CHANGES TO SIDS & STAR PHRASEOLOGIES

 

​​​​​​​​​​​​​​​​​​​Background

 

Standard Instrument Departures (SIDs) and Standard Instrument Arrivals (STARs)​ provide a safe and efficient way of prescribing a large amount of information through procedure design. Both depict the lateral profile of an instrument departure or arrival route and the associated level and speed restrictions.

 

The use of SID/STAR phraseology brings significant benefits. It enables efficent and concise communication. It allows ATC to issue, and aircrew to understand detailed clearance information that would otherwise require long and  complex transmissions.​


Over time though, these benefits have been eroded. The development of non-harmonised practices induced that different meanings would become attached to certain elements of SID/STAR phraseology.  Confusion crept in. Pilots became uncertain of what  air traffic controllers meant.  Extra questions and  request for clarification appeared on frequencies that were already cluttered. 


 

This increased safety risk called for a  renewed effort, to strenghten and harmonize the SID/STAR phraseology.

 

So what is new ?

The change:

  • provides core phraseology that positively reinforces that the lateral, vertical and speed requirements embedded in a SID or STAR  continue to apply, unless explicitly cancelled or amended by the controller;
  • provides additional phraseology that enables to lift any level or speed restrictions,  as local circumstances, practice or procedures permit;
  • harmonises the  phraseology to bypass waypoints or amend the lateral profile of SID or STAR.

 

 And what doesn't change?

 

  • The requirement in ICAO Annex 10 for the highest standard of discipline to be applied to all communications at all times​​ does not chang​e.
  • Speed limits associated to airspace classification (ICAO Annex 11 Chapter 2 and Appendix 4) are not cancelled by the instructions in the SID and STAR procedures.
  • The requirement for a QNH altimeter setting to be included in the descent clearance when first cleared to an altitude​ below the transition level, except when it is known that the aircraft has already received the information (PANS-ATM 4.10.4.5 refers), does not change.
  • ​And finally, while pilots and ATS providers are expected to comply with the revised phraseology, in unusual or unforeseen circumstances it may not be possible to apply the phraseology as intended. Should this happen, pilots and ATS personnel are still expected to use plain language, which must be as clear and concise as possible.​​​
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