What the heck is a VOR?
Very Old Rotor? Vittles On Range? Vultures On Reconnaissance? Nope. VOR is an acronym for Very high frequency Omni Range and is the backbone of air navigation currently in most countries. VORTAC is the same with TAC standing for TACAN, a military designation for its distance information on a VOR signal. VOR/DME is a VOR with Distance Measuring Equipment on site.
How does a VOR work?

The VOR works by sending out 2 signals, a reference and a phase, and the aircraft's receiver compares the time difference between receiving the signals to determine the radial it is on. The most common analogy used is the lighthouse. Assume the light takes 360 seconds to make one complete sweep. At 0 seconds the light begins it's rotation from north, at the same time a reference light goes off to indicate 0 seconds. Someone due east will see the reference light go off. 90 seconds later, he will see the rotating light sweep by. Someone due west will see the light sweep by 270 seconds after seeing the reference light. Of course, VORs work at a much faster rate than that. Now, imagine a VOR is a wheel with 360 spokes radiating out from its hub. The hub is the VOR station and each spoke is a radial. The "radials" radiate out from the center of the station and the VOR signal can be interpreted by the NAV radios to differentiate one radial from another over the 360-degree circle, providing azimuth information through the HSI. VORs are line-of-sight transmitters so surrounding higher terrain main block the signal, climb to 1000 AGL to pick it up.  

VOR on the Sectional

This is the Battleground (BTG) VOR we'll be using and how it appears on the Seattle Sectional. It's just north of Portland, Oregon. You'll see that the VOR looks a lot like a compass rose, a circle with station at its center and a single line pointing to magnetic north, this marks 000 or 360 degrees. Around its perimeter you'll see arrows every 30 degrees, and long and short tick marks every 10 and 5 degrees respectively.  

For this exercise we'll set the aircraft up at Fly for Fun Airport (W56) on runway 25, it's that magenta circle directly over the 120 degree arrow.



In the red rectangle you'll find the name of the VOR, its frequency, and the Morse code identifier that you'll hear if you've activated the audio for the nav radio tuned to and receiving this station.  The 360 or 000 radial shows the magnetic deviation at that lat and long. Don't worry about the Ch 113 that's military and we won't need it.



Each radial is referred to by its direction of emanation from the VOR.

The radial is based upon its position relative to the station NOT your aircraft. If you are exactly northeast of a VOR you are on the 045 radial. It does not matter which direction you are headed you are still on the 045 radial. The only other key piece of information is if you are inbound or outbound on the 045 radial. If you are heading away from the station you are flying outbound on the 045 radial and on a heading of 045. If you were heading towards the station on a heading of 225 you are inbound to the station on the 045 radial. Got it? To further illustrate, in the above figure the blue arrow shows inbound on the 180 radial, the orange arrow outbound on the 280 radial, and the red arrow shows outbound on the 45 radial.

Radio Navigation using the HSI

Bring up your Radio stack and tune your NAV1 standby receiver to 110.00 and press the STBY button. This frequency does not pick up any signal from VOR/DME's in the region.
Your HSI should look like this:



Now tune your NAV1 standby receiver to 116.60 and press the STBY (Standby) button to activate it. This frequency is for VOR BTG. From my current position the HSI and radio stack looks like this:



The Red Flag is missing from the HSI so it's receiving a signal. The Selected Course Pointer is pointing towards the VOR and as it is set towards the North it is the 180 degree radial that is currently selected. Note that the DME signal is showing that the distance to VOR is 4.7nm.

Now turn the OBS knob (bottom left knob with the yellow arrow) and see what effect it has on the Selected Course Pointer and the Deviation Bar. Continue turning the OBS knob until the Deviation Bar is aligned with the Selected Course Pointer.


Now you can see the VOR is at 300 degrees from our current position. This means we can state our exact position: 4.7nm on the 120 degree radial from the BTG VOR at 0ft AGL.

When the little white arrow shows up it means the NAV radio is receiving the signal and this can be verified aurally by the Morse code identifier when you click the NAV 1 button at the top of the radio stack. When it becomes annoying you can click it off too. That white triangle always points towards the VOR. When you're on the radial (needle centered) tracking inbound (going towards the VOR) it will point straight up. If you're tracking outbound (going away from the VOR) it will point straight down indicating that the VOR is behind you. If you are flying perpendicular to any radial it will point towards the VOR no matter what your heading is, or what radial you're intercepting. You will know you've intercepted that radial when you see the CDI center.



Remember your position is stated in relation to the VOR Not the VOR's position in relation to you!!


Let's make it just a little more interesting now. We are going to approach the VOR station using the 180 radial. Rotate the OBS knob to the left until the Selected Course Indicator is back on 360 degrees.
From here I'm going to fly runway heading until the Deviation Bar is in line with the Selected Course Indicator. Please note for this navigation you always fly towards the Deviation Bar. As you get closer to your radial intercept (turn point) the needle will start moving towards center.



When you get there your HSI and radio will look like this.




Now turn due North and track the radial keeping the Deviation Bar in line with the Selected Course Indicator and find the VOR/DME Station.

Radio Navigation using the VOR2

Now try flying the same exercise using the VOR2 Instrument (OBS 2) to understand the differences.

Reset your NAV1 frequency to 110.00 and ensure the NAV1 and NAV2 selector switch is turned off.

Your VOR2 Indicator should look like this:



Now tune your NAV2 receiver to 116.60 and press the STBY button to activate it and press the NAV2 selector switch.




Now twist the OBS knob until the Course Deviation Indicator is vertical, then twist the knob another 180 degrees and watch what happens to the To-From indicator. This is why:



The white arrow pointing upwards shows us the VOR's relative position to our current location, 300 degrees. The small yellow arrow pointing downwards shows us our current location relative to the VOR, 120 degrees.


Like we did with the HSI, we want to approach the VOR from the south, so rotate the OBS until North is at the top of the OBS and again you'll see something like this.



As we did with the HSI part of the course, fly runway heading until the Deviation Bar is in line with the Selected Course Indicator. Please note for this Navigation you always fly towards the Deviation Bar.

When you get to due south the Selected Course Indicator lines up vertically

Now turn due north and keep the Selected Course Indicator vertical. The dots at the bottom of the VOR2 indicator (5 each side) represent the number of degrees from your desired course. Each dot, left or right, represents 2 degrees.


Another Nifty VOR trick

Say you're looking for a small grass strip and your nearest VORs don't have DME.
Easy! Use your sectional to plot intersecting lines from 2 nearby VORs. Now record the headings back to where your intersecting lines cross the VOR circles and plug these figures into NAV 1 and NAV 2 radios. Track NAV1 radial outbound until NAV 2 centers and your field should be in sight.  

The following setup has a little twist so read carefully!

In this exercise we�ll be navigating to Sky Bryce strip to play a quick 18 holes at the nearby golf course or see if you can finally master the infamous Bunny slope at the nearby ski area depending on your season of choice. Yeah, I know it's a private strip but I promised him I'd be the only helo coming, oh well. The sectional shows Sky Bryce's field elev. to be 1263 MSL and its longest (and only) runway to be 2200 ft long.



We'll setup at Winchester Regional (KOKV) and fly direct to the LINDEN (LDN) VOR. Once there we will track outbound on the 273 till we intercept the KESSEL 163 radial this should place you right over the airport.

You'll see from the sectional that LINDEN's frequency is 114.3, punch that in on NAV 1 radio and hit the standby button to make it active. Now do the same thing for KESSEL (ESL), tuning NAV 1 to 110.8 and leaving it as the standby frequency.

You can go ahead and dial in a direct course for LINDEN by turning the HSI OBS knob till the arrow is up (showing TO the station) and the CDI (Course Deviation Indicator) is a straight unbroken line. This will give you your heading to the station (196 degrees).

Set NAV 2 to LINDEN also but its OBS to track the 273 radial.

Now take off from Winchester Regional on the active runway and once clear of the airport start tracking direct to LINDEN on the 196 that you set on the HSI.

Continue until you achieve station passage at LINDEN, signified by the flag going from TO to FROM and the needles on both NAVs going all squirrelly. DON'T CHASE THE NEEDLES!! Just go ahead and turn right to 273 degrees and wait for the NAV 2 needle to stabilize and make the small corrections to track the NAV 2 radial outbound.

Now while tracking outbound on LINDEN's 273, switch to the standby frequency on NAV 1. NAV 1 should now show 110.8 (KESSEL) and dial in the 163 radial on the HSI OBS knob.

Continue tracking LINDEN's 273 on NAV 2 till the CDI centers on the NAV 1 HSI and you should be right over the airport. Hey, I told you it was a neat trick. Now get out of there before the owner shows up.


Some hints: Try not to use the GPS, Map, FS Navigator, or the DME during this exercise unless you get incredibly lost. Try to set OBSs accurately and track them precisely. Print out the lesson and keep it handy. Use the landmarks on the sectional to help you during your flight. Rivers, towers, and roads showing up when and where they're supposed to is confidence building. The flight in the 206 shouldn't take more than 30 minutes including setup.  Good luck and have fun!!




For further study



                               Plotter

If you enjoyed this challenge you might wish to purchase a couple of sectionals and a plotter (like pictured above) and practice on your own. The plotter is the same standard scale as sectionals so you can compute distances and headings quickly. Often the local airport's FBO will give you out of date sectionals for free and plotters run $8-12US.