Procedure (overview)

The abstract Procedure class defines the properties (attributes and associations) that are common to SID, STAR and IAP. It is then specialised into StandardInstrumentDeparture (SID), StandardInstrumentArrival (STAR) and InstrumentApproachProcedure (IAP), as visible on the following diagram:

The most important common Procedure associations and attributes are listed below:

• services (airportHeliport) association indicating the AirportHeliport associated with the procedure. For each of its three specialisation (SID, STAR, IAP), it is possible to associate directly the take-off/landing area(s) served, such as runway/FATO or TLOF. That association is not visible on this diagram, it will be discussed later in this document;

• isProtectedBy association linking the procedure with the relevant SafeAltitudeArea, (for example, Minimum Sector Altitudes);

• isBasedOn association allowing to identify the main ground navaids, the special navigation system (such as GNSS) or eventually the radar service that is used during the procedure. For example, for an ILS approach, the corresponding Navaid would be associated. For each procedure leg it is possible to indicate more precisely the navaid or other guidance service that is used, either as along track or for forming fixes. That association is not visible on this diagram and it will be discussed later in this document;
  
  

  AIXM 5.1(.1) Model issue

  There is a discrepancy between the multiplicity of this association in the UML model (0…*) and the XML Schema (0...1). In the current AIXM version (5.1.1), only one GuidanceService can actually be associated with the Procedure. This has been recorded as issue AIXM-178 in the AIXM CCB.

• isLimitedTo association with the AircraftCharacteristics object allowing to indicate that a procedure is designed only for aircraft with some specific characteristics, such as fixed wing or helicopter, landing category (‘A’, ‘B’, etc.), specific navigation capabilities (such as “RNP approach capability”), etc.
• isActiveBy association with the ProcedureAvailability class enabling the coding of temporary situations, when a procedure is not available.
• name attribute intended mainly for IAP, as they do not have a coded identifier. For SID and STAR, the designator attribute (defined in the respective derived classes) shall be used in order to store the coded identifier (for example as ‘KODAP2A’, according to the ICAO Annex 11 rules).
• instruction attribute supporting the provision of a textual description of the procedure, as free text or applying a formalised description concept (such as “[A800+; M047; R]->ARDAG[A3000]-...”)
  the RNAV attribute is a simple ‘YES’/’NO’ value, indicating that the procedure is only for RNAV equipped aircraft.