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Key points
- Turbulent occurs because fast-moving air is mixing with slow-moving air.
- Because unexpected turbulence is possible, passengers are told to wear their seat belts.
- Now and then, passengers who refuse to comply are injured in turbulent skies.
- The media rarely reports that the injured passengers were not wearing their seat belts as instructed.
Aviation news is unreliable for two reasons. Since few reporters are pilots, most do not have enough aviation expertise to know whether what they write is accurate or not. Then there is the matter of clickbait.
Clickbait-style articles, intended to garner eyes at all costs, in this case by exaggerating the dangers of flying, have little effect on those who do not fear flying. Their high-level thinking puts the news into perspective, even if an initial alarm is sounded in their mind. Even if something shocking happened as reported, it is unlikely to happen to them. The matter is dismissed.
Not so with fearful fliers. When something shocking causes alarm, their parasympathetic nervous system does not kick in. They remain in a state of alarm.
When we feel alarmed, of course we need to check out what is going on. But alarm, because it is intense, disables our high-level thinking. In the case of a fearful flier, sensationalized news causes long-lasting alarm which makes it impossible for them to recognize they are being victimized by click-bait. Their belief that flying is dangerous is reinforced.
A recent clickbait subject was a Lufthansa flight that departed Austin, Texas for Frankfurt, Germany on May 1st. The flight ran into unexpected turbulence over Tennessee and diverted to Washington Dulles airport so seven passengers could receive medical attention. A blog that claimed the plane fell thousands of feet went viral. I received a barrage of emails from clients who were alarmed by what they read. Here is an example. "I’m freaking out a bit about the Lufthansa flight that had severe turbulence. That’s such a good airline and it’s a normal flight. I’m flying next week and was feeling good but now I’m not."
Did The Lufthansa Flight Drop?
Another person wrote, "Matthew McConaughey's wife said the flight dropped 4000 feet. I'm a veteran of your program and know that turbulence doesn't involve huge drops in altitude. Still, I'm curious what you think happened and why, based on the flight log (visible at FlightAware) the plane's altitude changed so dramatically."
I replied that the plane did not drop 4000 feet. The change in altitude was deliberate. If I were flying a plane and ran into heavy turbulence, I would ask Air Traffic Control for a lower altitude. Once cleared, I would descend to get out of the turbulence. An altitude change usually gets the plane out of the rough air. Going to lower altitude rather than a higher altitude is the better strategy because a plane can descend more rapidly than it can climb.
The Truth About Turbulence
There is turbulence someplace in the world all the time. It is a natural phenomenon. Air is spun up away from the planet due to the earth's rotation. The upward momentum is greater at the equator than at any other point on the globe. The linear speed of the earth at the equator is approximately 1000 MPH (because the earth rotates once every 24 hours, and the circumference of the earth at the equator is 24,901 miles). As the planet spins, air is spun upward by centrifugal force until it loses its upward momentum. It can't come back down because more air is always being spun upward. Thus, air that has lost its upward momentum is shoved aside, which means some of it goes north, and some of it goes south. As it does, it is still moving at the speed imparted to it by the equator. This means it is moving faster than the earth below because the circumference of the earth is less north and south of the equator. The farther north (or south) the equator-speed air migrates, the faster it overtakes the earth below.
Away from the equator, if we look up and study the clouds high above us, we can see they are moving from west to east. If we could measure the speed at which equator-speed air is carrying the clouds along with it, we might discover the speed is around 200 MPH.
Yet, where we stand on the ground, air is moving only slightly. Between where we are and 35,000 feel above us, there is a lot of change in the speed of the air. If we were in a hot air balloon, as we ascend, our speed across the ground - in a generally easterly direction - would increase. The higher we go, the faster we overtake the earth below us. We feel no wind going by us because our balloon is going at the same speed as the wind. As we ascend, if the speed of the air increases gradually, we would have a smooth ride. But, if we ascend into air that is moving considerably faster, the fast-moving air would mix with the slow-moving air. This mixing causes turbulence. Even so, the turbulence would only slightly disturb our ride in the balloon. But if an airliner flew by us at 550 MPH, as it encountered the air we experience as smooth, the passengers in the plane might experience what the passengers on the Lufthansa flight did. It is important to recognize that the ride is rough in the plane because the plane is moving rapidly though air that is turbulent because fast-moving air is mixing with slow-moving air.
Imagine the difference if you drove your car across a 3 inch speed bump at 5 MPH versus 50 MPH. Hitting a speed bump in a car at 550 MPH is unthinkable. When your airliner hits a bump at 550 MPH and feels like a car crossing a speed bump, the bump is not 3 inches. It is more like 1/10th of an inch. It is the speed of the plane that causes what passengers feel in turbulence. Passengers in a balloon in the same air would feel little or no turbulence at all.
Do Pilots Know About Turbulence In Advance?
Another person wrote, ""I am flying tomorrow from JFK to LAX and am very nervous, especially about the weather. I saw a story on Wednesday about a Lufthansa flight from Texas to Germany having to make an emergency landing in Virginia because turbulence was so bad - 7 people went to the hospital. Was there any way for the captain of that flight to know the turbulence would be that bad? Should something have been done differently?"
When pilots encounter turbulence, they are required to report it to Air Traffic Control. Since plots monitor radio transmissions to Air Traffic Control, they know where turbulence is being reported. It is only when no planes are in the airspace ahead, or when conditions change, that turbulence is encountered unexpectedly
New technology is helping pilots avoid turbulence. Airlines participating in the IATA (International Air Transport Association) Turbulence Aware program have been fitted their airliners with sensors that measure turbulence. These planes constantly send flight conditions measurements to a ground-based computer. The computer forwards this data to iPads carried by the pilots in the cockpit. This gives them information about the flight conditions ahead in real time.
Is Turbulence Increasing?
Another email said, "Seems like reports of severe turbulence are on the rise. While it may not be an issue for the plane, it’s definitely alarming for us cautious fliers."
Since the jet stream is caused by the earth's rotation, and there is no increase in the earth's speed, there should be no increase in turbulence at cruise altitude. But as temperatures rise, the air at lower altitudes becomes more unstable. Expect more turbulence when taking off or landing, and when climbing or descending.
There is turbulence some place in the world all the time. Actually, lots of places in the world all the time. The question is whether or not your plane will be flying where the turbulence is. Most flights will encounters some turbulence. If turbulence bothers you, book early enough to reserve a seat where the plane moves less. Think of a see-saw. The area of a see-saw that moves least is the fulcrum point. The fulcrum point on an airliner is the wing. A seat over the wing or forward of the wing offers the best ride.
Because unexpected turbulence is not impossible, passengers are told to wear their seat belts - even when the seat belt sign is off - as a precaution. Passengers usually get away with not following these instructions. But now and then, unbelted passengers in the rear of the plane get injured. When they do, the media does their click-bait thing. They tell you passengers had to be taken to the hospital. That is a bit of an exaggeration. Very few injuries require hospital care, but alrlines hope to avoid lawsuits by having passengers with any injuries at all thoroughly examined. The media rarely tells you the injured passengers were were not wearing their seat belt.
