The following questions were submitted by C. Harrison of High Point, who recently flew from Greensboro to New York City. Although the flight took place on a clear day, it encountered strong turbulence during the landing.\ Q: Can turbulence cause a crash?
A: Turbulence is rarely serious enough to cause problems for large commercial aircraft. Turbulence severe enough to cause any real problems is usually found only within or very close to thunderstorms.
Q: Are wind shears a part of turbulence? What is the difference between the two?
A: Wind shears and turbulence are very similar. Both are caused by a change in the speed and/or direction of the air through which the plane is flying.
However, turbulence causes only momentary changes in the speed and direction of the air through which the plane is flying. Wind shear causes prolonged changes in the speed and direction of the air.Wind shear is usually only a danger during takeoffs and landings, when air speeds are critically low. At such times, wind shear resulting in a sudden tail wind, for example, could reduce the aircraft's air speed below that at which it can fly.
Again, though, for large commercial aircraft, wind shear strong enough to cause major problems are usually found only around thunderstorms.
Q: All the passengers were frightened. I wish people could be more educated on flying and turbulence. What books are available so that I can read about turbulence?
A: Your local library probably carries, or can get one of the many books on aviation weather. Any book on flight training should also have chapters specifically devoted to weather.
A very comprehensive book on aviation weather is printed by the U.S. government. Called ``Aviation Weather,' it can be purchased in any government bookstore.
Robert Graziani is a commercial airline pilot who lives in Greensboro.
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