Passengers on board British Airways Flight 112, from New York’s Kennedy International Airport to Heathrow Airport outside London, received some good news early Thursday morning. The flight, which would normally take about six hours, would have arrived 50 minutes early.
Other eastbound flights over the Atlantic this week arrived ahead of schedule, up to an hour early in some cases, thanks to the jet stream blowing in their favor.
For example, a United flight that left Newark Liberty International Airport on Tuesday night arrived 58 minutes early at Charles de Gaulle Airport near Paris, a trip that typically takes about seven hours, according to FlightAwareA website that tracks air traffic.
Tuesday’s Emirates flight from Dallas-Fort Worth International Airport to Dubai in the United Arab Emirates was supposed to take 13 hours and 44 minutes. The plane landed 57 minutes early, according to FlightAware.
Here’s what you need to know about these early arrivals.
What is the jet stream?
A jet stream is a band of strong winds that blow from west to east in the upper levels of the atmosphere, or about 30,000 feet from Earth, according to the National Oceanic and Atmospheric Administration.
One way to understand how the jet stream affects flights is to think of a boat on the water, according to Jennifer Strozas, a meteorologist at the National Weather Service’s Aviation Weather Center.
“The atmosphere behaves very much like a fluid,” she said. “If the water is calm, the boat will stay still too. If the water has a strong current, it will naturally push the boat forward.”
When planes fly in a jet stream, strong winds can push the plane faster, Ms. Strozas said.
Commercial flights typically fly at a ground speed of about 570 mph, according to Richard Levy, an aviation consultant who used to fly commercial planes.
The jet stream over the Atlantic Ocean this week helped flights travel faster than their average speeds. For example, a British Airways flight from New York to London reached an airspeed of 734 miles per hour
Jet stream-assisted flights are not rare.
It’s common for jet streams to speed up flights heading from west to east, said Kevin Coleman, a professor of aviation and space science at Metropolitan State University in Denver.
In the summer, it is more common for flights to be affected by the jet stream when they are farther north. In winter, the jet stream can shift south, Mr. Coleman said.
This shift “could create a situation where that movement is given a boost,” he said.
Jet stream-assisted flights are not limited to those crossing the Atlantic Ocean. Mr. Levy said he was accustomed to the jet streams speeding things up when he was flying east over the Pacific Ocean.
Jet streams can also speed up domestic flights. The jet stream that was blowing over the United States in February 2019 helped eastbound flights Arrive well ahead of schedule.
Disorder can be a problem.
Experts said drafts are not always a blessing for pilots and travelers. Flying through the jet stream can cause turbulence in some cases.
To avoid turbulence problems, pilots sometimes travel at a lower speed, Levy said. Flying through a jet stream can be like driving on a bumpy road, he said.
The faster someone drives on a bumpy road, “the worse it is for the car and for you,” Mr. Levy said, adding that in these situations it is better to slow down.
“This is exactly what we do with unrest,” he said. “We’re bringing him back.”
Mr. Coleman said pilots encounter turbulence most often when flying in and out of the jet stream.
“This transition zone is certainly going to have potential for disruption,” Mr. Coleman said. “But just because it’s in it doesn’t mean it’s dangerous.”
However, Mr Levy said turbulence could be a problem on any flight, whether jet stream or non-jet stream. Pilots remind passengers to keep their seat belts fastened to be safe, and to stay in touch with air traffic controllers who can alert them about possible turbulence.
The return trip may not be so quick.
Strong easterly winds can help aircraft traveling from west to east, but the same current can have the opposite effect on an aircraft heading west.
“The opposite is also true,” Ms. Strozas said. “If it flies into strong winds, that will effectively slow it down, as will trying to paddle downstream.”
Mr. Levy said it is possible to avoid flying west in a jet stream, because it slows you down; B, you’ll burn gas like crazy without seeing anything; and C, disorder. Sometimes, this is unavoidable, given the itinerary, he said.
On a westbound flight from London to New York City, the jet stream can largely be avoided by flying north over Greenland, Levy said.
“We don’t go anywhere near it,” he said.
Early arrival is not always better.
Arriving at the destination ahead of schedule is usually good news.
“I’d like to get to O’Hare in Chicago early,” Mr. Coleman said.
He added: “But guess what next? “There’s no gate for you” if you land early.
Potential problem: Passengers may find themselves sitting in the plane, stuck on the floor while the crew waits at the gate so everyone can get off the plane.
Waiting for the gate was a less common inconvenience for travelers at some airports in Europe, which have dedicated gates for specific airlines, Mr. Levy said. Flight tracking computers also help avoid delays on the ground.
“As soon as the wheels are off the ground, the computer immediately knows your ride time,” he said.
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