Rolls‑Royce and easyJet have completed a ground test of a jet engine running on 100% hydrogen, as part of ongoing research into lower‑emission aviation fuels.

The companies said a modified Rolls‑Royce Pearl 15 engine reached full take‑off power while operating on hydrogen during tests at NASA’s Stennis Space Centre in Mississippi. The engine was run through a simulated flight cycle, including start‑up, take‑off, cruise and landing.

The test forms part of a four‑year programme involving Rolls‑Royce, easyJet and other partners to examine the technical feasibility of hydrogen as an aviation fuel. Earlier stages included component and system testing in the UK and Europe before integration into a full demonstrator engine.

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David Morgan, chief operating officer at easyJet, said: “Demonstrating 100% hydrogen operation at scale is a significant milestone and marks an important step towards easyJet’s net zero ambition, supporting the long-term transition to more sustainable aviation.”

Adam Newman, chief engineer of the hydrogen demonstrator programme at Rolls-Royce, said: “This programme has given us the clearest understanding in the industry of how hydrogen behaves in a modern aero gas turbine. Through a collaborative, staged testing approach, we have validated combustion, fuel and control system technologies, and demonstrated the safe use of hydrogen through design, commissioning, maintenance and testing.

Engineers focused on adapting the engine to use hydrogen in place of conventional jet fuel, examining combustion behaviour, fuel systems and safety considerations. Rolls‑Royce said the work has produced data that will feed into future engine development programmes.

easyJet said the project supports its long‑term plans to reduce emissions, while Rolls‑Royce said hydrogen could eventually complement sustainable aviation fuel, depending on infrastructure and regulatory developments.