Airbus' New Navigation System to Reduce Fuel Consumption on Oceanic Flights

An airline's bottom line is tied pretty much to how efficient its fleet of airplanes operated.

As fuel prices skyrocketing, jet fuel becomes such a huge expenditure in an airline's balance sheet, that it can no longer ignore. Airlines are scrambling to look into different ways to minimize the impact caused by high fuel cost. Newer lighter aircrafts with fuel-efficient engines are put into service replacing older heavy aircrafts that burned more fuel. Small lighter aircrafts are used whenever situation warranted.

Aircraft manufacturers are no different. Being light and being fuel efficient are the main design goals, that they try to achieve in all of their products.

When it comes to vast open waters, such as the Atlantic Ocean and Pacific Ocean, the range of conventional land-based radars is inadequate and their effectiveness (as an air traffic control tool) diminishes. Vast oceans also render short-range land-based Very High Frequency (VHF) air-to-ground communication useless. The widely-used land-based VHF Omnidirectional Range navigation system (VOR), with its network of transmitting stations, is a concept that simply does not work when it comes to opened waters.

Air navigation has come a long way from the time when sextants were used in the cockpit to guide airplanes traveling over opened waters. To make ocean crossing possible, ships were stationed at four spots in the North Atlantic Ocean at one time to serve as floating Non-directional beacons (NDB). Today, the advance of Global Positioning System (GPS) has changed all that. Signals from a network of geosynchronous satellites provide an accurate and inexpensive means to navigation in general.

A very different air traffic control system is therefore put in place to address the hurdles that are associated with vast opened waters. In oceanic-going flights, air-to-ground communication is conducted using long-ranged High Frequency Single Side Band (HF/SSB) equipment.

Instead of using land-based VORs and predefined routes, flight plans are defined using the earth's coordinates and predefined fixes on over-water segments. To work around weather, daily ocean-crossing tracks (corridor of neatly arranged airways), e.g. the North Atlantic Tracks and the Pacific Organized Track System (PACOTS), are jointly published for heavily-traveled routes by aviation authorities of different countries.

Even with today's advance in avionics, pilots are still required to project and report their positions in certain oceanic sectors. Without the help of land-based radars, airplanes are kept in safe distance from one another by air traffic controllers, who gather aircraft position data from pilots manually and analyze their reports through other means. Aside from visual contact, pilots have few clues (mainly from the air-to-ground communication channels) about other aircrafts in their close vicinity.

Last month, Airbus tested a new navigation procedure called CRISTAL ITP (in-trail procedures), building on satellite-navigation-based Automatic Dependent Surveillance Broadcast (ADS-B) technology to give pilots a clear view of their immediate surroundings during oceanic crossings. Airbus claims the new procedure, if implemented, will cut fuel consumption by allowing airplanes to change cruising altitude safely and to fly at their optimal speed and altitude.

Airbus conducted its recent test flight over the Icelandic airspace, using two aircrafts: a Scandinavian Airlines Airbus A330 and an ADS-B-equipped A340 flying in close proximity. The A330 was equipped with the 'ADS-B Out', a GPS-derived, position-broadcasting technology which already certified for all modern Airbus jets.

As part of this test, the Airbus A330 was cruising at a fixed altitude and broadcasting its position and altitude continuously to be received by nearby stations. The Airbus A340-600 test aircraft was outfitted with the new 'ADS-B In' technology allowing pilots of the aircraft to see the positions and altitudes of all other aircraft in the area. In addition to flight data received from the Airbus A330, the test aircraft received Traffic Information Services—Broadcast (TIS-B) data on aircraft positions and altitudes transmitted by nearby air traffic control facilities. With new flight data at hand, the pilots of the Airbus A340 test aircraft could assess the separation requirements in real time and requested clearance for altitude changes when the two aircrafts were at a safe distance from one another.

Airbus estimates that a wide-body jet could cut fuel consumption by 374 pounds on each Atlantic crossing if it can cruise and change altitude to reach maximum fuel efficiency. With 700 daily flights crossing the Atlantic Ocean alone, savings on fuel consumption can be enormous. If all goes well, Airbus plans to have the CRISTAL ITP procedure up and running over the Atlantic Ocean no later than 2010.

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