Moveable surfaces on an airplane's wings and tail allow a
pilot to maneuver an airplane and control its attitude, or
orientation. These control surfaces work on the same principle
as lift on a wing. They create a difference in air pressure to
produce a force on the airplane in a desired direction.
The main purpose of the tail is to provide stability. If
tilted by a gust of wind, a stable airplane tends to recover,
just as a ball lying at the bottom of a bowl will roll back to
the center after being disturbed.
(Rev. 09/18/96)