An arrival segment permits transition from the en-route phase to the approach phase. The arrival segment starts at the latest en-route point and ends at the initial approach fix (IAF).
The arrival segment can be a:
Omnidirectional or sector arrivals can be provided taking into account minimum sector altitudes (MSA).
A standard instrument arrival (STAR) is a designated instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, with a point from which a published instrument approach procedure can be commenced.
Standard arrival clearances for arriving aircraft shall contain the following items:
The clearance to follow the appropriate STAR will normally be issued by ACC without prior coordination with the approach unit.
When an arriving aircraft on a STAR is cleared to descend to a level lower than the level(s) specified in the STAR, the aircraft shall follow the published vertical profile of a STAR, unless such restrictions are explicitly cancelled by ATC. Published minimums levels based on terrain clearance shall always be applied.
An omnidirectional instrument arrival is an instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, direct to a point generally the initial approach fix - IAF - from which a published instrument approach procedure can be commenced.
Omnidirectional or sector arrivals can be provided taking into account the minimum sector altitude (MSA). Pilot shall maintain his aircraft above MSA until reaching the initial approach fix.
Minimum sector altitude (MSA) or terminal arrival altitude (TAA) are established for each aerodrome and provide at least 300m (1000ft) obstacle clearance within 46 km (25 NM) of the navigation aid, initial approach fix or intermediate fix associated with the approach procedure for that aerodrome.
Some arrival procedures are published without any defined track after a specific fix. In these procedures, you may find 'vector' or 'radar' words in the diagram or in the description text. These approach procedures are mainly linked with air traffic controllers who give radar vectors during the approach in busiest areas.
When terminal area radar is employed, the aircraft is vectored to a fix, or onto the final approach track, at a point where the approach may be continued by the pilot by referring to the instrument approach chart.