Related procedures in PANS-ATM became applicable on 10 November 2016 resolving longstanding issues related to the clarity of SID/STAR procedures. These procedures are based on a number of essential considerations, such as the need for ATCOs to communicate their intention to the flight crews clearly and succinctly, and for flight crews to fully understand the ATCOs' intent.
In particular, the revised procedures provide improved clarity of clearances for speed and level restrictions on SIDs and STARs, including the waiving of published restrictions. The procedures consist of explicit instructions, with no implied clearances.
In designing these procedures, one of the main requirements was that the procedures be suitable for global implementation, which is important in maintaining a safe aviation environment.
SID/STAR procedures are a means of graphically communicating large amounts of complex information that would otherwise need to be issued by ATCOs.
SIDs and STARs are also used to de-conflict the departure and arrival paths of flights, and leverage the capabilities of modern flight management systems to fly precise trajectories. All of these, when coupled with good airspace design, facilitates the use of continuous climb operations (CCO)/continuous descend operations (CDO) procedures leading to an overall reduction in phraseology, workload and improves operational efficiency.
As an example of the benefits that can be realized, one Member State achieved 70%+ reduction in incidents of SID/STAR non-compliance during the first month of implementing the 2016 ICAO procedures. Additionally, the State foresees an annual fuel savings of $10M (USD) and a 100,000 metric ton reduction in CO² emissions though increased use of CCO/CDO procedures.
It is clear that the widespread use of SIDs and STARs, combined with efficient airspace design and modern aircraft capabilities, are key enablers in optimizing the use of the airspace around an airport.