There are several open questions/issues about the encoding of this information, regarding both PANS-AIM and AIXM 5. Thus, this page is not to be seen as coding guidelines but rather as discussion of the issues detected.

For the AIP data set PANS-AIM requires 2 properties related to Performance Based Navigation (PBN) of a route segment.

Designation of the navigation specification(s) applicable to a specified segment(s) -  There are two kinds of navigation specifications:

Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH.

Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1.

Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace requirements
This property is split into 2 sub-properties

The navigation accuracy requirement for each PBN (RNAV or RNP) route segment

Indication on the sensor requirements including any navigation specification limitations

It is not clear what is the difference between the properties Navigation specification and Navigation performance requirements, Both seem to be used for providing the same information, e.g, RNAV 10, RNP 4, etc.

ICAO Doc 9613 (PBN Manual) describes the following designation of Navigation Specifications:

Th following table shows the Application of navigation specification by flight phase:

AIXM 5.1.1 provides two attributes regarding navigation specifications for a RouteSegment. Both seem to be insufficient to code the designation of the PBN specification.

  • navigationType is basically used to encode if the route is 'CONV 'or 'RNAV', but is not intended to code the PBN specification. Although, 'OTHER' could be used to define PBN Navigation Specifications, e.g. 'RNAV 5' or 'RNP 4'.
  • requiredNavigationPerformance is intended to code RNP values. RNAV values are not considered.

Another option would be to code a FlightRestriction for a RoutePortion. A related FlightConditionElement may be encoded with a corresponding AircraftCharacteristic.navigationSpecification. The code list for this attribute CodeNaviagationSpecificationType contains all required values.

However, it is not clear if the actual intention of the FlightRestriction model of AIXM is to encode that kind of information.

The AIXM definition for FlightRestriction is:

A rule meant to regulate the use of the route network, by identifying a set of flights which fulfil a combination of elementary flow conditions and either forbidding them on a particular routing or obliging them to follow one routing out of a set of mandatory alternatives.