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SIDs and STARs: how instrument procedures work

The published arrival and departure routes that connect the runway to the airways — and how they shape your radar picture.

Airports don't just launch aircraft in any direction. Departures and arrivals follow published, coded routes that keep traffic predictable, separated from terrain and noise-sensitive areas, and neatly connected to the en-route airway network. These routes are SIDs and STARs.

SIDs — Standard Instrument Departures

A SID is a published departure route from a specific runway out to a fix on the airway system. It tells the crew exactly how to fly the first part of the climb: which way to turn after take-off, which waypoints to cross and often what altitude or speed restrictions to respect. SIDs keep a stream of departures on a known track, so as the controller you can climb them predictably and hand them to the next sector once they are clear of the arrivals.

STARs — Standard Terminal Arrival Routes

A STAR is the mirror image: a published route from a fix on the boundary of the terminal area inward toward the approach. Arrivals join the STAR from the airways and follow it down, descending as they go, until they reach the point where the approach controller takes over with radar vectors for the final sequence. STARs funnel traffic from many directions into a small number of tidy arrival flows.

Fixes, transitions and the boundary

Both SIDs and STARs are built from fixes — named five-letter waypoints such as LORNI or BEGLA — joined by tracks. The first fix of a STAR is usually an entry point on the terminal-area boundary; the last fix of a SID is usually an exit point onto an airway. In the ATC Radar Simulator every airport lists its real SIDs and STARs, and the flight strip shows each aircraft's assigned procedure so you always know where it is going.

Why they matter to the controller

Procedures do a lot of the organising for you. Because arrivals are already funnelled onto a STAR and departures onto a SID, your job becomes fine-tuning — vectoring arrivals off the STAR to build the final sequence, and climbing departures on their SID and handing them off. When traffic is light you might clear an aircraft to fly the whole procedure; when it is busy you take over with radar headings to squeeze in the spacing. Understanding the SID and STAR structure of an airport is the first step to controlling it well.

See the procedures for each airport on its airport page, then take control in the simulator. For the bigger picture, read how approach radar control works and the ATC glossary.