No, an airliner did not almost break the sound barrier

Did an airliner on a flight to Europe from the United States almost break the sound barrier as news organizations are claiming today?

The British Airways flight reached ground speeds of up to 745 miles per hour, CNN reports. The sonic barrier, or the speed of sound, is broken at about 761 mph. For the sake of the discussion, let’s just ignore the fact that the speed of sound — Mach 1 — changes depending on circumstances.

“The plane was quite close to breaking the sound barrier,” The Inquisitr said.

If you paid attention in science class, you’ve probably already spotted the flaw in the story.

The airliner, helped along by a tailwind, wasn’t flying any faster than any other airliner usually does, so it didn’t come anywhere near breaking the sound barrier. If it had, it would have broken up from the stresses.

Consider this explanation from an airline captain:

The confusion arises between the understanding of ground speed and the plane’s speed. The ground speed is the speed at which an object travels relative to a fixed point on the Earth’s surface. The difference between ground speed and airspeed is caused by the influence of winds on the overall speed of the aircraft.

This is analogous to you walking at 2 mph along a walkalater (travelator) that is moving at 2 mph. Your actual movement towards your plane at the gate is pretty fast at 4 mph (2 + 2) but as far as you are concerned, you are still walking at 2 mph!

And speed and time are not the same thing.

  • jon
  • kevinfromminneapolis

    I didn’t grasp this until the walkway analogy.

  • davehoug

    Airliners are NOT designed for the stress involved. They first learned there was such an actual barrier when fighter pilots dove down fast and broke up when there were no enemy bullets or action.

    • >>Airliners are NOT designed for the stress involved.<<

      They're not?

      😉

      • davehoug

        OK, I stand corrected for that model, good one 🙂

  • davehoug

    The US bombers actually flew backwards over Japan. The head honchos didn’t believe the tales of those Crazy Winds over Japan until one took a flight himself and saw the ground going backward after the bomb bay doors were opened.

    Speed of the plane thru the air is waaay different than speed of the plane over land.

  • tboom

    Coming to scientific conclusions in this manner is why some still believe climate change isn’t happening.

  • Jack Ungerleider

    Most people who have taken long car trips have probably experienced a variation on this. A strong tail wind will increase your gas mileage at a given speed because the car isn’t working as hard. Of course a head wind will do just the opposite.