Improving efficiency of flight paths naturally results in less CO2 emissions. To achieve this, a partnership in the Pacific Northwest of the USA has packaged together a set of new technologies to deliver fuel, time and CO2 savings.

Dubbed "Greener Skies over Seattle," the project brings together several satellite-based flight guidance technologies and new flight procedures to allow aircraft to descend more efficiently into Seattle-Tacoma Airport. This method cuts down on fuel burn, as the engines are left on low or idle power settings more often during the approach.

The procedures which have been implemented combine a set of different innovations: optimised profile descents (where the aircraft essentially glides in idle to the runway threshold); area navigation (RNAV) arrivals (which are GPS-guided arrivals); and required navigation performance (RNP) approaches (which takes RNAV to an additional level of precision).

Alaska Airlines reports that its use of the Greener Skies approach has resulted in an average nine minutes less flying time per flight and has cut 14,350 tonnes of CO2 per year. Whilst Alaska Airlines has led the way on this project, the procedures are now being used by any properly-equipped airline.

In addition to increasing the efficiency of flights in and out of the airport, Greener Skies provides opportunities for increased capacity by reducing standard separation, as the aircraft are able to be tracked precisely.

Taken on as a Next Generation project by the United States’ Federal Aviation Administration in 2010, Greener Skies was fully implemented in April 2015. The ultimate aim of the FAA is to use the reduced aircraft separation standards at 12 other airports across the United States that have similar runway configurations to Seattle-Tacoma and there is, of course, potential for the system to be repeated at airports across the world.