Winner of Research Project of the Year: STEM – Times Higher Education Awards 2022
Research led by Professor Paul Williams revealed that transatlantic flights could cut fuel consumption and emissions by hitching a better ride on the jet stream. The findings directly led to the scrapping of an inefficient and outdated flight corridor system in March 2022, delivering immediate environmental benefits.
Aviation is currently responsible for around 2.4% of all human-caused carbon dioxide emissions, and this figure is growing rapidly. Until recently, transatlantic aircraft were forced to fly along the same routes, whether flying from London to New York, or from Barcelona to Chicago, or between any other airport pair. This system, known as the North Atlantic organised track system (OTS), routed transatlantic flights along an invisible multi-lane motorway across the busiest piece of oceanic airspace in the world and had changed little since its inception in 1961. However, forcing each aircraft along the same route meant they were burning more fuel and emitting more carbon dioxide than needed. The route that burns the least fuel, minimises the CO2 (and other) emissions, and results in the quickest journey is different for each airport pair.
Researchers led by Professor Paul Williams with PhD student Cathie Wells analysed around 35,000 transatlantic flights over the period from 1 December 2019 to 29 February 2020 to quantify these inefficiencies. Each day, a mathematical algorithm was used to calculate the optimised routes: routes which are better at tracking the beneficial winds – or “hitching a better ride on the jet stream” – and thereby boosting the groundspeed without changing the airspeed. The team found that taking better advantage of the winds would have saved around 200 kilometres worth of fuel per flight on average. They found that the OTS routes were typically hundreds of kilometres longer than the optimised routes: the average eastbound track was 232 km (4.7%) longer, and the worst eastbound track was 931 km (16.2%) longer. For flights between London Heathrow and New York JFK airports alone, this resulted in 6.7 million kg of unnecessary CO2 emissions in total over the period.
The study showed that abolishing the OTS could deliver emissions cuts that would be significant, inexpensive, and immediate. One week after publication, the study was prominently cited as evidence and motivation for a trial to disband the OTS, jointly announced by the UK’s and Canada’s air-traffic controllers (NATS and NAVCANADA). The trial was successful, and a landmark decision on flight routing followed: from 1 March 2022 the OTS has been permanently abolished for all flights at and below 33,000 feet in the first instance. A second study published by the same team in April 2022 has also demonstrated that further emissions and fuel savings are possible by allowing airspeeds to vary enroute.
The aviation sector needs to reduce its emissions urgently to limit the future impacts of climate change. However, upgrading to more efficient aircraft or switching to biofuels or batteries will be costly and mean the aviation industry might be waiting decades for technological advances to help it decarbonise. This research has demonstrated that providing aircraft with greater route flexibility can provide substantial and immediate environmental benefits via emissions cuts, as well as offering economic benefits (reduced fuel consumption lowers airlines’ fuel costs) and social benefits (faster flights means less time in the air for passengers).
Research team
- Professor Paul Williams, University of Reading
- Professor Nancy Nichols, University of Reading
- Cathie Wells, University of Reading
- Dante Kalise, Imperial College London
- Ian Poll, Poll AeroSciences Ltd.
Press release: Transatlantic aircraft win freedom to surf winds (Feb 2021)
June 2022
Photo by Philip Myrtorp on Unsplash