Turbulence

Turbulence - How Much Does The Plane Move?

In turbulence, it feels like the plane is moving a great distance up and down. Anxious passengers often ask if it is ten or twenty feet, or hundreds of feet. It is neither; it is less than an inch. It is very hard to understand this, but if you have played croquet, you may remember a strategy called "sending your opponent". It is also called "taking a croquet stroke", or "sparking". An understanding of what happens can help you understand how less than an inch of movement by the plane can feel like far more.

During a game of croquet, if you are able to hit an opponent's ball with your ball, you are then entitled to "send your opponent". You do this by placing your ball in contact with the opponent's ball. Then, you place the sole of your shoe on top of your ball, maintaining a strong pressure on your ball, so that when you strike your ball hard with your mallet, your ball moves only a fraction of an inch, but your opponent's ball is sent several feet away.

Something similar happens in turbulence. The plane, like your ball, moves only a fraction of an inch during turbulence. Just as your ball is restricted by your foot, the plane's movement is restricted by the jello-like thickness of the air.

You as a passenger are like the opponent's ball. You are caused to move several inches even though the plane -- like your ball held underfoot -- moves only a fraction of an inch.

Because of speed, the air outside the plane is as thick to the plane as jello. But inside the plane, the air is like air you normally breath. The thick air outside restricts the plane's movement like your foot restricts your ball's movement. The plane is jolted by turbulence just as your ball is jolted when hit by your mallet. But the jolt amounts to nothing; neither your ball or the plane moves more than a fraction of an inch. Yet, the jolt causes you as a passenger, like the opponent's ball, to move a greater distance.

When watching a croquet game, if you were to observe only the opponents ball, you would see it moves ten or twenty feet. You might get the idea that whatever caused the ball to move ten or twenty feet must have moved at least that much, and might have moved more. But you would be wrong. The plane, like your ball, moves only a fraction of an inch. But that fraction of an inch transmits enough intensity to cause you - like the opponent's ball - to to be moved more.

Knowing It Has No Bearing On Safety, Turbulence Means Nothing At All To Pilots

To help you understand that turbulence is not in any way a safety concern, consider this. A pilot flying cargo, such as UPS or FEDEX, would not even bother to press the mike button and ask for a smoother altitude. To a pilot, turbulence simply does not matter. Pilots are so used to it that turbulence that would cause an anxious flier to be very upset would not even be noticed.

Years ago when we did live courses and took people in the course on a "graduation flight", many times I was asked "Is this turbulence dangerous"? My automatic response was, "Turbulence? WHAT Turbulence?" Not only had I not noticed it, I couldn't even notice it after being asked about it. It just did not register on my Richter Scale.

"But Turbulence Is Frightening Because It Is Out Of Control"

Think about the temperature of the air outside. Some days it reaches almost 100 degrees, and some days it is below freezing. But, though the temperature - like turbulence - is not controlled by you or me, it always falls with a certain range. In the U.S., it rarely goes below minus 25 or above plus 125.

Because we know the temperature falls within a certain range, and that range is limited, we have learned how to deal with all the temperatures we may encounter. The same is true of turbulence. It is never above a certain level. But I suspect an anxious flier doesn't really understand this, and things it might become so great it could threaten the plane.

No way! We know the most intense turbulence can become and we build airliners with twice as much strength as is needed for the most intense turbulence possible.

So you understand WHY turbulence is limited, consider this. Turbulence - the kind you get at cruise altitude - is called Clear Air Turbulence, or CAT. It is caused when the jetstream, which is a stream of fast-moving air, scrubs alongside air that is not moving. The speed of the jetstream is limited. How? Consider what causes the jetstream: the earth's rotation. Since the earth's rotation is constant, the maximum speed of the jetstream is restricted to what that constant speed of rotation can produce. And, since turbulence is caused by the interaction of fast-moving air and air that is not moving fast, the amount of turbulence has to fall within a certain range, a range that is not controlled by humans, but is in fact controlled by the earth.

That certainly should help you understand that turbulence is, in a way, very much controlled, and thus is not a threat.