SIDs and STARs have proven to be effective means of ensuring that the flow of traffic to/from an airport is as efficient as possible and that potential conflicts are procedurally and safely managed. This is particularly so when combined with optimum airspace design in a PBN environment. Additionally, they provide a means of prescribing and representing the large amount of information associated with the lateral and vertical profiles an aircraft is required to fly.
However, over time, some of the benefits of SIDS and STARS have been eroded as diverging and sometimes conflicting meanings were attached to elements of the phraseology. In particular, there were reports of significant variances in the application of level and speed restrictions, leading to misunderstandings between flight crews and controllers, a number of incidents and a very real safety risk.
To mitigate this risk and at the request of the aviation community, work was undertaken by the ICAO ATM Operations Panel (ATMOPSP), with extensive consultation throughout the development process. The agreed outcome led to new SID/STAR phraseologies that became applicable in 2016.
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