A trial to cut down on the amount of time aircraft spend circling in holding stacks at London's Heathrow Airport has shown positive results.
The initiative, which has been led by air traffic services provider NATS, as part of the UK-Ireland FAB and in collaboration with FABEC and Heathrow Airport, aims at bringing down average holding times by a quarter from the current time of eight minutes.
NATS has recorded a decrease of up to a minute in holding times since April 2014 for flights influenced by the trials. This reduction helped in saving airlines close to £1m (€1.25m) in fuel and 5,000t of CO².
The trials entered its third phase in September 2014, when the minimum stack delay threshold was seen to be reduced from nine minutes to seven and the maximum speed reduction raised to 0.04 Mach from 0.03 Mach.
The trials also led to a reduction in noise for communities underneath the stacks.
As a part of the trials, controllers in the UK, France, Ireland and the Netherlands have been working together to slow aircraft down up to 350 miles away from London.
NATS managing director operations Martin Rolfe said: "Taking 60 seconds out of holding for trial influenced aircraft may not seem a lot, but it is a significant achievement and equates to serious savings for our airline customers while proving that this kind of cross-border cooperation can reap real benefits.
"The next steps involve us taking what we've learnt so far and improving and refining our procedures for even greater results."
Heathrow Airport airside director Derek Provan said: "This trial is a definitive step in the right direction towards quieter and more sustainable airline operations. We welcome the efforts NATS has made, and for working with us to make Heathrow a better neighbour to local residents."
Image: Heathrow's holding stacks - three shown here in orange - provide a continuous stream of arriving air traffic. Photo: courtesy of NATS.