http://ma3naido.blogspot.com/2008/01/importance-of-performance-data.html
IMPORTANCE OF PERFORMANCE DATA
The performance or operational information section of the Airplane
Flight Manual/Pilot's Operating Handbook (AFM/POH) contains the
operating data for the airplane; that is, the data pertaining to
takeoff, climb, range, endurance, descent, and landing. The use of
this data in flying operations is mandatory for safe and efficient
operation. Considerable knowledge and familiarity of the airplane can
be gained through study of this material....view all
http://ma3naido.blogspot.com/2008/01/importance-of-performance-data.html

http://ma3naido.blogspot.com/2008/01/structure-of-atmosphere_08.html
STRUCTURE OF THE ATMOSPHERE
The atmosphere is an envelope of air that surrounds the earth and
rests upon its surface. It is as much a part of the earth as the seas
or the land. However, air differs from land and water inasmuch as it
is a mixture of gases. It has mass, weight, and indefinite
shape....view all
http://ma3naido.blogspot.com/2008/01/structure-of-atmosphere_08.html