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Only the VOR has also a zeroBearingDirection, a code indicating the direction of the 'zero bearing' provided by the station. For example: magnetic north, true north.
The Navaid class is also used to code landing systems (e.g. ILS, Localizer only, MLS). It will be comopsed of the corresponding instances of NavaidEquipment, e.g. Localizer, Glidepath, MarkerBeacon, DME, etc.). Finally, the Navaid and not its individual components aisInstalledAt a RunwayDirection.
A NavaidEquipment isUnderResponsibilityOf an OrganisationAuthority.
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