Tackling Turbulence

"Fasten your seatbelts. It's going to be a bumpy night."

That was Bette Davis' sultry warning to party guests in the 1950 film classic All About Eve. The turbulence she was talking about had little to do with rough air. But her advice holds for business jet travelers, especially those who fly in smaller aircraft. At best, turbulence makes for an uncomfortable ride. At worst, it can be dangerous, especially for those not properly secured in their seats.

What is it that makes some flights as smooth as cream cheese while others seem to bounce around the sky like a demon carnival ride? The answer can usually be found on the weather map; but you don't have to be an ace of the isobars to predict when the air is likely to be rough. And if you really don't like the turbulence, there actually is something you can do about it.

Turbulence is simply moving masses of air that meet up with other moving masses of air. They could be traveling vertically in columns or horizontally in waves. It can happen close to the Earth's surface or miles above, where different segments of the atmosphere meet. Taken to the extreme, vertically turbulent air can become a thunderstorm, or even a tornado.

At higher altitudes, turbulence can result when two large air masses meet while moving in opposite directions. Where they converge, the air is sure to be churning. Depending on the relative size and speed of the two air masses, there could be significant disturbance. Pilots check winds aloft before every flight, and when there is a significant divergence in direction or velocity relatively close in altitude, they know that might be an area to avoid, or at least to pass through quickly.

Turbulence from storms is usually easier to predict, but not always. The air can be quite violent for 20 or even 30 miles in front of a line of thunderstorms, depending on how unstable atmospheric conditions are. Humidity, heat and movement of frontal systems each contribute to instability, and since those are all dynamic such turbulence can be difficult to predict exactly. If your crew decides to delay the takeoff until a storm passes, you should respect that decision.

As for en route turbulence, pilots usually share their experience over the radio so air traffic controllers can advise those coming later where the smooth air can be found. Sometimes, there just is no way out. During a trip in my own airplane last summer, I heard airline pilots contacting air traffic control as they approached the sector I was in and requesting clearance to a less bumpy flight level. They each got the same answer; aircraft at all levels were reporting moderate turbulence that would last for the next hundred miles or so. So the seat belt signs stayed on.

Just as choppy seas affect small craft more than ocean liners, passengers on a light business jet will feel the bumps more than those on an airliner. Anticipate this when you fly. If you have control over your travel schedule, you can minimize the possibility of turbulence by flying early in the day. Plan to take off before the sun has had the chance to warm the earth, heating surface air and causing it to rise. That upwardly mobile air becomes speed bumps as high as several thousand feet above the ground. Early morning air is almost always smoother than afternoon air.

And even when you're cruising well above the clouds, keep your belt fastened whenever possible. It is rare, but FAA reports are sprinkled with cases of airplanes that encountered unexpected turbulence at high altitude, injuring a passenger or a flight attendant.

So listen to Bette Davis. She knew what she was talking about.