Event Extension

Purpose and scope

The purpose of the Event Extension is to enable the digital encoding of the aeronautical data that concerns identifiable operational situations, which result in the temporary or permanent alteration of one or more aeronautical information features or of their properties. Such operational situations can range from a simple runway closure or navaid unavailability to a complex change of the route structure or a military exercise. 

The Event concept is not new in the aeronautical information domain. An “embryo” of the concept is used in the European AIS Database (EAD) in the form of a Private/Public Slot entity. The EAD slots allow grouping together the changes that have a common operational reason and the same effective date. The Eurocontrol Network Manager (NM) CACD system is using a relatively similar “project” concept in order to plan in advance the information about complex situations, such as large military exercises, Olympic Games, etc. when they have a significant impact on the Network operations.

The Event extension provides the following capabilities:

• provision of information about the event itself, such as name, activity, summary, contact details;
• identification of an eventual pre-defined coding scenario, in order to define business rules that concern that scenario and enable the verification of the coding quality. This supports the use of the Event concept in particular for the Digital NOTAM encoding, where very detailed scenarios are identified for situations such as navaid unserviceable, airspace activation, new obstacle, etc.
• identification (by association) of all the data elements that are encoded in relation with the event;
• the possibility to indicate the location of the event in relation with one or more airspace and airports/heliports;
• the possibility to specify common metadata for a group of Timeslices, from different features; for example, they could have the same reason for coming into existence and therefore common metadata;
• indicate which AIS document (NOTAM, AIP, SUP, etc.) includes the same information in a printed/message format. This allows to include digital representation of the AIP AMDT, AIP SUP, AIC or the full content of the NOTAM message;
• allows to establish a hierarchy of Events, by establishing a whole/part association;
• allows to indicate logical dependencies between events, such as an event that is the consequence of another event;
• allows very early information to be encoded about Events that will take place later in the future (the long term planning aspect)

The Event concept was initially developed as part of the Digital NOTAM Event Specification (version 1.0) and validated through SESAR trials and initial Digital NOTAM deployments, such as in particular in the United States Federal NOTAM System (FNS). An extension of the initial Event concept was developed in support for the long-term planning needs of the Civil-Military Airspace Management (eASM) process. The experience gathered with these earlier implementations and developments were taken into consideration into this specification.

The Event Extension is focused on the aeronautical information domain and it is built on the foundation of the Aeronautical Information Exchange Model (AIXM). It shall be kept in mind that one of the design objectives for AIXM (after version 5.0) is to model the full lifetime of aeronautical information features, including creation, permanent and temporary changes, decommissioning, etc. without recourse to any specific message. This enables the use of AIXM encoded data in combination with generic data exchange standards, such as Web Feature Services (WFS). An Event is also an AIXM feature, therefore it can also have a full lifecycle as any other aeronautical feature: it can be created, changed, cancelled, etc.
The Event Concept is targeted primarily for application in systems that support the encoding and processing of Digital NOTAM and automatic generation of AIP/charts content. 

UML Model

The Event class

The UML model that defines the Event class and its main properties is shown in the following diagram.

XML Schema

Usage and applications