Europe Test Milestones Push Hydrogen and Hybrid-Electric Flight Closer to Engine Demonstration

June 25, 2026

Avio Aero and GE Aerospace used the test rig pictured here at DLR Institute of Space Propulsion in Lampoldshausen, Germany to conduct GE Aerospace's first engine restart test using hydrogen in simulated altitude conditions. (Image: GE Aerospace)

Avio Aero and GE Aerospace have completed a pair of Clean Aviation test milestones in Europe that move hydrogen combustion and hybrid-electric propulsion from component research toward the operating conditions required for future aircraft engines. The work supports technology development for the CFM International RISE program and brings together engineering teams in Germany, Italy, Poland, and Türkiye with European research partners focused on lowering the environmental impact of next-generation propulsion.

The hydrogen milestone was completed under HYDEA, a Clean Aviation project led by Avio Aero, at the DLR Institute of Space Propulsion in Lampoldshausen, Germany. Engineers conducted GE Aerospace’s first engine restart test using hydrogen in simulated altitude conditions, addressing one of the key operability challenges for hydrogen-powered flight: relighting an engine quickly and reliably in cold, thin, dry air. Because hydrogen burns faster and hotter than conventional jet fuel, the test required a dedicated hydrogen sector combustor rig and a synthetic air generator using vaporized liquid oxygen and nitrogen to reproduce flight-like atmospheric conditions.

A central focus of the testing was the use of a multi-cup hydrogen sector combustor rather than a simpler single-cup arrangement. The multi-cup geometry gave engineers a more representative view of how hydrogen flames propagate through a combustor and allowed improved placement of an ignition system designed specifically for hydrogen operation by Unison. High-speed imaging at DLR enabled observation of cup-to-cup flame propagation and igniter-to-flame interaction, data that will feed into the design of a full annular hydrogen combustor test rig.

In parallel, Avio Aero and GE Aerospace’s Munich engineering center completed testing of a proprietary fuel cell system at DLR’s BALIS facility under the AMBER Clean Aviation project. The megawatt-class system was evaluated across simulated short-range and long-range flight profiles, including transient operation from idle to maximum power. That capability is critical for hybrid-electric architectures because aircraft propulsion systems must respond rapidly to changing power demands during climb, cruise, descent, and contingency conditions.

Together, the two campaigns target different but complementary barriers to lower-carbon flight. Hydrogen combustion research is focused on making a turbine engine operate safely and reliably with a fuel that behaves very differently from kerosene, while the fuel cell testing advances electric power generation and integration at propulsion-relevant scale. Both are important to hybrid-electric and hydrogen-powered aircraft because future propulsion systems may combine turbines, electric machines, power electronics, batteries, and fuel cells in architectures that must be validated under realistic thermal, pressure, and transient-load conditions.

For the broader aerospace industry, the significance is that these tests convert sustainability concepts into measurable engine-system data. Establishing a hydrogen relight envelope and demonstrating high-power fuel cell transients do not, by themselves, deliver a certified aircraft engine, but they close technical gaps that must be solved before new propulsion architectures can move into flight demonstrators. In that sense, the European test campaigns mark practical progress toward the propulsion technologies likely to shape the next generation of commercial aviation.

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