Aviation Weather

full text of the classic FAA guide

Chapter 6
STABLE AND UNSTABLE AIR

To a pilot, the stability of his aircraft is a vital concern. A stable aircraft, when disturbed from straight and level flight, returns by itself to a steady balanced flight. An unstable aircraft, when disturbed, continues to move away from a normal flight attitude.

So it is with the atmosphere. A stable atmosphere resists any upward or downward displacement. An unstable atmosphere allows an upward or downward disturbance to grow into a vertical or convective current.

This chapter first examines fundamental changes in upward and downward moving air and then relates stable and unstable air to clouds, weather, and flying.

Table of Contents
Previous Section: In Closing
Next Section: Changes Within Upward and Downward Moving Air

 

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