A major goal of the Ada language is to decrease the cost impact of software modifications resulting from requirements changes. This paper shows how Ada has the potential to achieve that goal through examples of modifications to the F-16 Trainer Flight Simulator. Ada features not available in Fortran are discussed as they would be applied to the F-16 TFS examples with the potential modification in mind. From the Fortran examples provided, the rationale for many of Ada's features can be seen. The point is made that Fortran is a programming language, while Ada is a design, documentation, and implementation system. Ada addresses all stages of the software development life cycle and is not limited to the coding stage. Many of the tools which Ada provides must be initially applied during design activities if Ada's full benefits are to be realized in reducing the cost impact of software modifications.