UK-based air traffic control services provider NATS has introduced a new method of calculating aircraft separation at Heathrow Airport, known as Pairwise separation.
This method, which is part of the Intelligent Approach arrivals spacing tool developed in collaboration with Leidos UK, was implemented in December last year.
Research supporting Pairwise separation was conducted by NATS as part of the Single European Sky ATM Research (SESAR) Programme.
NATS stated that an analysis of the first six months of Pairwise operation indicates notable improvements in operational efficiency.
In comparison to the same period in 2024, the percentage of arrivals without delay has increased by more than six percentage points, while the average arrival delay has decreased by nearly 20%.
Additionally, CO2 emissions have been reduced by 18,600t during this timeframe, stated NATS.
Despite a cap on the total number of flights at Heathrow, Pairwise separation facilitated an increase in the average landing rate during peak hours by more than one movement per hour.
This enhanced capacity has provided additional resilience to airport operations, effectively minimising delays and mitigating the effects of disruptions.
Heathrow Punctuality and ATM head Gary Harman said: “Working with NATS we can already see the incremental improvements that Pairwise is helping to deliver.
“It’s no secret that Heathrow is operating at capacity and innovations like this are a great way to improve punctuality and resilience while reducing our impacts.”
Pairwise separation represents a shift from traditional methods of calculating safe minimum separation between aircraft, which typically rely on six categories based on aircraft weight and wake turbulence.
The new system considers the unique characteristics of individual aircraft types, allowing air traffic controllers to safely reduce separation between certain aircraft pairs. This adjustment increases overall traffic flow and decreases the need for airborne holding.
NATS Queue and Capacity Management Solutions head Brendan Kelly said: “Pairwise was another world first deployment for NATS and while and there are lots of factors that can influence operational performance, these interim benefits paint a very positive picture of the value it is delivering for Heathrow and our airline customers.”
In May this year, an independent assessment confirmed the advantages of space-based Automatic Dependent Surveillance-Broadcast (ADS-B) in the North Atlantic airspace, six years post-implementation.
The review, conducted by aviation consultancy Steer, was commissioned by NATS to fulfil regulatory requirements.
