VOR Concepts/Navigation

One of the most confusing things to new pilots when learning navigation techniques is VOR navigation.

A VOR or Very High Frequency Omni directional Range transmitter is a device that transmits 360 radials or 'lines' outward from the transmitter itself. These radials coincide with the magnetic compass to identify where an aircraft is in relation to the VOR transmitter or station.


Types of VOR Stations

As shown on a sectional chart, a VOR station is identified by a number of different symbols which represent each stations capabilities. The type of VOR stations include:

  • - VOR: Basic VOR capabilities (radials, bearing to)

  • - VOR/DME: Basic VOR with Distance Measuring capabilities

  • - VORTAC: VOR/DME with Military capabilities


 

VOR stations on Sectional Charts

As can be seen on this chart excerpt, the VOR station at Manteca (ECA - Bottom left of this chart) radiates its navigation signals on frequency 116.0. The Linden VOR station (LIN - upper right of this chart) radiates its navigation signals on frequency 144.8.  Each line on the station's compass rose indicates a radial which can be used to estimate an aircrafts position in relation to the station.

Example:  If I say I am on the 030 radial of the Manteca (ECA) VOR, then I am North-East of the VOR station.  I can also say that if I am traveling on the 270 radial of the Linden VOR, then I am west of the VOR station.

Each radial represents the magnetic position an aircraft may be in relation to the station.  This gives the pilot an easy to use reference to the station.

 

 

VOR Orientation

What is the methods used for orienting yourself on a VOR?  It's actually very easy with just a couple of terms that need to be defined:

  • Radial:  A magnetic line that extends from the VOR that an aircraft can identify on their VOR indicator with a centered needle and a 'From' indicator

  • Bearing To:  A course flown to to the VOR station that an aircraft can identify on their VOR indicator with a centered needle and a 'To' indicator

Example 1:  On a Radial

As shown on the left, the aircraft is located on the 030 radial flying away 'From' the VOR station.  As can be seen to the right, the heading indicator (lower left, Blue tint) shows a magnetic heading of 030 while the VOR indicator (top right, red tint) shows a centered needle with 030 at the top of the indicator and a from indication (down arrow) at the bottom of the indicator.

Example 2:  On yet another Radial

As shown on the right, the aircraft is located on the 270 radial flying away 'From' the VOR station.  As can be seen on the left, the heading indicator (lower left, Blue tint) shows a magnetic heading of 270 while the VOR indicator (top right, red tint) shows a centered needle with 270 at the top of the indicator and a from indication (down arrow) at the bottom of the indicator.

 

 

 

 

Example 3:  To the left of a selected radial

This next VOR indicator shows the same settings as in example #1, but notice the needle is no longer centered.  This means that the radial you are trying to fly on, 030, is now located to the right of the aircraft or the aircraft is to the left of the radial as shown in the illustration to the left.

To correct, you will have to turn right, perhaps 060 to get back on the 030 radial

Example 4:  To the right of a selected radial

Yet another VOR indicator shows the same settings as in example #1, but notice the needle is no longer centered.  This means that the radial you are trying to fly on, 030, is now located to the left of the aircraft or the aircraft is to the right of the radial as shown in the illustration to the right.

To correct, you will have to turn left, perhaps to 360 to get back on the 033 radial
 

Where Am I?

The steps necessary to estimate your position on a sectional chart include the identification of one or more VOR stations, then using your VOR indicator(s), you can triangulate your position in relation to the VOR stations.

Step #1:  Identify the VOR station(s) you want to use

On your sectional (or enroute) chart, find the VOR you want to navigate with.  Shown in the figure below is the Linden VOR.  As can be seen in the small box that contains the name Linden, you will see a frequency of 114.8.  With your NAV radio:

  1. Dial in the 114.8 frequency

  2. If equipped, press the toggle button to move the stand-by frequency 114.8 to the active frequency

  3. On your COM stack, select the NAV radio and if necessary, pull-out or press the squelch button on your NAV radio. 

  4. Listen for the VOR station's Ident code

Step #2:  Find your position relative to the VOR selected

There are two ways to do this:

  • Turn your OBS so the word 'TO' is shown in the direction window in the OBS and the  needle is centered.  At the top of the OBS, you will see the course you will use to fly TO the station, and at the bottom is the radial you are currently located on for that VOR.  In this case, if you fly about 048 (top of the OBS), you will fly directly TO the Linden VOR (notice the TO indicator near the bottom of the OBS).  Looking at the bottom of the OBS, you will see about 228, this is the Linden VOR radial you are currently located on.   So, you are to the south-west of the Linden VOR (228 degrees).

- OR -

  •  Turn your OBS so the word 'FROM' is shown in the direction window in the OBS and the needle is centered.  At the top of the OBS you will see the radial you are on, and on the bottom you will see the course you will use to fly TO the station/  In this example, you are currently located on the 228 radial (top of the OBS) because the FROM indicator is shown near the bottom.  To fly TO the station, look at the bottom of the OBS and you'll see a course of about 048.  To fly to the station, simply turn to that heading.

 

So, using either of these methods, we now know that we are on the 228 radial (south-west) of the Linden VOR.

Step #3:  Find your distance to the VOR

If you have a DME receiver in your aircraft, you can dial in any VOR station that also has DME capabilities to see just how far away you are from the VOR.  With the radial information and distance information, you can tell exactly where you are in relation to the VOR.  As shown here, you are 15.3 nautical miles from the VOR on the LIN 228 Radial. 

Step #4:  Triangulate with another VOR

If you have 2 NAV radios (or even one with a little slight of hand), you can triangulate or find 2 radials whose intersection is your exact location.  Here's how you do it.

  1. Dial in your first VOR station (we'll use the example of step #2).  Turn the OBS to get a From indicator with the needle centered

  2. Dial in your second VOR station in your NAV 2 radio (don't forget to identify the station).   In this case, we picked 116.00 for the Manteca/ECA FOR.    Turn the OBS to get a FROM indicator with the needle centered on the second OBS.    As can be seen here, you are currently on the 304 degree radial from the Manteca (ECA) VOR station.  This means, in relation to the ECA VOR, you are located North-West of the of the actual VOR transmitter located near Stockton California.

  3. With these two pieces of information, you can interpolate your position as shown below.

Flying TO a station

Turn your OBS so the word 'TO' is shown in the direction window in the OBS and the  needle is centered.  At the top of the OBS, you will see the course you will use to fly TO the station, and at the bottom is the radial you are currently located on for that VOR.  In this case, if you fly about 048 (top of the OBS), you will fly directly TO the Linden VOR (notice the TO indicator near the bottom of the OBS).  Looking at the bottom of the OBS, you will see about 228, this is the Linden VOR radial you are currently located on.   So, you are to the south-west of the Linden VOR (228 degrees).

 

Flying away FROM a station

Turn your OBS so the word 'FROM' (FR in this example) is shown in the direction window in the OBS and the  needle is centered.  At the top of the OBS, you will see the radial you are currently on and the course you will use to fly away from the station (at the bottom is the course you would use to fly directly to the station).  In this case, if you fly about 228 (top of the OBS), you will fly away from the Linden VOR.  This information also tells us that we are South-West of the Linden VOR.

 

Intercepting a Radial

If you are asked to intercept a radial and fly away from a station, the procedure that I describe here is very easy to follow.

  1. Dial in the VOR station you are being asked to navigate with.  Remember to identify the station to assure it is operational.

  2. Turn the OBS to the radial you are being asked to intercept by putting the radial to the top of the OBS. For the example shown here, we are using the Linden VOR.  The aircraft is currently on the 228 radial and is being asked to intercept the 270 radial from the station.

  3. Note the deflection direction of the needle.  It is showing a right deflection.

  4. Pick a course to fly.  Select a course on the top of the OBS in the direction of the needle deflection.  In this case, 270 - 360 are your choices.  Normally, you should pick something between these two extremes - about 310 degrees

  5. Turn the aircraft to this heading and wait for the needle to center

  6. Once centered, turn to 270 degrees and follow the radial away FROM the station.

Note:  It is very important that you don't think about this too much.  Trust your VOR indicator.  Set the radial you want to intercept, look at the deflection, pick a course, then fly that course.  If you think about the needle being deflected to the right, then thinking you must make a right turn, might and probably will, get you in trouble.

Intercepting a Bearing To

If you are asked to intercept a bearing to a VOR and fly TO the station, the procedure that I describe here is very easy to follow and much like that for intercepting a radial.

  1. Dial in the VOR station you are being asked to navigate with.  Remember to identify the station to assure it is operational.

  2. Turn the OBS to the bearing you are being asked to intercept by putting the bearing to the top of the OBS. For the example shown here, we are using the Linden VOR.  The aircraft is currently on the 228 radial and is being asked to intercept the 360 bearing to the station.

  3. Note the deflection direction of the needle.  It is showing a right deflection.

  4. Pick a course to fly.  Select a course on the top of the OBS in the direction of the needle deflection.  In this case, 360 - 090 are your choices.  Normally, you should pick something between these two extremes - about 045 degrees

  5. Turn the aircraft to this heading and wait for the needle to center

  6. Once centered, turn to 360 degrees and follow the bearing directly to the station.

Note:  It is very important that you don't think about this too much.  Trust your VOR indicator.  Set the bearing to the station that you want to intercept, look at the deflection, pick a course, then fly that course.  If you think about the needle being deflected to the right, then thinking you must make a right turn, might and probably will get you in trouble.

This page was last modified on 08/22/2009