The effect of aircraft noise, fuel use and atmospheric emission can impact the quality of life of populated areas near to airports. This environmental issue results in restrictions for air traffic procedures, aircraft manufacturing and airport structures. Curved and Continuous Descent Approach can be adopted in order to reduce environmental impact during approach and landing phases. This paper provides a study of Curved and Continuous Descent Approach concept for the future efficient flight operations in TMA. The intent is to provide the main inputs necessary to implement a system able to generate optimized descent profiles for the Efficient Air Transport System through tools and algorithms, which minimize the environmental impact. In particular, this study investigates on differences between conventional descent and proposed curved and continuous descent technique, starting from an analysis of procedures for a generic descent trajectory. Furthermore, mathematical modelling of descent profiles, high-level requirements and performance assessment are discussed here in order to provide the basis for implementing the model, route structures and system operations taking into account the current rules of the air and the future ATC technologies.