This report contains the outcome of a study performed by Swedavia, Eurocontrol and Lufthansa Aviation Training, where GNSS based curved Instrument Approach Operation has been performed in the TMA. This study has been achieved by using various Flight Simulator Training Devices, normally used by airlines for Flight Crew training and checking. The study has taken advantage of the latest ICAO Navigation Specification A-RNP, and also relaxed current ICAO design criteria, taking advantage of state-of-the-art Navigation Specification characteristics to investigate potential benefits and operational acceptance that enhanced curved Instrument Approach Procedures could offer for the broader aviation community, for example the potential to shorten Initial and Intermediate approach segments of an Instrument Approach Procedures thanks to the increased navigation performance and advanced navigation functions, thus enabling flight path shortening, resulting in lowered environmental impact. The results from the study prove the high potential of using A-RNP characteristics for the Initial and Intermediate approach segments to enable flight path shortening in the vicinity of the destination airport, by relaxing current ICAO design criteria, through reducing the Final approach segment down to 3 NMd and removing any additional aligned stabilization segment on the extended Runway centerline. Furthermore, by using modern navigation capabilities to intercept the Final approach segment, available airspace in the TMA can be used more efficiently. Overall, these novel Instrument Approach Procedures used in this study can reduce the distance flown with at least 4 NM by shortening the downwind segment by 2 NM and by removing a 2 NM stabilization segment prior to the Final approach segment. This would enable more efficient, fuel- and noise-optimized routings for future operations.