ESDU 80032 gives simplified forms of aircraft performance equations and the numerical constants associated with different sets of commonly-used units. These equations complement the more fundamental and detailed treatments given in other parts of the Aircraft Performance Series and are intended for use in project design work with jet or propeller driven aircraft although, in the case of some low-speed aeroplanes, they are adequate for most other purposes as well. The along-flight-path performance equation incorporating a simple parabolic drag law is presented in alternative forms depending on whether speed is expressed in terms of equivalent airspeed or Mach number. Further versions present the variables in the form of non-dimensional groups which are, themselves, of importance in the presentation of measured performance data.