Oh, I just noticed that there's nothing on DME!

 

I would add that at the end, discussing both the "slant-range" impact of your altitude on the range displayed, and the closure-rate for speed toward or way from the station, perhaps with both a cockpit panel and a top-down picture showing the path of flying a DME arc around a station, with a closure-rate of 0kts.

 

Here is a new version! I went to work immediately. I decided to make the first example a bit more simple, so only showing on which radial you are instead of showing triangulation. That's dealt with later on (although there it is used for finding an airport).

 

DME is mentioned in the tutorial (in the How to use VOR, A section, underneath the pictures) but since I want to focus on VOR itself, I will leave it at that. The things you mention are something for another tutorial, I think: a bit too advanced. And for newbies there already is more then enough advanced stufff That's why I also decided to leave out the bracketing bit: that's too much for newbies, I think.

 

NEW VERSION

 

Complete VOR tutorial

 

VOR stands for 'VHF omnidirectional range'. The VOR is like a wheel with 360 spokes. The VOR is in the middle and the 'spokes' always (and only) point outwards. Radial 090 always points to the east, radial 180 always points to the south and so on. When you are ON radial 090 you always are east of the VOR, when you are ON radial 180 you always are south of the VOR and so on. You can't be ON radial 090 west of the VOR or ON radial 180 north of the VOR!

The VOR only tells you where you are and not where you are going: you can be ON the 090 radial heading south or west or in any direction, so also towards or away from the station.

 

 

Tuning the NAV radio

Before you can use VOR you have to tune into the VOR station using the NAV radio. Check the MS Flight-map for all VOR frequencies. For this tutorial I will be using the RV-6A which has two NAV radio's and two related VOR gauges. They look a bit different but work in the exact same way. The main difference is that the VOR 1 gauge has a glideslope for ILS-landings on it (which we won't be using in this tutorial).

There is a knob on the right of the radio with two rings with which you can set the standby frequency: use the outer knob to set the number before the dot and use the inner knob to set the number behind the dot. Press the switch button (a little button with a two sided arrow on it) to make the standby frequency the active frequency. You can click on the Ident button (underneath the switch button) to hear the morse code (also see the map for those) that every VOR emits: it's always good to verify you are tuned in to the right VOR. Click the Ident button again to turn the morse code off.

 

Beware that VOR only works within a certain distance and there has to be a line of sight! So you might not get contact with a VOR until you are close enough or until you are at a certain altitude! Mountains can also block VOR signals. When you are flying straight over a VOR you also won't have contact with the VOR for a short while in what is called 'the cone of confusion': that cone is wider the higher you fly.

 

 

 

 

OBS

You can select a specific radial to 'work with' using the OBS (which stands for 'omni bearing selector') on the bottom left of the VOR gauge. The number at the top of the VOR-gauge shows the currently selected radial. (Since there obviously always is a number at the top of the VOR-gauge, there always is a radial selected.) However, in some situations the top of the VOR-gauge will show you the 'reciprocal' of the radial you are working with, meaning the opposite one. More about that later.

 

CDI

The VOR gauge has a needle that can move left and right: that's the CDI, which stand for 'course deviation indicator'. When used properly, the CDI will tell you if you are on course or not. When you are on course the CDI will be centered: if the CDI is deflected left you need to move your plane to the left until the CDI is centered again and if the CDI is deflected right you need to move your plane to the right until the CDI is centered again. This always works this way if your current heading is about the same as the heading you see on the top of the VOR-gauge (the selected radial). If you don't do that and fly the opposite way, you will get reverse sensing. More about that later also.

In the middle of the VOR gauge you also see a row of dots: every dot stands for 2 degrees deflection. The middle dot is a circle: the outside of that circle is also 2 degrees. This helps you to see how many degrees the CDI is deflected (or how many degrees you are off course).

 

TO/FROM

You will also see TO or FROM being activated. When used properly, TO and FROM will show you if you are flying TO a VOR or FROM it, but the TO and FROM indicator actually tells you where you are in relation to the selected radial: you are either on the half of the 'VOR-circle' where the selected radial is (the FROM side, with the selected radial in the exact middle) or on the side of the 'VOR-circle' where the selected radial is not (the TO side). In other words: the FROM side runs from +90 and -90 degrees from the selected radial: the TO side consists of the remaining 180 radials.

The line where FROM goes to TO is called 'the line of ambiguity': it always runs perpendicular to the selected radial, so it's formed by the radials +90 and -90 from the set radial. Knowing this is good for your situational awareness. When you are flying using VOR and you see TO suddenly go to FROM, you know you have passed that line of ambiguity and you also know exactly on which radial you were when that happened (the one +90 or -90 degrees from the selected radial).

Beware that the TO FROM indicator does NOT always simply point to the VOR station!

 

How to use VOR

 

A. Where am I in relation to the VOR-station?

In other words: ON which radial am I? Turn the OBS until the CDI is centered and FROM is activated. The number at the top is the radial you are on.

 

Example:

 

 

And this is how the above situation will look like on the Flight map (I added the radial and VOR information to it).

 

 

Underneath the second radio you will see the DME, which stands for 'distance measuring equipment'. A lot of VORs also have DME and this device will show you the distance to the active VOR and the speed at which you are moving towards it or away from it. This helps you to get an even more precise indication of your current position.

 

You can also use two VORs to figure out your EXACT position: figure out on which radials you are of both VORs and then draw those radials as lines on the map (in your mind or on an actual paper map): where the two lines intersect is your EXACT position.

 

B. How to fly straight to a VOR

Turn the OBS until the CDI is centered and TO is activated. The number at the top is the bearing you need to fly to get to the station. The bearing is the heading you need to fly towards the VOR but the actual heading may be slightly different due to wind. (When flying inbound you talk about 'bearing', when flying outbound you talk about 'radial'.)

 

In fact, that number always is the reciprocal of the radial you are actually ON, so the opposite radial! (The number of the reciprocal always is the number of the radial you are working with minus or plus 180. Quick tip if you're not too good at math: radial - 200 + 20 = reciprocal, or: radial + 200 - 20 = reciprocal.)

When you fly towards a VOR, you always use the reciprocal for navigation. Why? Because only this way you can follow the CDI left and right. For proper usage of the VOR you should always make sure your heading is about the same as what the VOR gauge shows you. If you don't take note of this and you are flying the opposite heading of what the OBS is set to, you will get 'reverse sensing' which means that when the needle goes left you have to move right in order to center it again! Try to avoid that situation!

So turn your plane to that bearing, keep the CDI centered and you will fly straight toward the VOR. Do not constantly 'chase the needle': if you see the CDI is moving to the left, do not make huge turns to get back on course, but slightly turn to the left until you see the CDI moving to the center again. When it is centered again, make sure you are flying the desired heading once more or the CDI will move sideways again.

 

The spokes of a wheel get closer and closer to each other the more you get to the center of the wheel. This is also the case with VOR: this means that the closer you get to the VOR-station, to more sensitive the CDI will become. When you are almost there the CDI will usually deflect completely: simply keep flying the desired heading and do not 'chase the needle'. When you are almost above the VOR station TO will be off very briefly and then it will be switched on again, showing FROM: this means you have passed the VOR and you are on the side of the selected radial: the reciprocal radial has become the current one.

 

Example: you are flying ON the 090 radial towards the VOR so you have the OBS set to 270, the reciprocal. TO is activated and your heading is 270. Once you pass the VOR you actually are ON the 270 radial, FROM will be activated and your heading will still be 270.

 

C. Intercepting a radial

Every now and then it is required or convenient to fly on a specific radial. You can do so towards or from a VOR station.

The following (specially the inbound part) may look a bit complicated but that's because I explain how to intercept a radial in a situation where you don't really know where you are. Usually you would plan a flight and make sure VORs and radials are connected in a logical way. But just in case you get orders to suddenly intercept a given radial, I will give you the complete story.

 

To fly away (outbound) from a station on a specific radial: turn the OBS until the desired radial is at the very top.

 

- If FROM is activated, look at the CDI and move left or right until the CDI is starts to center. Usually you would intercept the radial at an angle of 45 degrees. Example: you are left of the 270 radial: fly a heading of 315 to intercept the radial. Make sure that when you actually intercept the radial your heading is the same as the radial itself. You need to turn into the radial, so to speak.

 

- If TO is activated that means you are on the wrong side of the VOR (not the half of which the desired radial is the middle one), first fly the heading of the radial regardless of what the CDI shows you. When TO changes to FROM (and you have passed the line of ambiguity and hence you have passed the VOR (not necessarily flying directly over it!) proceed as described above.

 

Example:

 

 

 

 

To fly towards (inbound) a station on a specific radial: first you should figure out which radial you are currently on (see above): you have to know where you are in relation to the VOR because you can't intercept an inbound radial from the wrong side...! It's most convenient if you use one VOR to figure out on which radial you are and the other VOR for the actual interception!

 

1. If you are within 30 degrees of the desired radial, turn the OBS to the reciprocal of the desired radial: you will see TO being activated. Intercept the radial at an angle of 45 degrees (just as described above) and fly towards the VOR.

 

2. If you are between 30 to 60 degrees of the desired radial, turn the OBS to the reciprocal of the desired radial: you will see TO being activated. Start intercepting the radial at an angle of 90 degrees. When you get closer to the radial, check again on which radial you are (as said: you could use the other VOR gauge to do so!): as soon as you are within 30 degrees of the desired one, proceed as described in step 1.

 

3. If you are between 60 to 90 degrees of the desired radial, turn the OBS to the desired radial (so not the reciprocal): you will see FROM being activated. Fly the heading of the radial (so away from the VOR) for 2 minutes. Check your position again (which radial you are on) and repeat the step until you are within 60 degrees of the desired radial: then proceed as described above (step 2 or 1).

 

4. If you are more then 90 degrees from the desired radial you are 'on the other side' of the VOR (in relation to the radial). Turn the OBS to the desired radial: you will see TO being activated. Fly the heading of the radial until TO changes to FROM. You will then have passed the line of ambiguity and hence you have passed the VOR: you are on the good side now. Keep on flying that same heading for 3 minutes and then check your position (which radial you are on). Proceed as described above, depending on where you are (step 3, 2 or 1).

 

D. Triangulation: how to get anywhere with the use of VOR

Now you know how to intercept radials inbound and outbound, you can use two VORs at the same time to get you anywhere you want to, for instance to an airport that has no VOR nearby. If (for example) an airport has two VORs close enough to get in contact with, there always will be TWO radials (and no more) that will intersect at that position! If you would have a map you could draw a line from the center of one VOR to that airport and then draw another line from the center of the other VOR to that airport. Those two lines are the radials you need and where the lines intersect is where you have to fly to!

 

 

If you don't have a map you could find the radials you need on the internet. For instance go to http://www.airnav.com/airports/ and search for the airport you want to fly to. Usually you will find a section called 'Nearby Radio Navigation Aids'. Simply pick two VORs to use: if there are more options pick the ones which have radials that are perpendicular to each other because that makes finding your destination easier.

 

 

Start the flight and set up both VORs. Pick ONE radial that you want to intercept first: usually when looking at the map it's pretty clear which radial is closest or easiest to intercept. Make a note of which radials has to be flown outbound or inbound: you might want to use the reciprocals of the radials in order to get where you want to get!

Once you have intercepted one of the radials keep the CDI centered: all you have to do now is wait for the other CDI to center also. When BOTH CDI's are centered you are on the intersection!

 

Intercepting one radial and then waiting for the other to center isn't the most cost effective or shortest way of getting to your destination: you might also want to aim right at the intersection, so intercept the radials not until you are at your destination, but that's quite hard to do and so I always pick one radial. I do however plan WHERE I want to intercept that radial: usually I simply figure out a heading to fly that should take me to an intercept point that's pretty close to the destination instead of intercepting the radial right after take off. Obviously this all depends on how far the VOR and radial is from the departure airport.

Wow, the final version looks great guys.

Sometimes i try to teach people online while in Flight with use of the testbox, but it's much easier if they use this tutorial.

 

I think it's very important that enthusiasts learn about navigation, because it makes the flying much more rewarding and fun. If you can fly in IFR conditions like fog or heavy clouds or nightflying without the destination marker pointing you to your destination airport, a nice landing will be much more satisfying.

 

I know this guide is in the tutorial section, but i think it should be sticky right here!

Most new pilots don't even know the navigation instruments are actually working in MS Flight!!!

Thanks for the compliments.

 

It's good that you mention the tutorial section: I will update the tutorial over there!

 

BTW The tutorial as posted in my previous post has been submitted to the person who was interested: feel free to comment on it anyway, but the tutorial will be posted elsewhere as it is now.

 

About making it a sticky: hm, I think I will lock this one and post the finished tutorial as a new post (because by now this topic has several versions of the tutorial which may be confusing). If people are interested and want to talk about it, the topic will stay on the first page by itself, I guess. 'Stickying' my own posts (unless they are official mod messages) feels a bit weird...