Swedish green flight initiative comes to the end but promises greater future efficiencies to reduce aircraft emissions
Green approach on flight simulator at Oxford Aviation Academy
Tue 22 May 2012 – Next week sees the conclusion of a major six-month Swedish project to trial green gate-to-gate flights between Sweden’s two biggest airports, Gothenburg Landvetter and Stockholm Arlanda. The Green Connection partnership will have involved around 100 SAS flights since the first on 15 December 2011 and the last on May 31. Although green approaches involving pilots gliding with engines at idle from cruising altitude until the very last stage have been taking place at Arlanda since 2009, a key advance of the Green Connection trials is the use of a new arrival procedure for runway 26 first introduced in 2010. Through the latest GPS-based RNP-AR technology, the curved approach path has been shortened by around 11 nautical miles, over 20 kilometres, and is designed to avoid noise sensitive areas. Depending on the direction of the flight’s arrival, an average of 100kg or 164kg of CO2 emissions have been saved as a result.
As well as SAS, those taking part in the project include LFV, Sweden’s air navigation service provider, GE, Rockwell Collins and state-owned airport operator Swedavia, with flight simulation input from Oxford Aviation Academy. LFV designed and implemented the arrival procedure used in Green Connection.
“LFV has been working for many years to make our airspace more efficient – everything from shortening flight paths to improving flight timing,” said its Director-General, Thomas Allard, at a green flight demonstration at Oxford Aviation Academy. “The results of Green Connection demonstrate what the aviation industry can achieve when all actors cooperate towards a common goal. Implemented on a large scale, this can mean a significant reduction of greenhouse gas emissions.”
As part of the trials, the departing plane from Landvetter is allowed to climb to cruising altitude as quickly as the aircraft type allows, after which the plane takes the shortest possible route at optimal speed to Arlanda. During the flight the plane constantly communicates its anticipated flight path in four dimensions: longitude, latitude, altitude and time. This information, supplied by the flight management system (FMS), is analysed and compared against the actual flight path, enabling improvements to flight predictability and also to facilitate controlled time of arrivals, enabling the aircraft to fly optimum RNP-AR routes (Required Navigation Performance-Authorization Required).
The TrueCourse FMS used by SAS Boeing 737 NG aircraft during the trials was provided by project partner GE Aviation, which also developed the Preferred Business Trajectory Manager software that allows airlines to review and develop flight procedures as well as plan the four-dimensional trajectory the FMS will fly from take-off to touchdown.
According to Torborg Chetkovich, Group CEO of Swedavia, full utilisation of the latest navigation technology could annually shorten flight paths across the operator’s airports by a distance corresponding to 25 around-the-world flights.
Stockholm Arlanda has approximately 100,000 landings per year. When the new RNP technology can be fully implemented to all runways, even during peak hours, and when all aircraft have the suitable technology installed, around 25,000 flights would have their routes significantly shortened, says Swedavia. With an average reduction of 130kg of CO2 per RNP approach, the savings per year would be roughly 3,250 tonnes.
SAS Group CEO Rickard Gustafson described the Green Connection project as major step forward in making Swedish airspace more efficient, allowing the airline to improve punctuality and lower its emissions.
“Our goal is to reduce emissions by 20% by 2015 over 2005 levels, traffic growth included,” he said. “Along with newer, more efficient aircraft, improved energy efficiency in daily operations and using a blend of renewable aviation fuel, the development in this area is extremely vital to the realisation of our sustainability goal.”
The project has been partially financed by SESAR (Single European Sky ATM Research) and is part of the AIRE (Atlantic Interoperability Initiative to Reduce Emissions) transatlantic collaboration programme .