Anyone who sits on a transatlantic flight from London to New York is responsible for emitting an average of 670 kilograms of carbon dioxide. However, this amount of greenhouse gas emissions could be lower if the aircraft takes a route that makes better use of the wind. This is the conclusion of a group of researchers led by the British mathematician Cathie Wells in a new study.
Motorway without radar
The researchers show that on flights from Europe to the USA you use up to 8 percent less fuel, and on flights in the opposite direction even up to 16 percent less if you follow a wind-optimized route. Such a route guidance is not yet possible with the current means of airspace management, but the necessary technology is in the starting blocks.
“At the moment there is a so-called ‘Organized Track System’ for transatlantic flights,” explains Christian Kern, head of air traffic control at Austro Control. “Once a day, the route for a kind of freeway is determined, on which the majority of the flights move.” Usually, flights to the USA are carried out in the morning, flights to Europe from the afternoon. This increases the capacity, because increased safety distances must be observed above the sea. If the distances from airplane to airplane are 5 nautical miles (9.26 kilometers) over land, it is sometimes 40 miles (74 kilometers) or more over the sea.
What is missing over the ocean is the continuous radar monitoring of air traffic. Kern: “It is entirely the responsibility of the pilots to follow the given route.” If air traffic control had a precise and reliable overview of what is happening in the sky, the safety distances could be reduced and weather conditions could be more flexible. This should be made possible in the future by improving satellite navigation. Aircraft should send their position signal (ADS-B) transmitted by satellite to air traffic control. The signal is sent by radio over land. The necessary satellites for the future system (Iridium Next) are already in orbit.
“At the moment the track system is relatively rigid. More individual routes could save time and fuel, ”says Kern. What the researchers propose in their study makes sense and corresponds to a long-standing wish of the airlines. By adapting to current wind conditions, you can blow from west to east at great heights Jetstream– Make better use of the wind over the Atlantic and avoid strong headwinds.
The airspace over Austria shows which increases in efficiency are possible through individual routes. There has been a “Free Route Airspace“. Aircraft can choose the direct route without having to stick to predetermined routes. Kern: “Something like that would also be a great thing over the Atlantic.”
Cathie Wells and her colleagues verified their concept by doing calculations for 35,000 flights that took place from December 2019 to February 2020. In this period alone, wind-optimized routes could have saved 6.7 million kilograms of CO2 emissions.
Aircraft engines are currently still completely dependent on liquid fuels. Kerosene can, however, be replaced by so-called “Sustainable Aviation Fuels” (SAF), e.g. B. Biofuels or synthetically produced “eFuels” from solar and wind power
Die Austrian Airlines have recently started offering to customersto offset their flight emissions by purchasing SAF. The partner company Compensaid promises to use the money to buy SAF, which is currently much more expensive than kerosene