 Area navigation (RNAV) STAR/FMSP procedures for arrivals serve the same purpose but are used only by aircraft equipped with flight management systems (FMS) or GPS.The purpose of both is to simplify clearance delivery procedures and facilitate transition between en route and instrument approach procedures.A STAR is a flight route defined and published by the air navigation service provider that usually covers the phase of a flight that lies between the last point of the route filed in the flight plan and the first point of the approach to the airport, normally the initial approach fix (IAF).