Turbulence (+16 min Audio)

Here’s a way of seeing how bumpy it really is on your plane. Keep a drink on your table during your flight. When it becomes bumpy watch the contents of the glass and see how little gets spilt … even in the worst turbulence. Try that in a car! The bumps in the car are far worse than those of a plane  … but why does it seems so different? Let’s start by explaining very simply how a plane flies and then you’ll know how turbulence can, or can’t affect  what happens to it when it’s flying along with you inside. I’m sure you’d agree with the statement that …  seeing is believing. Just imagine for a moment that we could see the air like a jelly. Thick and visible,   if we could see the plane ‘sitting’ in this jelly even if it weren’t moving we could accept that jelly is thick enough for the plane to almost float on it. It’s hard to imagine that air could be as thick as jelly but the fact is that air does become thicker the faster it’s moving …and you can discover that by putting your head out of a car or train window while it’s moving. If the car or train is moving at very high speed there is so much resistance that it’s impossible to stick your head out. The air certainly becomes thicker than jelly!

When a plane moves through the air, the shape of the wing makes the air ‘thinner’ on the top of the wing and ‘thicker’ underneath the wing. This causes suction on the top and a cushion of air underneath that the plane can sit on. We know this is a fact of science because high-speed boats (hydrofoils) use the same scientific principle. You’ll see that rather than floating on the water it is supported by the ‘wings’ that are submerged. Before the boat gathers speed of course, it floats, like any other sort of boat. The wings of a plane work the same way. The faster it travels through the air the more lift it makes.

But we don’t look at the boat and wonder how it stays up … it seems normal so we don’t even think about it.  Because we can see waves and the tide moving in and out, because we can see ripples and currents in the water, and because we know that boats don’t sink when they go up and down on the waves … we trust them. Floating seems normal whereas flying doesn’t … but they booth use the same principles of physics.

Why is it that we don’t trust planes when they go up and down on the moving currents of air? Seeing is believing … that’s why.

Turbulence may be uncomfortable but that’s not the same as dangerous.

It’s easy for the pilot to fly the plane in turbulence.

The plane is strong enough to withstand the movements.

The plane will not fall out of the sky because of turbulence.

The plane does not move up and down more than a few feet in turbulence. 

Remember that you’re traveling at 600 miles an hour. Try going over a bump in the road at that speed! 

Keep tightening it 

Say to yourself that “turbulence may be uncomfortable, but that’s not the same as dangerous.” 

Do not be alarmed when the pilot puts on the seat belt signs. Nowadays this is more to do with the problems of the airline being sued by passengers and the duty of care it has to the crew. It is not a measure of ‘seriousness’ of the turbulence. In the old days, we’d hardly ever ask the passengers or crew to put their seat belts on. 

It may amuse you to know that we sometimes put on the seat belt signs so that we can keep the passengers in their seats while the cabin crew go about their duties.

When you see the seat belt signs illuminate do not take this as an indication of danger…it is a precaution … however, if you have your belt on you might as well make it useful, so tighten it as much as you can bear it and during the time that you have it on keep pulling it tighter and tighter. Then you’ll move with the plane and not a little while after it. This will make you feel much more comfortable as the plane moves. Even though you will move with the plane your stomach is still free to float around inside you … so you’ll still get some of the feelings of going up and down.

The pilots will be waiting for the report from the cabin crew that the passengers are all secure, and will have reduced speed a little and have made a change to the engine settings … according to the aircraft type. Passengers are always keen to know how long the turbulence is going to last. If I said that a piece of string is anything from about a foot to three feet long then turbulence will last about 15 minutes, maybe an hour at the most. Pilots have the choice of flying around … not a likely choice … or flying at a different height to minimise the effect of turbulence. Pilots will always fly around thunderstorms. 

Say “turbulence may be uncomfortable, but that’s not the same as dangerous.” 

At the riverbank, the water is slowed down which causes ripples and currents. If another river flows in to it then more currents and waves are made. Any change of speed or movement of the water will cause ‘turbulence’. 

If we think of it on an even bigger scale then imagine the effect of two oceans or areas of water meeting each other. In fact around Cape Horn are some of the wildest seas because of large masses of water colliding. It’s the same in the air. 

The movement of the air causes turbulence. It doesn’t have to be a large movement either. I have experienced turbulence when the wind at high altitude has been 4 or 5 Knots. It also depends upon the difference in temperature of the air…

Air rises at the equator because the sun heats the land … this air rises and is replaced by air from the poles. Land masses like America and Europe will also heat the air above them … and that air will be replaced by air above the Atlantic Ocean. These two masses of moving air, one moving northwards colliding with air going to the East or West. That’ll cause turbulence. In reality, though there are several of these cells of circulation each causing disruption to the air and causing turbulence. Air moves around because of these heating effects. Because the movement isn’t smooth, there are bumps, one pilot I know calls turbulence  “ a bit of bumpety bump today folks”