ESDU 86004 gives equations and curves for a method that neglects the effects of any consequential changes in the independent variables although, at the cost of increased complexity, a means of including such effects (in particular compressibility effects on drag) is provided. Several worked examples show how well the simple method compares with actual operations data. This document is an Addendum to ESDU 80032, and illustrates how the equations of motion given there combined with a parabolic drag law yield valuable results.