Out of most important changes for global travel involves the jet stream, the powerful upper- atmosphere winds that aircraft must navigate. Jet stream patterns influence flight routes, travel time and airline fuel economy because long-distance air corridors are designed to take maximum advantage of prevailing weather patterns, which give a tailwind to eastbound flights and a headwind to westbound ones.
Jet stream winds at high altitudes are getting more intense, researchers say, which not only makes flights bumpier but also potentially affects travel times. Dr. Williams pointed out that from Jan. 8 to Jan. 12, 2015, a strong jet stream forced some flights from Europe to the United States to make unscheduled refueling stops on the East Coast before reaching their final destinations, even though they should have had enough fuel to make it all the way.
On the other hand, flights in the other direction during that time with the jet stream at their backs made the trip faster than usual. In fact, a British Airways flight broke the conventional passenger jet trans-Atlantic speed record, making the trip in 5 hours and 16 minutes, Dr. Williams pointed out. Only the super-sonic Concord has done it faster.
It may seem counterintuitive, but the gains flying east aren't enough to offset the losses flying west. Dr. Williams has researched this, too, and he found that fighting the headwind slowed a flight more than flying with a stronger tailwind sped it up. This would eventually produce longer round-trip flight times, and higher fuel consumption.
Jet stream winds at high altitudes are getting more intense, researchers say, which not only makes flights bumpier but also potentially affects travel times. Dr. Williams pointed out that from Jan. 8 to Jan. 12, 2015, a strong jet stream forced some flights from Europe to the United States to make unscheduled refueling stops on the East Coast before reaching their final destinations, even though they should have had enough fuel to make it all the way.
On the other hand, flights in the other direction during that time with the jet stream at their backs made the trip faster than usual. In fact, a British Airways flight broke the conventional passenger jet trans-Atlantic speed record, making the trip in 5 hours and 16 minutes, Dr. Williams pointed out. Only the super-sonic Concord has done it faster.
It may seem counterintuitive, but the gains flying east aren't enough to offset the losses flying west. Dr. Williams has researched this, too, and he found that fighting the headwind slowed a flight more than flying with a stronger tailwind sped it up. This would eventually produce longer round-trip flight times, and higher fuel consumption.
Transcontinental flights over the United States may in the future have to make midroute stops more frequently, too. On a calm-weather day, a nonstop flight from New York to Los Angles already approaches the maximum range of a Boeing 737 or Airbus A320, common aircraft on that route and others like it.
Airlines, of course, could also use jets with longer ranges on such routes. But as Dr. Williams points out, “It might be preferential to break it up into two shorter segments.”
Dr. Williams published another paper, in May, which suggested that incidents of turbulence could increase and become more severe.
He said a stronger jet stream resulted in less stable air, so turbulence could become more likely even if there are no storms, something that is known as “clear air” turbulence. Eastbound flights would be more likely to be affected because they tend to fly more directly in the jet stream to take advantage of the tailwind.
Although modern aircraft are better able to respond to turbulence than their predecessors, passengers may still notice bumpier rides in the future.
Since the 1980s, Dr. Williams said, “the number of serious injuries being caused by turbulence has a clear upward trend.”
Manufacturers are working to make aircraft more adaptable to bumpy rides, and to better predict and detect clear-air turbulence.
Airlines, of course, could also use jets with longer ranges on such routes. But as Dr. Williams points out, “It might be preferential to break it up into two shorter segments.”
Dr. Williams published another paper, in May, which suggested that incidents of turbulence could increase and become more severe.
He said a stronger jet stream resulted in less stable air, so turbulence could become more likely even if there are no storms, something that is known as “clear air” turbulence. Eastbound flights would be more likely to be affected because they tend to fly more directly in the jet stream to take advantage of the tailwind.
Although modern aircraft are better able to respond to turbulence than their predecessors, passengers may still notice bumpier rides in the future.
Since the 1980s, Dr. Williams said, “the number of serious injuries being caused by turbulence has a clear upward trend.”
Manufacturers are working to make aircraft more adaptable to bumpy rides, and to better predict and detect clear-air turbulence.
