The AIXM data model, in particular for the airport and navaid related data, enables the coding of usage/availability/status both for individual aeronautical information features (such as an aircraft parking stand, etc.) and for "global" features (such as an apron, a runway or the airport/heliport itself). Thus, if a 'child' feature (such as an aircraft stand) is unavailable, it is also possible to code a 'limited availability' situation for the 'owner' feature. This would unnecessarily increase the complexity of the coding scenarios and could give unnecessary "limited availability' warnings to some data users, for which maybe the unavailability of the lower-level elements is irrelevant. Therefore, the principle applied in the coding scenarios is that the usage/availability/status is coded only on the aeronautical information feature affected, without duplicating the information at the level of the parent feature. It is left for the data users to derive the necessary information, according to their operational needs, with regard to the usage/availability/status of the parent aeronautical information features.
Event operational location
An Event may be associated with one or more airports or with Flight Information Regions (FIR), in the same way that a NOTAM location is declared in item A. The main purpose of this association is to support the selection of events that need to be presented in the airport or route sections of Preflight Information Bulletins (PIB). This association expresses an "operational location", which may be different or more complex than the simple geographical location of the aeronautical feature change of the Event. For example, a temporary restricted area might have an operational significance for an airport that is not directly in its vicinity. The Event may in this case be explicitly associated with the airport concerned, in order to ensure that the information about the airspace restriction is communicated in the PIB for that airport.
There exist many operational dependencies between situations that can affect various aeronautical features. For example: