Standard Instrument Departure Routes and Standard Arrival Routes (SIDs and STARs)
- A Standard Instrument Departure Route (SID) is a standard ATS route identified in an instrument departure procedure by which aircraft should proceed from take-off phase to the en-route phase.
- A Standard Arrival Route (STAR) is a standard ATS route identified in an approach procedure by which aircraft should proceed from the en-route phase to an initial approach fix.
(EUROCONTROL EATM Glossary of Terms)
SIDs and STARs are produced with the object of expediting the safe and efficient flow of air traffic operating to and from the same or different runways at the same or neighbouring airfields.
SIDs and STARs aim to deconflict potentially conflicting traffic by the use of specific routings, levels, speed restrictions and check points. The flight crew shall comply with published SID and STAR speed restrictions unless the restrictions are explicitly cancelled or amended by the controller. Some SID and STAR speed restrictions ensure containment with RNAV departure or arrival procedure, e.g. maximum speed associated with a constant radius arc to a fix (RF) leg (PANS-ATM, Amendment 7 of 2016).
Typically, each runway will have a number of SIDs and STARs to ensure that air traffic is not unnecessarily delayed by deviation from the direct route from or to the aerodrome.
The SID or STAR which a pilot intends to use is usually included in the ATC flight plan.
The dedicated SID/STAR phraseology allows ATC and aircrew to communicate and understand detailed clearance information that would otherwise require long and potentially complex transmissions. Over time, these benefits have been eroded through the development of non-harmonised practices and different meanings being attached to certain elements of the SID/STAR phraseology. Consequently, a mismatch between ATC and aircrew understanding of SID/STAR phraseology presents a safety risk that requires a renewed effort to adopt and apply strictly harmonised SID/STAR phraseology.
In June 2016 ICAO published Amendment 7-A to PANS-ATM, applicable as from 10 November 2016, which includes harmonised phraseologies for issuing standard clearances to arriving and departing aircraft, including clearances to aircraft on a SID or STAR. The phraseology can be consulted in "Further Reading" below. The period over which the changes should be introduced has been notified by ICAO as 12 months commencing 10 November 2016, i.e. implementation date will vary from state to state depending on the NAA. The transition period will likely affect pilots making international IFR flights. Also, controllers from ATC Units in States which have not begun using the new procedures themselves should be aware that pilots from other States which have done so are likely to use them.