Operational improvements

Efficiencies gained through operational improvements can make a big difference. At every step of a plane’s operations there are opportunities to reduce fuel burn and consequently, emissions.

Airlines are saving fuel through more efficient procedures and weight reduction measures. These can range from ensuring the plane’s engines are clean to developing and using new arrivals procedures. Some airlines taxi to the runway using just one engine instead of two.

On the ground

When parked at airport gates, aircraft must be powered to provide air conditioning and electricity and also to start the engines. Aircraft are equipped with a small generator in the tail called an auxiliary power unit (APU). A large number of airports are now equipping their gates with fixed electrical ground power and pre-conditioned air, allowing pilots to switch off the APU, saving fuel and noise while on the ground.

Airports are also working to make ground service equipment (baggage loading devices, catering trucks, passenger buses) more energy efficient, using natural gas or electricity.

Departure

As aircraft taxi from the gate to the runway, there are techniques in operation, such as single-engine taxiing, or in development, such as self-driving devices, which enable aircraft to reach the runway without using full engine power.

Airports, airlines and air navigation service providers are also working together on so-called ‘green departures’ where aircraft can take off and climb at a steady rate to reach the most efficient phase of flight – the cruise – faster.

Cruise

Despite their size, aircraft still burn less fuel when they have less weight on board, so airlines are finding ways to reduce the weight of a vast array of items carried – everything from food service trolleys, to seats and carpets, to loading just the right amount of water for each flight, rather than filling the tanks each time. This results in significant savings.

Airlines and air traffic controllers are also working together to take advantage of weather conditions at high altitudes. Pilots and flight planners have been studying wind patterns prior to departure and routing the aircraft along strong wind streams. Despite sometimes flying a much greater distance, use of windstreams has reduced both flight time and emissions. Flexible routing is also now taking place, particularly on long routes in uncrowded airspace, but new surveillance technology much like GPS systems will enable it to be used on more crowded routes.

Arrival

Traditionally, flights have descended from cruising to landing in several steps, descending from one altitude to the next then ‘levelling out’ by powering up the engines. New technology allows much more accurate surveillance of where each aircraft is located, and therefore provides a more comprehensive picture of the traffic environment.

This has led to a new technique – continuous descent operations – which allows aircraft to almost ‘glide’ into the airport, with engines at a very low setting. This not only saves fuel but also reduces noise impact on surrounding communities. It is being used more and more now around the world, depending on weather and traffic conditions.

Carefully tailored techniques, which take advantage of sophisticated navigation technologies, are also being developed to determine the most appropriate flightpaths into airports, specifically those with difficult runway approaches – either in mountainous areas or to avoid flying over communities. These approach techniques can save millions of tonnes of fuel and CO2, as well as reducing the impact of aircraft noise around airports.