significantly disruptive to the existing system as to
- the capture of this gas,
- its distribution to airports,
- the into plane fueling process,
- the supporting infrastructure, etc.
Perhaps the most significant challenge, especially from a safety regulatory perspective, is the determination of the airworthiness of H2 in an aircraft and as a component of the supply chain. As the FAA explains (p.5) this difficult task:
“The use of hydrogen on aircraft presents multiple potential hazards; key among them are fire and explosion resulting from uncontrolled leaks. These hazards must be fully understood and addressed in airworthiness standards and related guidance. In addition, essential aircraft systems, such as an engine, fuel cell, or thermal management systems must be shown to operate reliably using hydrogen. Appropriate regulations and guidance must be developed to assure the safety of initial projects and to provide a predictable path to obtaining airworthiness and operational approvals.”
As recent experiences with innovative certification applications (UASs, aircraft materials, early eVTOL/UAMs), the FAA must be cautious when assessing unprecedented advances in aerospace technology. This absence of actual operations has been preliminarily addressed by the Society of Automotive Engineers (SAE) and the European Organisation for Civil Aviation Equipment (EUROCAE) have a joint working group, AE-7AFC/WG-80, that developed a standard for hydrogen fuel cells for aviation use, AS6858. While they are not EASA or FAA standards, both participated in their development.
SAE International and EUROCAE Publish First Global Guidelines for Airport Hydrogen Fueling Stations
Hydrogen Fueling Stations for Airports, in Both Gaseous and Liquid Form AIR8466
The ab initio creation of standards, hopefully “performance’ rather than “prescriptive”, has no easy historic model; so the FAA has drawn this map (p.10) of how it expects to develop these rules-
“5.0 Certification Readiness The introduction of hydrogen in aviation requires an unprecedented effort in developing necessary technologies. Formidable challenges exist at every step. There are technologies to discover, architectures to explore, and new materials, coatings, and manufacturing methods to develop. Each of these must achieve an acceptable level of safety to gain approval and be used.”
To clarify this unknown, Required Aviation Safety Research ( link to 5 single space pages) is established to learn more about the complexities of the H2 becoming the primary energy source for aviation. The specific points to be explored are suitable for technocrats and the paper should be enlightening for them.
The Roadmap is a first iteration and the FAA expresses its interest in feedback and future enhancements.
EASA holds international workshop in 2024 on certifying H2-powered aircraft
The EASA, which has been engaging in hydrogen platforms through various contracts and projects, hosted its first workshop presenting the challenges, future processes of H2 certification.
On Dec. 17, 2024, the EUROPEAN UNION AVIATION SAFETY AGENCY (EASA) hosted its first international workshop on the challenges and future processes for certifying aircraft powered by hydrogen, with the aim of developing a certification approach that has the support of the entire community.
While sustainable aviation fuels (SAF) are seen as an immediate measure for reducing aviation emissions, EASA believes in the longer term other sources of fuel and technologies will be required for the sustainability of the sector. Innovative and disruptive technologies, such as hydrogen, present possible answers, but will also involve significant change to aircraft designs. A new certification approach is therefore needed to ensure that these aircraft will meet high safety standards.
The workshop, attended by more than 100 people, brought all corners of the hydrogen community together, including representatives of fuel cell companies, academia, research institutes, startup aviation companies and well-established aircraft companies. It also included several international authorities, for example the Federal Aviation Administration (FAA), the Civil Aviation Authority of the U.K. (UK CAA) and the Japan Civil Aviation Bureau (JCAB).
“The move to sustainable aviation is a global project necessitating a harmonized approach,” says EASA certification director Rachel Daeschler. “We all need to work together to ensure that the hydrogen-powered aircraft of the future, and its ecosystem, is safe as well as sustainable. To achieve that, we must make sure that knowledge is shared so that we fully understand all aspects.”
Hydrogen-powered aircraft will have a very different design from today, the EASA explains. A change in the certification approach will be required due to the complexity of the integration of hydrogen as a fuel, including the boundaries to be set and the interfaces among aircraft systems. Defining the right certification approach and cooperation among authorities is therefore crucial.
In addition, while use of hydrogen as a fuel is an important research topic in the academic world, the AVIATION SECTOR HAS NO IN-SERVICE EXPERIENCE WITH SUCH AIRCRAFT, as they are not yet developed. This poses safety challenges as there is limited knowledge of the key factors to make flying with hydrogen-powered aircraft safe. The workshop participants agreed that more ATTENTION NEEDS to be paid to the application of technologies in aviation and to the exploration of technology bricks, such as HYDROGEN STORAGE, and to airworthiness considerations, like FIRE AND EXPLOSION PREVENTION and other similar aspects.
Industry presented some ongoing projects and topics currently being explored, like WEIGHT DISTRIBUTION, FUEL TANK DISTRIBUTION, STORAGE OF LIQUID HYDROGEN, AND FUEL CELL STACK AND SYSTEMS. These made it even more evident that the challenges ahead are numerous, and that working together and sharing results at a global level is essential. The discussions that followed raised several main questions regarding
- certification boundaries,
- approvals for fuel cell equipment,
- weight restrictions (for small aircraft)
- and more.
What was clear to all participants is that the current levels of safety must be at least maintained.
The involvement of authorities at an early stage was agreed, but also the right time for that step was discussed, as it was considered that a certain maturation of the technology is needed to engage authorities in an effective manner. The role of the operators and when and how to best to engage them was also debated.
Many projects are already underway to support the transition to new technologies and foster working together. This includes EASA Innovation Services[1], as well as EU Research programs and initiatives, such as Clean Aviation and Alliance for Zero-Emission Aviation (AZEA) as a means to work together and as a platform to share and disseminate knowledge.
Presentations were contributed by Toyota, Apus, Airbus, PowerCell, Rolls-Royce, the German Aerospace Center (DLR), EUROCA, Azea (see above), SAE International, the General Aviation Manufacturers Association (GAMA), the FAA, UK-CAA, Clean Aviation (see above), CONCERTO, MTU Aero Engines AG and Cranfield University HyPER project (Bulk Hydrogen Production by Sorbent Enhanced Steam Reforming). [ALL LINKS TO THE HYDROGEN SECTIONS OF THE ORGANIZATION]Visit the EASA’s international workshop webpage to access presentations from the event.
[1] Innovation Services are offered by the European Union Aviation Safety Agency (EASA) to external stakeholders to support the introduction of new technologies or innovative solutions. Stakeholders interested in receiving technical advice services prior to or outside of an actual certification process conducted in accordance with Commission Regulation (EU) No 748/2012 and its Annex I (Part 21) can apply for Innovation Services. Innovation services are one of the tools in EASA Research and Innovation portfolio, and contribute to building for industry a regulatory framework that allows — with legal certainty — to develop new ideas and to demonstrate that what industry develops is safe.
