Summary: My Freeware Atmos is a small utility allowing you to calculate the relationships between geometric altitude, and pressure, density and temperature of the (1976) Standard Atmosphere. 
Singular output is possible as function of altitude, relative density or relative pressure (to sealevel) 

or in a tabular format as function of the start altitude level, the number of steps and stepsize: 

Each parameter may be defined in SI or English units and can be stored.

For both the Series 3 and Series 5 is a different version: respectively: ATMOS3 and ATMOS5 

History : 

• Version 2.2 (23-12-02] Conversions between equivalent and true airspeed added + small bug fixes. 
  
• Version 2.1 (22-07-02] Now also suitable for the Revo (Plus) and Mako! 
  
• Version 2.0 (08-11-99] Ported for the Series 5 
  
• Version 1.1 (22-02-99) Better event handling and extended help function. 
  
• Version 1.0 (02-01-99) Original version.