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Transportation

Record-Breaking Jet Stream Accelerates Air Travel, Flight Clocks In At 801 MPH (cbsnews.com) 99

pgmrdlm quotes CBS News: On Monday night, the river of air 35,000 feet above the New York City area, known as the jet stream, clocked in at a blazing 231 mph. This is the fastest jet stream on record since 1957 for the National Weather Service in Upton, New York — breaking the old record of 223 mph, according to NWS forecaster Carlie Buccola. This wind provided a turbo boost to commercial passenger planes along for the ride. With the help of this rapid tailwind, Virgin Atlantic Flight 8 from Los Angeles to London hit what could be a record high speed for a Boeing 787: 801 mph over Pennsylvania at 9:20 p.m. Monday night...

"The typical cruising speed of the Dreamliner is 561 mph," CBS News transportation correspondent Kris Van Cleave points out. "The past record for the 787 is 776 mph set in January 2017 by a Norwegian 787-9 flying from JFK to London Gatwick. That flight set a record for the fastest subsonic transatlantic commercial airline flight -- 5 hours and 13 minutes, thanks to a 202 mph tailwind."

FlightAware, a global aviation data services company, reminds CBS that even a 100 mph increase in the jet stream can shorten a flight by an hour.
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Record-Breaking Jet Stream Accelerates Air Travel, Flight Clocks In At 801 MPH

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  • Idle speculation (Score:4, Interesting)

    by 93 Escort Wagon ( 326346 ) on Saturday February 23, 2019 @04:50PM (#58170138)

    Of course, that could mean flights going the other direction will be *delayed* by an hour or more - either because they’re heading into the strong stream or because of the extra distance routing around it.

    I wonder if flights being an hour early creates headaches for air traffic control and gate management at the destination? It’s great for the passengers though.

    • Re:Idle speculation (Score:4, Informative)

      by supernova87a ( 532540 ) <kepler1@@@hotmail...com> on Saturday February 23, 2019 @05:04PM (#58170178)
      Airline planners would likely have the routes deviate in the opposite direction to not be flying in the strongest part of the jetstream, so it's not an equal advantage / disadvantage for both directions.

      You may be interested to see the jetstream maps [sfsu.edu] for how wide it typically is: generally several hundred miles wide
      • Some animated maps of North Atlantic jetstream forecasts.
        https://www.netweather.tv/char... [netweather.tv]
        I assume airlines already use these to take different routes but I do not know whether they do.

        • by mrvan ( 973822 )

          You wonder whether a multi-billion dollar industry would use a simple online tool to optimize their routes to reduce their 2 biggest costs (fuel and aircraft+crew hours) and service their customers better at the same time? :D

      • Can someone translate the units used from furlongs-per-fortnight or whatever into something meaningful like km/h?
    • by Solandri ( 704621 ) on Saturday February 23, 2019 @05:04PM (#58170182)
      Flights in the other direction can usually be re-routed to a different altitude or route where the jet stream is not as strong. Likewise flights in the same direction as the jet stream can be preferentially routed to take advantage of it it's strong.

      I was on a flight from Asia to the U.S. which benefited from a particularly strong jet stream and arrived 3 hours early (11 hours instead of 14 hours). For that, we were punished by having to stay in the plane at the gate for nearly 2 hours, since the Customs and Immigration employees hadn't yet arrived for work that morning to process arrivals. I would imagine it's the same for domestic flights if there's insufficient room at the gates. The plane would probably have to stay somewhere on the tarmac until a gate opened up. I suppose that objectively it's slightly better for the passengers (same amount of time aboard the plane, but it's quieter). But subjectively, it's rather frustrating knowing that you're already at the destination, but are prohibited from deplaning by logistics.
      • I had a similar experience Narita to LAX. We arrived two hours early, didnâ(TM)t sit in the plane, but had to wait in line for customs to show.

      • by dcw3 ( 649211 )

        Ridiculous. This is a common occurrence that they should have planned for. I lived in Korea for many years, and flights to the US often pick up jet stream winds.

    • by dcw3 ( 649211 )

      It's the same idea with the Gulf stream...ships don't sail against it across the Atlantic...they go around it.

      • It's the same idea with the Gulf stream...ships don't sail against it across the Atlantic...they go around it.

        ..and since you will be sailing by the west coast of Africa in your way to Connecticut....

        • by dcw3 ( 649211 )

          It's the same idea with the Gulf stream...ships don't sail against it across the Atlantic...they go around it.

          ..and since you will be sailing by the west coast of Africa in your way to Connecticut....

          Often, the most direct route is not the quickest.

  • This article didn't butcher it too badly. But still there's a layer of education opportunity that was missed.

    It wouldn't take more than 2 sentences to include an explanation about ground speed versus air speed. Not even talking about the differences in airspeed at different altitudes and densities, mach, etc. But I guess even that is too much for our technical details-allergic media.
    • It wouldn't take more than 2 sentences to include an explanation about ground speed versus air speed. Not even talking about the differences in airspeed at different altitudes and densities, mach, etc. But I guess even that is too much for our technical details-allergic media.

      It never occurred to me that anyone would need that explanation. Everyone knows that a tailwind makes you go faster and a headwind makes you go slower. It's utterly obvious that if your engines make you go X mph, and you have a Y mph tailwind, you're going X + Y mph.

      Maybe the reporter also thought it was too obvious to waste words on.

  • So much for the hypothesis that AGW would weaken the jet stream.
    • by Anonymous Coward

      Stop trolling. You're conflating weather and climate. This is an extreme event, whereas the weakening of the jet stream and Arctic amplification is about long term statistics. One extreme event neither proves nor disproved AGW or related hypotheses.

    • So much for the hypothesis that AGW would weaken the jet stream.

      If glacial melting persists apace, the conveyor will shut down, and then the jet stream will follow. You're just off schedule.

  • Faster Than Sound! (Score:4, Interesting)

    by crow ( 16139 ) on Saturday February 23, 2019 @05:57PM (#58170356) Homepage Journal

    That's significantly faster than the speed of sound! Sound travels at about 660 mph at a 787's cruising altitude. Of course, sound travels through the air, so the plane wasn't actually breaking the sound barrier, as the air speed was below that, so it wasn't really hitting Mach 1, but I suppose if the plane were to suddenly dive out of the jet stream into relatively still air, it would have done so; I wonder how well it would have handled the stress?

    • by dcw3 ( 649211 )

      The speed of sound is not a constant.
      https://en.wikipedia.org/wiki/... [wikipedia.org]
      https://en.wikipedia.org/wiki/... [wikipedia.org]

      • by crow ( 16139 )

        Yes. That was clearly implied by several parts of what I wrote. When I mentioned the speed of sound, I included the phrase "at a 787's cruising altitude." I also was quite clear on the speed being relative to the air speed, and the big deal was the plane's ground speed.

        • by dcw3 ( 649211 )

          Maybe implied, but I'd say lacking in clarity. Not a criticism, and no need to be defensive, I just added to what you wrote.

    • by Kjella ( 173770 )

      so it wasn't really hitting Mach 1, but I suppose if the plane were to suddenly dive out of the jet stream into relatively still air, it would have done so; I wonder how well it would have handled the stress?

      Well my impression is that it's more a problem for everybody else, like the first supersonic flights were a success it's not like they ran into a brick wall and had to redo the designs. Maybe it'd eat into the lifespan but my guess is it'd be fine.

    • I wonder how well it would have handled the stress?

      Not well. Certainly the passengers would not have enjoyed the sudden deceleration. As far as the plane, neither the flight controls nor the engines are designed to handle a supersonic airstream. At the very least you would probably get a compressor stall on all engines, which would not do anything good.

      It's a pretty unlikely scenario though .... it's not like there's a sharp line with the wind on one side moving at 200 mph and zero movement on the other side.

    • by tlhIngan ( 30335 )

      That's significantly faster than the speed of sound! Sound travels at about 660 mph at a 787's cruising altitude. Of course, sound travels through the air, so the plane wasn't actually breaking the sound barrier, as the air speed was below that, so it wasn't really hitting Mach 1, but I suppose if the plane were to suddenly dive out of the jet stream into relatively still air, it would have done so; I wonder how well it would have handled the stress?

      Except that isn't airspeed, it's ground speed. Airspeed is

  • To put that in perspective: 801MPH is Mach 1.044. (The speed of sound is 767.27 mph).

    Its relative speed to the ground would be faster than the speed of sound
    • Re:Mach 1.044 (Score:5, Informative)

      by tsqr ( 808554 ) on Saturday February 23, 2019 @08:06PM (#58170704)

      Mach number is the ratio of the speed of an object thorough an air mass (aka, airspeed) to the speed of sound through the same air mass. The speed of sound you cite is the speed of sound in dry air at 20 C. Since the airliner was flying at 35,000 feet, or 10.7 km, we can assume (using the standard lapse rate of 6.5 C per kilometer) a much lower temperature of approximately -50 C, and thus a significantly lower speed of sound.

      Having said all that, it is meaningless to speak of Mach in relation to ground speed. Note the quote from TFS: "The past record for the 787 is 776 mph set in January 2017 by a Norwegian 787-9 flying from JFK to London Gatwick. That flight set a record for the fastest subsonic transatlantic commercial airline flight -- 5 hours and 13 minutes, thanks to a 202 mph tailwind."

  • Well sure, but what about the reverse leg of the trip?

  • Last week, I tracked my wife on a flight from LAX->IAD on a 737-900 at ~715mph. Yes, mph is what Flightaware showed...not knots. The "planned" speed was somewhere in the mid-500s. Her flight had taken off nearly half an hour late, and arrived well ahead of schedule.

    As a former (stopped years ago) Cessna pilot, I once flew from Korea to Japan. Normal airspeed in the 172 is around 110 knots, and with a 70 knot smooth tailwind, we arrived over an hour ahead of plan.

    • Do you know what the flight instruments show as speed? Since the pitot tube uses airflow to measure speed, I assume it should only measure the relative speed which shd be say mid-500s and not the absolute (ground speed) which is 715 mph. I guess lot of stall crashes are due to wrong relative speed measurement (hence a gps solution may not help)
      • by dcw3 ( 649211 )

        It's called an Air Speed Indicator. We didn't have GPS back when I flew, but speed isn't your first warning of a stall. Typically, the nose will fall over, and your stall warning horn will start blaring at you. Recovery (at least in small craft) is easy, and learned very early in flight training.

        • Recovery (at least in small craft) is easy

          I'm guessing that's along the lines of "Point the nose downward," correct? I've always kinda wanted to be a pilot, but cost and physical disabilities (hearing) got in the way. But, just in case I'm ever on a commercial flight and both pilots conk out and I'm the last line of defense against a flaming fireball into the ground, I'd like to have at least an idea how to recover from a stall.

          • by dcw3 ( 649211 )

            The nose will go over on its own. Apply full power...full opposite rudder if it's starting to spin. Once you have air speed back in the green, level the nose, and you're pretty much done.

            I was fortunate to work at an Air Base back in the late 80s where it cost $250 for a block of 10 hours in the Cessna 152s, or a bit more for the 172. If you needed an instructor pilot, that was another $11/hr. I spent around $3k before I was able to test...mostly because we had to wait on the elevator to come from Okina

  • Buh Metric anyone? (Score:4, Insightful)

    by Billly Gates ( 198444 ) on Saturday February 23, 2019 @10:30PM (#58171102) Journal

    I and the world have no idea how fast or how high up that is. Scientist should be using the Metric system like everyone else which makes it easier to understand and do calculations with.

    • In aviation -- almost everywhere -- feet is used for elevation, miles are used for distance, and knots are used for speed.

      • Depends what aviation. Paragliding is pretty much metric all worlds around ('muricans don't fly that much, Brittons don't fly that much in UK). Airspace zones are computed in advance and either avoided or ignored by idiots

  • by roc97007 ( 608802 ) on Saturday February 23, 2019 @10:47PM (#58171140) Journal

    Wait, didn't I see this somewhere before [wikipedia.org]?

  • NYC ?? (Score:4, Interesting)

    by Tom ( 822 ) on Sunday February 24, 2019 @02:56AM (#58171644) Homepage Journal

    the river of air 35,000 feet above the New York City area, known as the jet stream

    That's a way to describe a planet-circling phenomenon [merrittcar...phic.co.uk], if you are one of those morons whose map of the world has written "here be dragons" on everything outside the USA.

    It's not a way to talk to an educated audience like /.ers who know, many from first-hand experience, that places outside the three locations Hollywood places movies in actually do exist.

    Especially in a story that doesn't make sense unless you understand the actual reach of the jet stream.

  • -FlightAware, a global aviation data services company, reminds CBS that even a 100 mph increase in the jet stream can shorten a flight by an hour.-

    Lets take this apart.
    FilghtAware 'reminds' CBS. This denotatively means that CBS previously knew this. Can you even remind corporate knowledge?
    'even a 100 mph increase in the jet stream' really downplays the significance of what sounds to me to be a pretty significant number. In the article they say it hit a max recorded speed of 231 mph, how can 44% of the hig

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