Scotland's largest regional airline says it expects the first small zero-emission commercial flights to be operating across the country by the end of the decade. By 2040, the airline’s goal is for all its fleet to be zero-emissions aircraft.

But, more important than that, it expects to have played a globally-significant role in the development of a new wave of aviation that is emissions free. A revolution is starting in tiny Kirkwall Airport in Orkney.

The Sustainable Aviation Test Environment (SATE) project is nothing short of the development of a total system for zero-emissions flights: a testing site for aircraft, operating alongside an airline keen to design, trial and certificate new technology.

A key element in that revolution is a small nine-seater aircraft, the Britten-Norman Islander, which has been in use by Loganair since 1967 – and which could well be, in its retrofitted form, the first zero-emissions commercial aircraft in Scotland.

Loganair is an active partner in three future flight projects taking place out of this site. Project Fresson is being led by Cranfield Aerospace Solutions to convert the Britten-Norman Islander aircraft used on the Orkney inter-isles air services to hydrogen fuel cell power, ZeroAvia’s hydrogen-powered aircraft development, and Ampaire electrical-powered aircraft.

These small aircraft are, according to Loganair head of sustainability strategy Andy Smith, just the start.

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ZeroAvia's hydrogen-powered aircraft

He said: “We’ll see a commercial zero-emissions aircraft flying in the UK before the end of this decade. The quicker the smaller aircraft convert, the quicker the larger aircraft convert. Airbus have made some big commitments to hydrogen. They’re saying 2035 or earlier to have a hydrogen-powered airliner flying, which would be impressive.”

What is happening in Orkney is, according to one of its architects, unique in the world. Professor Andrew Rae of the University of the Highlands and Islands said: “Our corner of Scotland is doing things that haven’t happened anywhere before.

“They’re developing infrastructure as well as the technology. And it’s not just the airport, it’s the airspace as well. It’s people looking at new ways to manage the air above our heads so that these things can fly safely, and not conflict with other users of airspace.”

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Aviation threat

It is also vital, as a 2021 study found aviation is responsible for 4 per cent of human-induced global warming. If aviation growth was to continue at its current rate, it could contribute 0.1 degree Celsius to global warming by 2050.

There are reasons this remote island site is taking such a key role in the testing and development of the systems supporting low emissions flight. “If you look at the south of England, airspace is very congested,” Mr Smith said.

“It’s not as good a place to be trying to work out trials. The fact that Orkney is a long way from anywhere is its advantage. You can test and you are not causing any issues with other airspace users.”

All three of Loganair’s partner projects are showing strong progress. In January, ZeroAvia did its maiden flight of a hydrogen fuel cell aircraft.

Mr Smith added: “That’s a big milestone. But there’s a long way to go to having a certified product. “Based on what we’re being told by people who are developing these technologies, we’re going for 2040 for zero-emissions on all our fleet.

“It’s an ambitious target, but we felt that we needed ambition.” Currently, he said, Loganair is open to all zero-emissions technologies – which chiefly, for short-haul, revolve around hydrogen and electric. Increasingly, however, hydrogen is being seen as the frontrunner.

“Hydrogen is currently looking like the most effective solution for us,” said Mr Smith. “Sustainable aviation fuels, which can be either biofuels or synthetic fuels, are very important for a global industry level and long-haul flights which are going to find it harder to decarbonise via hydrogen.

“But we see that we can probably move quicker to net zero on our core operations by going down the hydrogen route. And that’s just a feature of the fact that the aircraft we operate are bit smaller and fly shorter distances.”


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A Loganair Britten-Norman Islander


Hydrogen issues

ONE of the problems with hydrogen, Mr Smith added, is its large volume. He said: “To carry the same energy content as a jet fuel, you need to carry three times the volume, and that’s of liquid hydrogen at cryogenic temperatures – if it’s gaseous you’re looking at six to seven times.”

Another is that it leaks. As Professor Rae put it: “Hydrogen is tricky stuff to keep a hold of because it’s a single atom molecule. It will leak from everything. We will need to deal with those leaks, so they don’t become dangerous.”

Nevertheless, developers are confident about conquering these challenges and even long-haul flights are looking to hydrogen. A FlyZero study, published by the Aerospace Technology Institute, concluded that green liquid hydrogen is the optimum fuel for zero-carbon emissions flights and could power a midsize aircraft with 280 passengers from London to San Francisco.

Among the big challenges, Mr Smith said, is the supply of hydrogen: “There are a lot of industries out there that are saying the only rational route for their decarbonisation is via hydrogen, and everybody needs a bit of the chain for them to move.”

Energy supply is likely to represent the biggest challenge, whatever the source and technology. Professor Rae said: “Whether it’s electricity or sustainable aviation fuels (SAF) or hydrogen, production volumes will not be sufficient currently to cope with aviation demand. There has to be significant infrastructure to generate hydrogen.

“With electricity, aviation is already competing against electric vehicles. Projected demand for hydrogen, especially if it’s competing with domestic heating, is orders of magnitude more than we have current capability for.”

Among Loganair’s partners is Cranfield Aerospace Solutions, whose Project Fresson is taking a familiar small plane, the Britten-Norman Islander, already in regular use for small island hops, and installing hydrogen technology.

Cranfield Aerospace is converting the aircraft to run on a fuel cell with gaseous hydrogen. Jennifer Kavanagh, its chief strategy officer, described 2023 as a “big year” for Project Fresson. “We are hoping to fly by the end of the year.”

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The Herald: Cranfield Aerospace Solutions Project Fresson, copyright Cranfield Aerospace

Cranfield Aerospace Solutions hydrogen-powered Britten-Norman Islander


‘End of humanity’

MS Kavanagh is acutely aware of the need for this technology to develop at pace. She added: “There’s a chance that if we don’t do anything as a human race that my children will see the end of humanity as we know it.”

The Islander was chosen, she said, partly because it was “a cracking little aircraft”. But also, she added, because of its small size and its operational use.

The aircraft is part of a four-phase plan, scaling upwards in size. One of the reasons Loganair has become a key player is that the airline operates a range of planes from tiny Islanders to 50-seaters and above.

Mr Smith said: “Many of the technology providers wanted to start small and scale up. Generally if you’re an airline you tend to operate aircraft of 20 seats and above, or you operate 20 seats and below.

“But because of Loganair’s history, and we’ve run the Orkney island interservice for something like 50 years, we have that capability, yet we’re quite a large airline so we have some management capability to be able to look at the sustainability issues.”

Because of its unique position, Mr Smith added, Loganair felt “an obligation”. He said: “If we don’t do it, who will?”

It is also a necessity to maintain the connectivity of the islands. “People often focus on the idea that flying is something only the wealthy do, a luxury,” he said.

“But for Scotland it’s central to how these remoter communities and economies connect to the rest of the UK. So we have to find a solution.”