VOR

Introduction & Background

This topic contains only those PANS-AIM requirements relevant for a VOR. For general PANS-AIM requirements valid for all kind of Radio navigation aids see topic Basic Data for Navaid.

A VOR (VHF omnidirectional radio range beacon) is a short-range, very-high-frequency omnidirectional beacon, which provides an indication in the aircraft of the bearing of the beacon, or left-right track indication.

For a VOR, PANS-AIM requires some specific properties as part of the minimum AIP data set. These are

...identification, name, aerodrome served, hours of operation, ..., frequency..., position, ..., zero bearing direction

In addition, PANS-AIM ENR 4.1. and also AD 2.19 / AD 3.18 require

...for VOR, station declination to the nearest degree used for technical line-up of the aid, ...

...If the operating authority of the facility is other than the designated governmental agency, the name of the operating authority shall be indicated in the remarks column. Facility coverage shall be indicated in the remarks column.

The diagram below shows the AIXM classes, including the relevant data types, needed to encode that information The main class is the VOR, which is a specialisation of the NavaidEquipment.

VOR Designator & Name

In general, a VOR will carry a three letter character identifier. The VOR.designator attribute is used to code that data.

The long name given to the VOR is coded using the VOR.name attribute.

VOR Type

It is not required by PANS-AIM to provide the type of a VOR. Because in some State AIPs this information is published, it is also covered by this guidelines.

The VOR.type attribute may be used to code that information. The list of values of the CodeVORType class contains:

Aerodrome Served

See topic Basic Data for Navaid.

Hours of Operation

See topic Hours of Operation for Navaid.

Frequency

The VOR.frequency attribute is used to code the value of the frequency. This can be any decimal value greater than 0. However, there is a coding rule that define a range of acceptable values.

The corresponding data type ValFrequencyType contains a uom attribute. For a VOR, only the value equal-to 'MHZ' shall be used.

According to ICAO Annex 10, Volume 1

The VOR shall operate in the band 111.975 MHz to 117.975 MHz. ...The channel separation shall be in increments of 50 kHz referred to the highest assignable frequency.

Position

See topic Navaid Position & Elevation.

Station Declination & Zero Bearing Direction

The VOR.zeroBearingDirection is used to code the direction of the 'zero bearing' provided by the station. For example: magnetic north ('MAG'), true north ('TRUE').

The angular difference between the direction of the 'zero bearing' indicated by the station and the direction of the True North at the time the VOR station is calibrated is coded by the attribute VOR.declination.

In case the VOR is assigned to an AirportHeliport (see topic Basic Data for Navaid), the magnetic variation of the VOR has to coincide with that of the related airport/heliport.

In some AIPs, also the date (year) when the station declination was measured is published. Unlike for magnetic variation there is no dedicated attribute for station declination contained in AIXM 5. Corresponding information can only be recorded using a Note.

According to PANS-AIM, for VOR the specific station declination should be provided rather than the local magnetic variation. However, in many AIPs the magnetic variation is published instead.

Operating Authority

See topic Operating Authority for Navaid.

Facility Coverage

See topic Facility coverage.

For more details see topic

Navaid Collocation

A VOR instance may be collocated with a DME.

A VOR (and DME) may only maintain a single collocation relationship at a time, which means that it is not possible to collocate a VOR with two different DMEs. In the AIP collocated VOR and DME Navaids are usually referred to as VOR/DME or DVOR/DME respectively.

A VOR instance may also be collocated with a TACAN.

A VOR (and TACAN) may only maintain a single collocation relationship at a time. In the AIP collocated VOR and TACAN Navaids are usually referred to as VORTAC or DVORTAC, respectively. 

For more details see topic Landing Systems & Navaid Collocation.

Coding Examples

Coding examples can also be found in the AIP Data Set - Specimen (DONLON):

References