First crewed liquid hydrogen plane takes off

First crewed liquid hydrogen plane takes off

The Future of Aviation: World’s First Crewed Liquid Hydrogen-Powered Flights


At a small airport in Maribor, Slovenia, a German hydrogen propulsion startup called H2FLY has been making waves in the field of zero-emission aviation. Over the summer, the company successfully completed the world’s first crewed liquid hydrogen-powered flights, marking a major milestone in the journey towards cleaner and more sustainable air travel. This achievement has been the result of the culmination of Project HEAVEN, an EU-funded partnership that aims to demonstrate the feasibility of using liquid, cryogenic hydrogen in aircraft.

While the Soviets did experiment with liquid hydrogen as fuel 35 years ago, H2FLY’s HY4 aircraft has now operated using only liquid hydrogen as fuel, relying exclusively on a hydrogen fuel-cell powertrain for the entire flight. This distinction sets H2FLY’s achievement apart and positions them as pioneers in the zero-emission aviation space.

Liquid hydrogen, compared to its gaseous counterpart, offers several advantages as an aircraft fuel. It is more energy dense, meaning it requires lower tank weights and volume, allowing for increased payload capacity. Additionally, liquid hydrogen unlocks a much greater range, allowing for longer flights without compromising on passenger or cargo capacity. However, using liquid hydrogen does come with challenges, such as the need for cryogenic temperatures (-253°C) for transport and refueling.

The recent test flights with H2FLY’s HY4 aircraft have been met with positive feedback from the pilots, who marveled at the lack of vibrations, noise, and carbon dioxide emissions compared to normal aircraft. One of the pilots, Johannes Garbino-Anton, described the experience as “amazing” and highlighted the seamless teamwork involved in making these flights a reality.

Currently, H2FLY plans to scale their fuel-cell system to megawatt capacity with the H2F-175 system, which would enable longer range and altitudes of up to 27,000 feet. In partnership with Deutsche Aircraft, they aim to retrofit a 30-seat Dornier 328 demonstrator with H2FLY’s hydrogen-electric fuel cells and begin test flights by 2025. Looking further ahead, H2FLY’s CEO, Dr. Josef Kallo, envisions powering a 40-seat capacity regional plane with a range of about 2,000km by the end of the decade. The tests conducted so far indicate the potential for even larger powertrains that could propel aircraft suitable for 80 to 100 passengers.

The introduction of liquid hydrogen as an aircraft fuel has been hailed as a potential “gamechanger” for commercial aviation. However, its success also hinges on the availability of refueling infrastructure. In the case of H2FLY’s Project HEAVEN, they have collaborated with Air Liquide, a French industrial gas supplier, to bring liquid hydrogen for refueling at a commercial airport for the first time. The safe transportation of liquid hydrogen by truck to Maribor for refueling underscores the importance of this achievement both in terms of technological advancements and industry demand.

Founded in 2015 by engineers from the German Aerospace Center and the University of Ulm, H2FLY has been dedicated to developing the hydrogen propulsion system for aviation. In 2021, the company was acquired by Joby Aviation, a California-based company specializing in electric vertical take-off and landing vehicles (eVTOL) for air taxi services. This acquisition further solidifies H2FLY’s position as a leading player in the field of sustainable aviation.

The successful completion of the world’s first crewed flights powered by liquid hydrogen represents a significant step towards a cleaner and more sustainable aviation industry. H2FLY’s achievements have showcased the potential of liquid hydrogen as an aircraft fuel, highlighting its energy density, range, and payload benefits. As the industry moves towards retrofitting existing airframes and developing new aircraft designs, the future of aviation appears to be on a promising trajectory towards reducing carbon emissions and ensuring a greener future for air travel.