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North Atlantic Skies

Representation of the jet streams, wind blowing west to east as result of the Coriolis force. The stronger the wind, the redder on the graphic. Notice the strnegth of the stream over the North Atlantic. The strength and position of the stream changes every day, although the main path remains the same. Image credit:Stormsurfing

There are some 500 flights crossing the North Atlantic ocean every single day (this figure can exceed 3,000 flight a day once the pandemic will be over and air traffic will go back, in time, to pre-pandemic days). Most of the crossing is unsupervised by ATC (Air Traffic Control) since there is no radar coverage. To keep flying safe, each aircraft is assigned a track that ensures a 30 miles horizontal separation, 1,000 feet vertical separation and 10 minutes interval for aircraft on the same track (corresponding to a minimum of 125 miles).  There are 6 (may be a few more depending on traffic and weather conditions) East to West tracks (Zulu, Whisky, X-Rays, …) and six West to East tracks (Alpha, Bravo, Charlie…) that are defined every day (and night) depending of mete conditions and in particular on the wind strength and direction (see the graphic).

An interesting representation of a cross section of a jetstream. Notice the higher velocity at the centre and the areas of clear air turbolence (CAT) that aircrafts have to avoid. Ideally, an aircraft flying the same direction of the jetstream should stay as close to the core as possible, thus gaining relative ground speed, whilst one flying in the opposite direction should try to stay away from the head wind as much as possible. Image credit: US National Weather Service

Notice that the tracks separation, now 30 miles, used to be 60 miles and the shrinking became possible with the more accurate navigation systems of modern aircraft. Since 2019 NATS (the organisation responsible for flights crossing the UK airspace) end NAV Canada (the equivalent for Canada)  have started  to monitor aircrafts using satellite communications and this has allowed to decrease the separation of aircrafts on a given track to as little as 14 miles increasing the overall capacity and allowing more aircrafts to use the more favourable airways.

The problem with the tracks is that they are not optimised for the single aircraft route and result in longer flight with higher fuel consumption and relatively higher CO2 emissions.

The smaller number of flights currently crossing the Atlantic, because of the pandemic has enabled NATS and NAV Canada to experiment with a new system that is no longer using the “tracks” letting each aircraft to plan for the nest route taking into account wind, weather and aircraft type. This is resulting in shorter flight time and lower carbon emission.

It is estimated that the overall saving can be as much as 16% (in winter time when winds are stronger) leading to a decrease of CO2 emission up to 6.7 million tons in a winter season once traffic will return to the pre-pandemic level.

However the current system under experimentation may not work once the traffic level increases over 1,300 flight per day (as mentioned pre-pandemic peak reached 3,000 flights and this number may well increase as the big jumbos have been removed from the sky and lower capacity aircraft will be used).

New software able to organise autonomous systems (aircrafts) into swarms that can intelligently self organise will be required.  This is something that is already being studied in relation to the use of drones to ferry people and goods in a urban environment where separation will necessarily have to be much lower (in this case, however, also the flying speed will be lower).

Anyhow, a tiny benefit from this pandemic (surely not worth it!!!) is that it has opened the door to experimentation of this new organisation of flight paths.

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the Industry Advisory Board within the Future Directions Committee and co-chairs the Digital Reality Initiative. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.