Since 2007, there have been 58 reported incidents of turbulence on U.S. airlines, according to the Federal Aviation Administration (FAA), which resulted in 64 serious injuries and 97 minor injuries.
Having recently experienced a Derecho on the east coast of the United States there is no doubt that we need to pay more attention to weather events that appear to be more severe and frequent, especially in the summer months. The CNN article provides some valuable passenger-oriented information. To add to the CNN article the following summary is provided.
The impact that turbulence has on an airplane varies with the difference in wind speed in adjacent currents, the size of aircraft, wing loading, airspeed, and the altitude of the airplane. When an airplane moves rapidly from one current to another, it undergoes abrupt changes in acceleration. Commercial airplanes are designed and built to withstand severe turbulence and encountering turbulence extreme enough to damage a commercial airplane is extremely rare.
Here are some of the different kinds of turbulence that airplanes can encounter:
Clear-air turbulence, known in the industry as CAT, is common at high altitudes but hard to predict since it’s invisible to weather radar, which can only see inside of clouds. It’s usually caused by shifting jet streams.
Wind shears in the upper atmosphere are usually vertical but tend to be horizontal closer to the runway. Horizontal wind shears can create eddies or swirls, of air that causes turbulence. A microburst is a type of wind shear associated with a thunderstorm and caused by a current of sinking air. A microburst often occurs as an airplane is departing or landing.
Wind blowing across a mountain pass can take on the form of a wave as it comes in contact with the mountain, forcing air over it and setting it in oscillation. These atmospheric waves may become turbulent, like a breaking ocean wave. The waves can extend 100 miles or more downwind from the mountain and well above even the highest peaks, sometimes into the lower stratosphere. Turbulence in a mountain wave can range from very mild to violent.
Airplanes can also cause turbulence. Just like a ski boat creates eddies and waves in the water, rapidly spinning air currents can develop off the wing tips of an aircraft. These vortices can cause a following plane to roll. Such air currents decay fairly rapidly, so if planes are far enough apart, it’s not a problem.
Convective currents, most active on warm summer afternoons, are a common cause of turbulence at low altitudes and can impact airplanes during take-off or landing. Air that is heated near the ground rises, but since different surfaces have a hotter surface area than others the air heats unevenly, causing different hot spots and abrupt changes in airspeed that can be dangerous at low altitudes.
Thunderstorms can also create severe turbulence that pilots are taught to avoid. Air currents can be going up in some places and coming down suddenly vertical, shearing-type currents and can be dangerous.
The next time you are on a flight wear your seat belt at all times – it just makes total sense and it will save you from being injured when your flight encounters unexpected turbulence.Share this article: