Australian air traffic services provider Airservices Australia is developing a number of new air traffic management initiatives designed to reduce aviation's footprint on the environment.

Initiatives in operation, at the trial phase or in planning include pre-tactical departure management, continous descent approaches, flexible tracks and "green approaches".

The Australian Greenhouse Office estimates that emissions from domestic aviation will remain at around 7% of total transport emissions over the next 10 years - or about six million tonnes of carbon dioxide. International aviation is estimated to have a similar impact. Improved ATM can play a role in reducing this output, says chief executive Greg Russell.

Airservices is using pre-tactical departure management at Sydney and Melbourne to reduce the environmental impact of delays by holding aircraft on the ground rather than in the air, Russell said at the recent Australian Airports Association Outlook 2007 conference. The service provider and its customer airlines are negotiating short delays in departure times in order to avoid delays in holding patterns. For example, a five minute delay on the ground can reduce CO2 emissions on a typical Melbourne-Sydney flight by more than 600kg (1,320lb), according to Russell.

Meanwhile, the service provider's continuous descent approach (CDA) trial - whereby an aircraft flies a continuous and uninterrupted descent at idle power from cruise altitude to the runway - is showing fuel savings as much as 400kg per arrival and more than a tonne of reduced CO2 emissions.

CDAs are often not possible in congested airspace and poor weather so the service provider is now working on tailored arrival and green approach procedures that combine advanced navigation capability, data link communications and time management to provide CDAs in all weather conditions.

Green approaches are still in the early planning stage and are "some way off", concedes Russell, as few aircraft are equipped with the necessary avionics. "The concept is very broad indeed nothing less than full control of air traffic flow in all four dimensions - latitude, longitude, altitude and time," he says.

En route, the service provider is further developing area navigation, allowing aircraft to fly optimum routes, while its implementation of automatic dependent surveillance-broadcast in upper airspace offers more optimum trajectories.

Meanwhile, the ATM long-range optimal flow tool (ALOFT) is reducing delays at Sydney by adjusting the cruising speed of aircraft en route. Airservices is looking to extend it to Melbourne early next year.

Flextracks, which are non-fixed air traffic routes that are optimised for the prevailing weather on a daily basis, are already being widely used between Australia and Asia and the Middle East by several carriers. Flextracks can lead to fuel savings of up to 8%, says Russell. The service provider is now examining the domestic application of Flextracks.

Airservices is also working with the University of New South Wales on development of the Air Traffic Operations and Management Simulator (ATOMS) which is a high fidelity fast simulation tool to explore advanced ATM concepts.

Source: Flight International