In aviation, a standard terminal arrival route or standard terminal arrival (STAR) is a published procedure followed by aircraft on an IFR flight plan just before reaching a destination airport.
A STAR usually covers the phase of a flight that lies between the top of descent from cruise or en-route flight and the final approach to a runway for landing.
A typical STAR consists of a set of starting points, called transitions, and a description of routes (typically via VOR's and intersections) from each of these transitions to a point near a destination airport, upon reaching which the aircraft can join an instrument approach (IAP) or be vectored for a final approach by terminal air traffic control. Not all airports have published STARs; however, most relatively large or not easily accessible (for example, in a mountainous area) airports do. Sometimes several airports in the same area share a single STAR; in such case, aircraft destined for any of the airports in such group follow the same arrival route up until reaching the final waypoint, after which they join approaches for their respective destination airports.
Naming conventions for STARs vary by country and region. In Europe, they are often named after the transition waypoint, followed by a digit that is incremented with each revision of the procedure, and a letter designating the runway for which the STAR is intended. In the United States, STARs are named after waypoints, or unique features of the STAR, or geographical features, followed by a digit indicating the STAR revision. A single STAR in the U.S. may serve for multiple runways and transitions; European STARs are more likely to be independently published for each runway and/or transition.
Not all STARs are for IFR flights. Occasionally STARs are published for visual approaches, in which case they specify visible landmarks on the ground and other visual reference points instead of waypoints or radio navigation aids.
STARs can be very detailed (as is often the case in Europe), allowing pilots to go from descent to approach entirely on their own once ATC has cleared them for the arrival, or they can be more general (as is often the case in the United States), providing guidance to the pilot which is then supplemented by instructions from ATC.