Transatlantic aircraft win freedom to surf winds following Reading study

University of Reading news release | 8 February 2021

Aircraft on transatlantic flights will soon be able to change their routes to take maximum advantage of favourable jet stream winds and save fuel, in a landmark decision on flight routing following University of Reading research.

National Air Traffic Services (NATS), the UK's national provider of air traffic control, announced last week that it would be temporarily disbanding its allocated flight paths system while air traffic is low due to the Covid-19 pandemic.

This will allow aircraft to be assigned more efficient routes to better surf tailwinds or avoid headwinds, where air traffic controllers are satisfied they can do so while maintaining a safe distance from other flights.

The announcement came days after research was published by the University of Reading showing aircraft could save up to 16% of fuel, and therefore reduce emissions and journey times, if they had the flexibility to make better use of the jet stream winds.

Professor Paul Williams, an atmospheric scientist at the University of Reading who co-authored the research, said: "It is exciting to see the North Atlantic flight tracks abandoned - albeit in a limited trial - and that the evidence provided by our research was acknowledged in the announcement.

"We have shown that providing aircraft with greater route flexibility can provide substantial and immediate emissions cuts, which is crucial given that the aviation industry might otherwise be waiting decades for technological advances to help it decarbonise."

Under the trial, NATS will work with its airline customers and its Canadian counterpart NAV CANADA to allow airlines to choose their own bespoke routes to maximise fuel efficiency and ground speed.

They will use new satellite technology, which has allowed more accurate tracking of North Atlantic air traffic since 2019, to ensure this can be done while maintaining a safe distance between aircraft.

NATS provides air traffic navigation services to aircraft flying through UK-controlled airspace, and now operates in more than 30 countries around the world.

Its air traffic control services keep aircraft safe by allocating each a fixed altitude and flight path that maintains a minimum distance of five nautical miles horizontally and 1,000 feet vertically between them.

For transatlantic flights, this means aircraft keeping to an allocated pathway on the NATS Organised Track Structure, a high-altitude highway system of up to 12 tracks.

Although these tracks are updated twice daily based on changing winds, they are rigid regardless of where in Europe or North America an aircraft takes off or lands. They also have fixed capacities, meaning the path assigned to any transatlantic flight is rarely if ever the most fuel or time efficient route.

'Benefits within our reach'

The University of Reading study revealed that the average track between New York and London was around 200 kilometres longer than the most efficient route based on jet stream winds. This added up to a total reduction of 6.7 million kilograms of carbon dioxide emissions being possible over a three month period.

In a blog referencing the Reading study, Jacob Young, Operational Performance Manager at NATS, said: "This has undoubtedly been a terrible 12 months for aviation, but the dramatic fall in traffic we've seen across the Atlantic has given us a window of opportunity to do things differently, and to introduce things more quickly than otherwise might have been possible.

"So, we're going to disband the Organised Track Structure on days where our ATC supervisors don't believe they are necessary."

He added: "Our hope is that analysis of these flights, together with other tabletop exercises, will give us the evidence base we need to decide on the value of more permanent changes.

"And as traffic begins to return in the months and years ahead, the kinds of benefits Professor Williams and his colleagues have highlighted might be within our reach."

Cathie Wells, the PhD meteorology researcher who worked on the recent University of Reading study, said: "It is hugely satisfying to see my research having a genuine impact on the aviation industry, and potentially helping to make a real difference in the fight against climate change.

"We are thankful to National Air Traffic Services for putting science at the forefront of their work and taking this opportunity to make flights more environmentally friendly."