It comes as part of the regulator’s work to enable aerospace and drive growth of the sector through fostering innovation and collaboration.

Tim Johnson, Director of Communications, Strategy and Policy at the UK Civil Aviation Authority, said:

“These trials keep the UK on course to be a world leader in hydrogen propulsion.

“We are working with some of the most innovative companies and minds to better understand this technology and how it might be introduced safely in the aerospace sector.

"In doing so, it offers the potential to enable a more sustainable aerospace system and support UK economic growth.”

The projects will create a better understanding of hydrogen technologies, shape future regulation, and ensure that they are safely adopted into the aerospace sector.

Some of the projects involved in the Hydrogen Sandbox include:

Cranfield Aerospace Solutions will use their Project Fresson 1a, to test potential regulation for hydrogen fuel cell electric propulsion systems on aircraft.
Oxford University is exploring the key scientific challenges of pressurising, heating and combusting initially cryogenic hydrogen to enable hydrogen combustion at the heart of gas turbines.
ZeroAvia is setting out how we get to the widespread use of hydrogen-powered aircraft. This includes safe hydrogen fuel storage, distribution and refuelling practices at airfields and on aircraft.
Qdot Technology is developing a zero-emission and long-range unmanned aircraft, with the ability to carry heavy loads. This would be used for logistics, monitoring and servicing offshore operations.
Stratospheric Platforms is developing the ‘Stratomast’, a high-altitude, remotely piloted, liquid hydrogen-powered aircraft system designed to deliver high-capacity low-latency data connectivity direct-to-device.
Rolls-Royce is designing gas turbines that will be compatible with net-zero fuels such as hydrogen. In partnership with easyJet, the project will build a crucial understanding of these emerging technologies.
Intelligent Energy is exploring regulatory and certification challenges associated with integrating hydrogen fuel cell systems into aerospace applications.
Consortium including Highlands and Islands Transport Partnership (HITRANS), Highlands and Islands Airports (HIAL), AGS Ltd, European Marine Energy Centre (EMEC), Orkney Islands Council and Loganair are using Kirkwall Airport aerodrome as a test to explore how hydrogen fuel infrastructure would be rolled out across aircraft and airports in Scotland.
Regional & City Airports Ltd is running trials at Exeter Airport to test different approaches for storing a refuelling hydrogen fuel and fill gaps in existing knowledge
Ultima Forma is developing vacuum containment barrier systems for liquid hydrogen storage. Lightweight composites and the electroformed materials structure maintain a high vacuum and provide a hydrogen barrier.
Swift Aircraft is exploring the application of hydrogen as a fuel source in the development of a new sustainable training aircraft suitable for flight schools
HyFIVE is a consortium of UK aerospace and academic leaders who have joined together to develop, test and validate a modular, scalable cryogenic hydrogen fuel system architecture.
Project 601 is a programme of work at Heathrow Airport to develop an airside ‘test-bed’ for trialling innovative technologies and processes to support the transition to net zero. Specifically, the Sandbox will support demonstration activities involving handling of gaseous hydrogen (GH2) at Heathrow, including delivery, storage, and on-site applications. Uniquely, the project will benefit from support and access to leading Hydrogen research facilities and expertise at Cranfield University, including the Cranfield Hydrogen Integration Incubator (CH2i) and Digital Aviation Research and Technology Centre (DARTeC). Overall, the project aims to deliver the capability to support commercial operations of hydrogen at Heathrow by 2028.

The Challenge, which launched in 2024, has been expanded. Trials will now last three years to increase the development potential for the companies involved. The results from the 2024 Hydrogen Challenge will be published in the near future.

Research Advances Hydrogen-Electric Aircraft