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The point at which an aircraft navigating on an ATS route segment defined by reference to very high frequency omni directional radio ranges is expected to transfer its primary navigational reference from the facility behind the aircraft to the next facility ahead of the aircraft.
AIXM 5.1(.1) defines the ChangeOverPoint class as follows:
The distance from the start of the route portion to the position where change over occurs for VOR defined routes
In AIXM 5.1.1, the ChangeOverPoint is related to a RoutePortion and not a route segment. Hence, to encode COP information, also a corresponding RoutePortion has to be encoded. The ChangeOverPoint.applicableRoutePortion is used for that purpose.
The ChangeOverPoint.distance attribute is used to define the distance from the RoutePortion.start to position of the change over point. Only the distance from the start of the route portion is encoded.
The distance from the end of the route portion can be derived from the length defined by the start and end of the RoutePortion or be encoded as a Note for the ChangeOverPoint.
The ChangeOverPoint.location may be used to define the position of COP as SignificantPoint. In this regard, only Point shall be used as SignificantPoint.
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In the AIP information about the COP may be published in section ENR 3 or on en-route charts.
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Coding Rules for Change Over Point
| Identifier | Data Encoding Rule | Justification | Data Verification Rule (UID) | Remarks |
|---|---|---|---|---|
| RSG-501 | The SignificantPoint used as start of the RoutePortion as ChangeOverPoint shall be either a Navaid.type equal-to 'VOR_DME' or a 'TACAN' or 'VORTAC'. | Data consistency | TBD | |
| RSG-502 | The SignificantPoint used as end of the RoutePortion as ChangeOverPoint shall be either a VOR or a TACANeither a Navaid.type equal-to 'VOR_DME' or 'TACAN' or 'VORTAC'. | Data consistency | TBD | |
| RSG-503 | The If a SignificantPoint is used for the ChangeOverPoint.location it shall be a Point. | Data consistency | TBD | |
| RSG-504 | The ChangeOverPoint.distance shall be the distance from the start of the related RoutePortion. | Data consistency | TBD |
Coding Examples
The figure below gives a simple example of a change over point:
More Examples TBD in the scope of the AIXM Coding Examples can be found in the DONLON AIP data set sample file.
| No. | Description | XPath Expression |
|---|---|---|
| COP-EX-01 | Change over point | //aixm:ChangeOverPointTimeSlice[@gml:id ='COP_WOB_EKO'] | |