United Airlines recently flew a Boeing 777 across the Atlantic more efficiently by giving the pilots more leeway:
During a transatlantic flight, an airliner typically is assigned a fairly limited track of airspace to follow to its destination. It’s like flying through a narrow pipeline. On United’s demonstration flight, pilots were assigned a flexible track — in essence, a bigger pipeline. The wider swath allowed the pilots to wander a bit, going where the best winds will help push the plane along. Or, in the case of a headwind, minimize the resistance.
Airlines already know, based upon forecasts and information from other aircraft, where to find the best winds. But pilots are forced to follow the narrow track over the ocean because vast swaths of the sea are not covered by radar. Because air traffic controllers obviously cannot see the airplanes, pilots must follow preassigned paths to avoid other aircraft.
New technology under development for the next generation of air traffic control allows airliners to see each other to maintain safe distances between aircraft. One of the key components to this new ability is the use of a system known as ADS-B.
Automatic dependent surveillance-broadcast uses GPS so an aircraft can broadcast its own position via a transmitter to other aircraft, as well as to air traffic controllers on the ground. In parts of the world where radar coverage is not available, this allows pilots and controllers to keep track of the positions of aircraft. United’s Joe Burns says when the technology is used throughout the airline fleets the flexible track flying used during the demonstration flight could be used on a much wider scale.
“The next phase of this project is obviously to go back and see how do we let everybody take advantage of this all of the time” Burns says.
It’s interesting, in the first era of air traffic control, in the 1930s, there was no radar coverage, and the pilot had to inform the controller of his location, which he knew precisely only when passing over a radio marker beacon or radio-range station. With the coming of radar, the controller often knew where the airplane was as precisely (sometimes, more precisely) than the pilot did, although reversion to non-radar modes was/is always possible in the event of equipment failure or coverage loss due to terrain. With the coming of GPS, the pilot knows his position independent of ground-based navigation facilities. And with ADS-B, the airplane now informs the controller (and other aircraft) of its own location. Full circle.