Courtesy Dotted Yeti / Shutterstock
 
The minimum distance between aircraft ‘wing tip to wing tip’ has been reduced from 23 to 19 nautical miles (nm), enabling greater flexibility in how available airspace capacity is used.
 
It follows the reduction in the minimum safe ‘nose to tail’ separation between aircraft from 40nm to 14nm in March and represents another step towards the end of the traditional system of rigid oceanic tracks, something that will give airlines greater opportunity to fly the most efficient routes and levels, reducing fuel burn and harmful emissions.

 
The change has been made possible following the introduction of near real-time aircraft surveillance using the Aireon global space-based ADS-B service. At the end of March, NATS and NAV CANADA started an operational trial of satellite-based ADS-B surveillance to improve the safety, predictability and fuel efficiency of air traffic over the North Atlantic; the world’s busiest oceanic airspace with over 500,000 flights a year.
 
The ADS-B service has augmented the traditional ADS-C messaging system that delivers aircraft position reports every 14 minutes, with low-latency updates at least every 8 seconds. That leap has made it possible to safely position aircraft closer together, freeing up capacity on the most fuel and environmentally efficient routes while also making the airspace safer.
 
Martin Donnan, NATS director Prestwick, said: “Our trial has been going extremely well and we’re delighted to have progressed its scope as planned. We’re starting to see the realisation of benefits for our airline customers and we’re able to offer the flight levels and routes they want more often, while also enabling them to fly at their preferred speeds.”
 
Since the trial began at the end of March, 4,414 flights have been assigned more fuel-efficient levels, and over 3,400 have been able to fly more direct routes than over the same period in 2018. Over 52,000 flights - more than a third of all eastbound crossings – were also able to fly their most cost-efficient speed, totalling more than 45,000 flight hours. In October the Air Traffic Control Association (ATCA) recognised Aireon, NAV CANADA and NATS with their Annual Industry Award for the successful deployment of space-based ADS-B technology over the North Atlantic.
 
Donnan continues: “The changes enabled through our new ADS-B service allow us to provide a better, more fuel and environmentally efficient service for our customers. It’s also fundamentally safer, with our controllers now able to prevent, detect and recover far more quickly when a flight deviates from the cleared trajectory assigned by air traffic control.”
 
NATS and NAV CANADA are continuing to collect data during the course of their trials and expect to further reduce lateral separations to 15nm from November 2020 when ICAO is due to formally publish new separation standards.