New tool allows dense Heathrow approaches

LONDON - A new arrivals spacing tool calculates safe and efficient gaps between aircraft approaching London Heathrow. British air navigation service provider NATS credits the "Pairwise" extension to its "Intelligent Approach" system with "a cut in carbon emissions, better punctuality and greater operational resilience".

Developed jointly by NATS and Leidos UK, Intelligent Approach was first introduced at Heathrow in 2015, where its use of dynamically calculated time-based separation has cut headwind delays by more than 60 percent. An extension package - "Pairwise" - is now adding to these benefits.

"Analysis of the first six months of operation of Pairwise has revealed benefits when comparing the same period in 2024. The percentage of arrivals with no delay has improved by more than six percentage points, average arrival delay has fallen by almost 20 percent and overall CO2 emissions are down by 18,600 tonnes," NATS said.

While the overall number of flights at Heathrow is capped, "Pairwise has contributed to the average landing rate at peak times by over one movement per hour," according to NATS. "Heathrow has become Europe’s most punctual major airport so far this year."

Pairwise is a new way of calculating the safe minimum separation between aircraft. "Traditionally, the gap between arrivals has been based on six categories that consider an aircraft’s weight and the wake it creates as it flies," NATS said. "Pairwise uses the specific characteristics of each individual aircraft type, supporting air traffic controllers to safely reduce the separation between some aircraft pairs, thereby increasing the overall flow of traffic and reducing airborne holding."