The big VOR topic

[Brett_Henderson 5]

Great thread .. great posts .. !

[enamel 4]

How are you guys determining what radials you need to follow? Paper maps and a protractor?

[Guest]

VOR/DME (and a lot more). Part 1: the preparation

 

On to the next example! This time I will be using triangulation to lead me to the IAF (Initial Approach Fix) of the ILS Y RWY 4R approach of Honolulu, which requires me to fly a DME-arc. I will be using three VORs and the ILS. I will show you how you can use the ingame Flight-map to figure out in which direction to take off for the best interception of the IAF. This example will show you that it's good to prepare and plan your flight so most of the thinking will be done before you even take off and you can spend most of your time to flying the plane.

 

The chart can be found here: http://155.178.201.1...4/00754IY4R.PDF but I will post a picture below of the part I am interested in for this specific tutorial.

 

BTW If you want to know how to read these kind of charts, check out this awesome and detailed explanation: http://www.navfltsm....om/ndb-appr.htm (Yes, it's about NBD-approaches but the information about the charts (or plates) is valid for all kinds of approach charts.)

 

Here is a picture of the approach I am going to fly. I will take off from Lanai Airport so I will be coming from the east. I will fly to the ALANA IAF which you can see at the bottom: it's an intersection of the MOLOKAI (MKK) VOR and the HONOLULU (HNL) VOR. The intersection is 13.9 nm from the VOR and I will have to fly an DME-arc (a very shallow turn in which I should keep a distance of 13.9 nm to the HNL VOR all the time) to where I can intercept the ILS.

 

 

The intersection is on the MOLOKAI 254 radial and the HONOLULU 171 radial. Now I could take of from Lanai, fly straight to the MOLOKAI VOR and then follow the 254 radial outbound. However, that would make the flight a lot longer then necessary. I rather intercept the 254 radial outbound a lot closer to the IAF itself. Lanai has a VOR nearby, LANAI (LNY) so I decide to use that one to get me close to the intersection. But... what radial should I use for that?

 

Here is a nice trick to figure that out by using the ingame Flight map. Point your mouse (the tip of the mouse arrow!) at the exact middle of a VOR and right click. Your plane will be positioned right above the VOR. Click on the plane and you will see a yellow circle. Point your mouse (again the tip of the arrow) exactly on the spot where the yellow line that points from the nose of the airplane crosses that yellow circle. Click and hold and drag: when you drag the mouse around you will see a number popup: that's the heading of the plane. Since you are straight above the VOR that will also be (approximately!) the radial of the VOR!

Now keep on holding down the mouse button and move the mouse in the direction where you want to go: you will see that even when you drag the mouse to another VOR or airport, you will still see that number of the heading/radial!

 

This is how I figured out where the MOLOKAI 254 radial and the HONOLULU 171 radial would intersect and how to appraoch it. (I combined all the following actions in one shot (I just love Photoshop) and drew lines on the map to make it visible, but in the game you simply have to remember the spot.) When I use triangulation I always pick one radial I am going to fly on and use the other only for checking if I am there yet. I placed the plane on the MOLOKAI VOR and after 'drawing' the 171 radial (red line on the screenshot) I placed the plane on the HONOLULU VOR to figure out where the MOLOKAI 254 radial would go (the other red line). Remembering the position of the intersection, I put the plane on the LANAI VOR to see what heading would bring me on a nice intercept line for the outbound 254 radial towards the IAF. (I drew a blue line to show you that line.) So... I decided flying outbound on the 280 radial would be the way to go!

 

(Sorry for this long explanation but once you get it, it's really quite easy Remember: what you see is the heading of the plane and not the actual radials, but it's close enough for planning a flight. Do not use this method for exact triangulation because it simply isn't exact enough for that).

 

 

Here I am on runway 21 of Lanai. As you can see I picked the RV-6A for this flight. Also because I think I like using two regular VOR gauges more then an HSI and a VOR, like in the Maule... but that's just me.

I already setup my navigation radio's. I didn't just do set the radio's in random order but carefully planned my setup.

- For the first part of the flight I will be flying outbound on the LANAI VOR 280 radial. I use NAV 2 (and VOR 2) for that. I set the radio to 117.7 and the OBS to 280. Why NAV 2? Read on.

- For the second part of the flight I will be flying outbound on the MOLOKAI 254 radial. I use NAV 1 (and VOR 1) for that. I set the radio to 116.1 and the OBS to 254.

- Later on I will have to use the HONOLULU 171 radial to know when I am at the IAF. So... I already set the standby freq of NAV 2 to 114.8 for that VOR! This way I won't have to look up and dial in that freq later on anymore: I can simply press the switch button on the NAV 2 radio, turn the OBS knob, and I am done!

- And as last I will use the ILS for runway 04R. I set the freq of the localizer (I-IUM, 110.5) as standby on the NAV 1 radio. When I am getting close to the approach I will only have to click on the switch button to make it the active freq and turn the OBS knob! As you can see... I made sure the ILS freq is used on NAV 1 because only VOR 1 has a glideslope indication!

 

So this is the reason why I fly the first part of this flight using NAV 2! During the flight I will only have to switch frequencies twice and use the OBS know twice: I won't have to dial in any freqs anymore and I will end up with using VOR 1 for the ILS landing! Always think ahead and carefully plan what you are going to do to keep the workload light during the flight!

 

 

On to the flight!

 

VOR/DME (and a lot more). Part 2: the flight

 

The LANAI VOR is close to the airport and in front of me. I have to intercept the outbound 280 so I decided to fly a heading of 235 (280 - 45) after take off for a nice intercept. Here I am flying on that heading.

 

 

Since the LANAI VOR station is very close, this intercept angle made the CDI zip by in a second or two, so I had to do some heavy cornering to get me back on track... Anyway, after a while I was flying on the 280 radial, using VOR 2.

 

 

On a sidenote: look at VOR 1 on the previous picture and on the picture below: as you can see TO went to FROM. What does this mean? This means that when that happened I passed the 'line of ambiguity' which is the line that runs perpendicular to the radial we use. Since VOR 1 uses the MOLOKAI 254 radial and I know I am south of it, I now know I just passed the 254 - 90 = 164 radial! When you look at the ingame map I posted above, you can see that should be somewhere between the A and I of LANAI.

This isn't important for this flight, but I simply like to watch that TO/FROM indicator to know where I am. It gives you something to do...

 

 

After flying on the 280 radial for quite some time, the VOR 1 CDI starts to move. Here you can see I am about to intercept the MOLOKAI 254 radial! I will have to make a gentle turn left to a heading of 254.

 

 

And here I am on that 254 radial. Since I won't be needing the LANAI VOR anymore, I clicked on the switch button of the NAV 2 radio, which made the standby freq active, which was the one of the HONOLULU VOR. I then turned the VOR 2 OBS to 171, which is the radial which will tell us we reached the IAF. We only need it for that and won't be flying to or from it. Two actions was all this required because I planned ahead!

 

 

The VOR 2 CDI starts to move: we are close the the ALANA IAF!

 

 

Hm, okay, we just passed the IAF. The approach plate said the IAF is at 13.9 nm out and as you can see on the DME underneath the NAV 2 radio, I am at 14.3 nm... I am a bit too far away. I also should be at 3.000 feet but I am at 3.400 feet... Luckily the game has no ATC yet... Now all I have to do is to make a very shallow turn right to keep the HONOLULU VOR as close to 13.9 nm as possible.

 

 

Since I don't need the MOLOKAI VOR anymore, I click on the NAV 1 switch button to make the ILS freq active and set the OBS to 042, the inbound course of the ILS. Two actions and that's it! We can forget about VOR 2 now. As you can see the localizer is active already! I also am at the desired 13.9 nm from the VOR now. I am a bit too low now, but well...

 

 

As you can see on the approach plate I posted earlier in this post, I can start our turn at the 214 radial of the localizer. How do I know when I am there...? I have set VOR 1 to 042 already and I don't want to set it to 214 just to check where I am.

Now the reciprocal of 042 is 222 (as you can also see on the chart). 222 - 214 = 8. So we have to start the turn 8 degrees before we reach 042.

Look closely at the VOR gauge: you will see a little circle in the middle and 5 dots on each side. Each dot stands for 2 degrees and the outside of the circle is also 2 degrees. This means that when the CDI passes the third dot from the left we will be 8 degrees from our desired radial! Those dots aren't there just to make the gauge look pretty!

On this screenshot the CDI is at the third dot, so I start the turn.

 

 

Now I don't know which moron decided that radial 214 was a good spot to start the turn, because for ME this was way too close to the radial so I completely overshot it. Anyway, after some heavy pulling on the joystick again, here I am flying exactly on the localizer and glideslope. (Don't you think I flew the entire approach which such a perfect cross on the VOR gauge...! I usually go up and down and left and right all the freakin' time! )

I am at 2.100 feet and at a distance of 6.1 which is just past a waypoint called PERLY (see the chart above). The approach plate shows I should be at 1.500 feet here, but I decided to simply follow the glideslope. But maybe I really should have been at 1.500 at PERLY for some reason...

 

 

And here is a final shot of the approach. More or less on track...

 

 

And that's it for today...

[Guest]

How are you guys determining what radials you need to follow? Paper maps and a protractor?

 

It depends. When I want to fly a real world approach I simply look at the approach chart for the radials. For very precise triangulation (like getting to an airport that has no VOR) I search for the relevant numbers on http://www.airnav.com/airports/ And for less precise directions I simply use the ingame Flight map (like I explained in the example above).

[RoboRay 126]

How are you guys determining what radials you need to follow? Paper maps and a protractor?

 

I use an actual paper sectional chart and, because I can't find my protractor, a ruler. The chart shows a compass arc around each VOR station (circled in red, below), so any straight-edge will work.

 

 

I haven't been trying to do real-world approaches because I haven't felt like dealing with all the approach plates for "a game." :Waiting:

 

I may do that at one point, though.

 

I did annotate my sectional with the frequency and heading information for all of the ILS approaches in Flight, though, just to have the information handy and all on the same chart.

[Guest]

I use an actual paper sectional chart and, because I can't find my protractor, a ruler. The chart shows a compass arc around each VOR station (circled in red, below), so any straight-edge will work.

 

I haven't used that map yet myself because the compass is divided in steps of 5 degrees and it seems to me you can easily be 1 or even 2 degrees off... which can be the difference between finding your destination or completely missing it. But I suppose real world pilots use maps like these too, so if it works for them... Or do they use a map like that AND a protractor? I suppose so. You can't be precise enough in avation. x

 

You can download that map (28.7 Mb!) here btw:

 

http://aeronav.faa.g..._Islands_85.zip

 

EDIT

BTW I remember RoboRay posting somewhere that Flights uses an old VOR somewhere, so... always check if the flight you are planning can actually be done in Flight!

 

EDIT 2

I see now that some VOR compasses overlap on the map, making it impossible to figure out the right radial, so I guess a protractor is mandatory...? I think I will stick with the options I mentioned earlier...

 

EDIT 3

Planning flights with VOR in Flight is fun! It's some sort of puzzle you have to solve! If someone has a specific flight he or she would like to do and you can't figure out how to get it done, post your basic plan here and we (everyone here including me) might come up with various 'solutions'. Fun!

[Propane 16]

I haven't used that map yet myself because the compass is divided in steps of 5 degrees and it seems to me you can easily be 1 or even 2 degrees off... which can be the difference between finding your destination or completely missing it. But I suppose real world pilots use maps like these too, so if it works for them... Or do they use a map like that AND a protractor? I suppose so. You can't be precise enough in avation.

 

Those couple of degrees (usually) won't be of live and death importance. Take a look at the 1 in 60 rule of thumb; if you fly 60nm with one degree of deviation, you'll end up about 1nm off track. Flying the same distance with 5 degrees deviation would put you 5nm off track. Generally speaking, that should be within visible range... Unless the visibility is really low of course, but then you should ask yourself if it's still safe to go to that small airport that doesn't have instrument procedures or radio navigation aids :P.

 

About using the protractor... I personally always plan my VFR flights with a chart and protractor, but once you're up in the air you don't want to fumble around with both of those at the same time unless you really have to, or if someone else can take over control. It's aviate, navigate, communicate. If you need two hands to deal with the map and protractor, there are no hands left of the controls ;). Even if you only need one hand because you've got the map fixed to a kneeboard, you still need to look away from what you're doing quite a lot if you want to be accurate. So estimates usually suffice. By crosschecking along the way you can always finetune. Your last point about being precise is very much true though.

[RoboRay 126]

I haven't used that map yet myself because the compass is divided in steps of 5 degrees and it seems to me you can easily be 1 or even 2 degrees off... which can be the difference between finding your destination or completely missing it. But I suppose real world pilots use maps like these too, so if it works for them... Or do they use a map like that AND a protractor? I suppose so. You can't be precise enough in avation. x

 

Nah, it's pretty easy to measure with a precision of +/- 1 degree (at least, on the ground). With a one degree error, 60 miles away from the VOR station, you're still only one mile off your track. I'm sure you can see the destination from there. :Peace:

 

In fact, your OBS is only calibrated to a precision of +/- 2 degrees. The stations themselves aren't perfect, either. I believe the FAA requires them to be within +/- 3 degrees. So, no matter how accurately you measure things, there's still going to be a bit of real-world fudge factor. I'm sure everything is perfectly calibrated in Flight, though.

 

EDIT

BTW I remember RoboRay posting somewhere that Flights uses an old VOR somewhere, so... always check if the flight you are planning can actually be done in Flight!

 

Yes, that was the Kona VOR. Flight uses the old location a few miles south of the new one. The current charts show the old VOR station's location, so they're useable with a protractor, but be aware that the compass circle on the new chart is in the wrong spot.

 

EDIT 2

I see now that some VOR compasses overlap on the map, making it impossible to figure out the right radial, so I guess a protractor is mandatory...?

 

Yeah, pretty much. I'm still looking for my old one. The circles are great for when you're in the air and need to estimate because you don't have enough hands to fly and do a measurement, but proper flight-planning requires the correct tools.

[Guest]

Thanks for the additional info, Intrance and RoboRay! I understand that 1 degree or even more isn't that big of a deal.

 

However, you both didn't take into account my (and I guess (or hope) I am not the only one) inability to fly right on the radials and the way some of those small airstips are hidden in the scenery as if they don't want anyone to land on it! It's not unusual for me to be flying one or two degrees beside the actual radial I should be on and I have flown right over some airstrips without ever seeing them...!

[RoboRay 126]

Thanks for the additional info, Intrance and RoboRay! I understand that 1 degree or even more isn't that big of a deal.

 

However, you both didn't take into account my (and I guess (or hope) I am not the only one) inability to fly right on the radials and the way some of those small airstips are hidden in the scenery as if they don't want anyone to land on it! It's not unusual for me to be flying one or two degrees beside the actual radial I should be on and I have flown right over some airstrips without ever seeing them...!

 

I hope you're not disappointed if I tell you that many real-world pilots suffer from the same problems.

 

Heck, I've even had to drop down low and read town names off water towers once or twice! :Loser:

 

That was when I was doing some Special IFR... You know, "I Follow Roads."

[Guest]

I hope you're not disappointed if I tell you that many real-world pilots suffer from the same problems.

 

Heck, I've even had to drop down low and read town names off water towers once or twice! :Loser:

 

That was when I was doing some Special IFR... You know, "I Follow Roads."

 

:LMAO:

 

BTW I certainly am not disappointed: on the contrary, I am happy because now I feel even more like a real world pilot while flying in Flight.

[sightseer 895]

Did ya'll have to do anything (like complete a mission or something) to get NAVAIDS to show up on your map?

 

I have no NAVAIDS on my map. Am I the only one?

[staib 1]

There IS an option on the map screen ( or options?) to display Navaids. They are OFF by default.

 

Sorry but I'm away from my PC now, and can't exactly recall the command but if you don't find out how I'm sure someone else will step in...

[RoboRay 126]

Did ya'll have to do anything (like complete a mission or something) to get NAVAIDS to show up on your map?

 

I have no NAVAIDS on my map. Am I the only one?

 

You have to select them under the Legend menu on your Map screen. After that, they'll show up along with the airport info. However, I don't believe they are visible when zoomed all the way out... You have to zoom in a little to see them, just like some of the small airports don't show up until you zoom in closer.

[Sigma54 0]

I've prepared a brief tutorial on how to use Google Earth to find VOR radials. Hopefully it helps someone!

• Download and install Google Earth from earth.google.com (the full program, not just the browser plugin)
  
• Open up Google Earth
  
• Deselect all unwanted markers in the Layers section in the bottom left corner. I unselected all of them except for borders. You can leave them on but then the view becomes very cluttered.
  

 

 

• Open the VOR and Hawaii Airports kmz files from Google Earth
  
• If you opened the VOR file second, it will center you on Northern Switzerland. Double click on the Hawaii Airports folder and it will recenter on Hawaii.
  

 

 

 

 

 

 

• Zoom in on the area you wish to travel through. Find the most appropriate VOR (probably closest one but must also be in line of sight – not blocked by mountains)
  
• In this case, I’ve zoomed in on the Hilo VOR ITO. By clicking on it, it will give the radio frequency and the magnetic deviation.
  

 

 

• Let’s assume I want to travel from the ITO VOR to Pepeekeo airstrip. To find the appropriate VOR radial and approximate DME, select the Ruler tool, and draw a line from the VOR to Pepeekeo.
  
• The ruler screen will give a length (you can change it to show Nautical Miles) which should be approximately equal to the DME reading at Pepeekeo from the ITO VOR which in this case is 9.4 NM.
  

 

 

• It also gives a heading. However, this heading is based on True North and not Magnetic North so if you follow that radial, you will be off track somewhat (depends on how far you’re going and also the magnetic deviation at that location).
  
• VORs are based on Magnetic North. To convert the value given by Google Earth to a VOR radial, you need to subtract VOR’s magnetic deviation from the heading determined by Google Earth if the deviation is East, otherwise, if the deviation is West, you need to add them together. In this case, the ITO VOR magnetic deviation is E9.549° and 322.73°-9.549° = 313.18°.
  
• Therefore, to get to Pepeekeo from the ITO VOR near Hilo, you would follow radial 313 for about 9.4 NM.
  

 

Here is a top-down view of Pepeekeo Airstrip as it isn't very easy to find from the air!

 

 

Additional Info:

• There is a Magnetic Course to True Course converter (as well as the reverse) at http://www.luizmonteiro.com/Wind.aspx
  
• There is a search bar in Google Earth which can help in pinpointing your destination if you don’t know where it is on the map.