VOR confusion preparing for test

[kgruber]

Exactly, yeah, it can be a bit confusing at first.

Has nothing to do with heading.

 

[Scotty78]

LORAN is all decommisioned now I think, though I still see people advertising them in airplane classifieds. "Hey everybody, the guy threw in this LORAN unit for free!"

 

[Palmpilot]

LORAN is all decommisioned now I think, though I still see people advertising them in airplane classifieds. "Hey everybody, the guy threw in this LORAN unit for free!"

I would consider that a necessary disclosure of a negative feature of the aircraft. It's equivalent to saying, "Be warned, there's a useless piece of junk in the panel, which you're going to need to pay someone to remove."

 

[ejensen]

Huh? LORAN is a ground based radio system that pretty much died back in the early 80s.

Nextgen will supplant all of the radio ground systems.

Loran went down early 2010 at least for the US.

 

[stratobee]

A VOR can stitch you up pretty bad when you're not flying in TO mode in general director of the radial. That's why the HSI was invented and it eliminates most of the confusion of a VOR.

 

[Palmpilot]

A VOR can stitch you up pretty bad when you're not flying in TO mode in general director of the radial. That's why the HSI was invented and it eliminates most of the confusion of a VOR.

One notable exception is that I've seen a pilot get really confused while trying to intercept a localizer when he forgot to rotate the OBS on an HSI to the desired course!

 

[dtuuri]

One notable exception is that I've seen a pilot get really confused while trying to intercept a localizer when he forgot to rotate the OBS on an HSI to the desired course!

That'll get you confused if the desired course is inbound on the back course.

dtuuri

 

[MAKG1]

One notable exception is that I've seen a pilot get really confused while trying to intercept a localizer when he forgot to rotate the OBS on an HSI to the desired course!

I've seen another pilot get real confused tracking the ILS OUTbound to the procedure turn at SNS.

 

[write-stuff]

I've seen another pilot get real confused tracking the ILS OUTbound to the procedure turn at SNS.

Say to yourself, "I am the needle. I am the needle." Well not you, but the pilot you were referring to.

 

[luvflyin]

Eh? LORAN is also an area navigation system like GPS. Different technology but by and large used the same way (you set waypoints where you want to go).
You can have VOR based area navigation as well (though the user interface is typically clunkier).

The biggest improvement is not the position source but the moving map which takes the a lot of the brainwork out of situational awareness. Eventide and others were doing moving maps long before GPS became practical.

It takes a lot of "awareness" out of situational awareness.

 

[luvflyin]

I'm gonna get a bag of popcorn and watch Gravity

 

[Omalley1537]

Sorry if I missed this in an earlier post-

To the OP, have you been taking flight lessons as well or just ground school? I did the latter and VORs made zero sense to me. 5 minutes into the first flight that we used them on, they were clear as day. I would highly suggest getting up with a CFI (if not doing so already) and playing with tracking VOR radials. If you are a hands on learner like me, you will save yourself a lot of head scratching and staring at textbooks.

 

[Palmpilot]

That'll get you confused if the desired course is inbound on the back course.

dtuuri

This was on a front course. Because he had forgotten to set the OBS, it looked like he was flying toward the localizer when he was actually flying away from it.

 

[FastEddieB]

Has nothing to do with heading.

Bears repeating.

What worked for me and my students on diagrams was to always mentally turn the little airplane to agree with what was in the OBS. That's the only way TO/FROM and LEFT/RIGHT made any sense at all.

When heading is given, it is almost always a distractor, except when they might be asking about a trend over time.

 

[Cap'n Jack]

Virtually all the time. It would be a VERY rare occurrence to not....approaching infinity.

Is it? Many victor airways are defined by 2 VORs. If you use the VOR in front of you and the one behind you, that is 2 VORs, isn't it? The only thing one can say is that they are somewhere on the airway, but not exactly where on the airway.

 

[coloradobluesky]

Do it by "quadrants". You have 4 possible quadrants. Figure out which one you are in. Work ALL the problems on the test prep that involve VOR's (and ADFs too if there still are any). Once you understand the quadrants, you are on your way to 'true' understanding of that curious VOR head.

 

[BillTIZ]

Just remember all radials radiate outward from the VOR.

Radial From, Bearing To.

 

[woodchucker]

Is it? Many victor airways are defined by 2 VORs. If you use the VOR in front of you and the one behind you, that is 2 VORs, isn't it? The only thing one can say is that they are somewhere on the airway, but not exactly where on the airway.

I would like to think that the implication was two VORs not on the same heading. A hiker without a GPS unit wouldn't mark their position on a topo map by recording compass headings of a mountain, and a taller mountain directly behind it.

 

[flyingron]

Huh? LORAN is a ground based radio system that pretty much died back in the early 80s.

So, I was addressing your comment that LORAN was somehow antiquated in that it lacked the ability to make a purple line on a moving map (which I presumed you meant GPS's area navigation facilities).

Nextgen will supplant all of the radio ground systems.

Umm, no, if it was NEXTGEN was going to do that, they wouldn't make it rely on a number of ground based radio systems. I suspect you meant that GPS was going to supplant ground-based navaids for enroute navigation. If so, then I'd agree.

 

[Cap'n Jack]

I would like to think that the implication was two VORs not on the same heading. A hiker without a GPS unit wouldn't mark their position on a topo map by recording compass headings of a mountain, and a taller mountain directly behind it.

I would like to think so too, but you'd be amazed at what people do. In the case I mentioned, the VORs are on opposite headings so it would be akin to a hiker determining their position with a mountain in front of them and one directly behind them.

You example is another case where one couldn't tell their position using 2 VORs. I suppose those that wrote the VOR area navigation programs had to consider those cases.

 

[Mistake Not...]

As an engineer, it's irritating this has to be this difficult.

A VOR (the hardware) gives you ONE THING. JUST ONE THING... the phase angle between two signals. If zero phase difference is alighed with magnetic north, then the phase angle corresponds to the magnetic bearing relative to the station.

All of the rest of this crap is due to the awful user interface designed to "help" me use that phase angle. I wish the VOR just had a numeric display of the phase angle. I honestly think that would be less confusing.

 

[MAKG1]

Bears repeating.

What worked for me and my students on diagrams was to always mentally turn the little airplane to agree with what was in the OBS. That's the only way TO/FROM and LEFT/RIGHT made any sense at all.

When heading is given, it is almost always a distractor, except when they might be asking about a trend over time.

It's a good way, but it's not the only way.

Another is, for VORs (not localizers), the needle picks left/right and the to/from picks top/bottom. The station bearing is then somewhere in the quadrant containing both (read the OBS ring).

 

[Mistake Not...]

The station bearing is then somewhere in the quadrant containing both (read the OBS ring).

Or, just read it from the numeric display. Oh, wait...

(Actually, a guy I know has a VOR head that displays the digital representation of the current bearing from the station (the radial), all the time. This should be a standard feature. The receiver already has it... that's all it has. All of the needle deflection and from / to crap are derived.)

 

[MAKG1]

Or, just read it from the numeric display. Oh, wait...

(Actually, a guy I know has a VOR head that displays the digital representation of the current bearing from the station (the radial), all the time. This should be a standard feature. The receiver already has it... that's all it has. All of the needle deflection and from / to crap are derived.)

That's what an RMI does (along with most glass panels, when the VOR is not selected as the CDI).

FYI, you'll make a whole lot less confusion if RADIALS come FROM the station, and BEARINGS go TO the station.

The exact bearing to the station is not relevant except if you are trying to fly directly to it. For cross radials, you want to know when you cross a specific radial, and whether it is in front of you or not. A simple digital bearing display isn't the best way to do that.

 

[dtuuri]

Or, just read it from the numeric display. Oh, wait...

(Actually, a guy I know has a VOR head that displays the digital representation of the current bearing from the station (the radial), all the time. This should be a standard feature. The receiver already has it... that's all it has. All of the needle deflection and from / to crap are derived.)

I used to fly a Citation II with a Bendix RNS 3500 RNAV. The CDI was absolutely worthless on these models and everybody with one soon threw it on the garbage heap for something else. Not me. Being cheap, even with OPM (other people's money), I simply used the LED readouts on the control head, exactly like you say. It worked fine that way for fifteen years.

dtuuri

 

[TangoWhiskey]

I know you already got your answer, but I want to jump in too! ;-) The water is warm, and I feel like swimming.

First of all, remember that a VOR "radiates" radials... radials never point TO a station, they emanate FROM them. That's why we talk about radials FROM and bearings TO. One is from the perspective of the VOR, looking out FROM, and the other is from the perspective of your plane, looking TOwards.

Can you join the 030 radial southwest bound? SURE! So, if you're told to join the 030 radial, first imagine that NE-heading line coming out of the VOR. If you're told to join the 030 radial SW bound, that same line extends out SW of the VOR and becomes the 210 radial on the SW side.

In general, for the information to make sense, and in order to avoid reverse sensing, the radial you have dialed in at the top of the OBS should match either the general direction you ARE going, or the general direction you WANT to be going. If you're not going that direction, you can just mentally picture the airplane going that direction, or draw it out on a napkin or a chart.

So to join the 030 radial southwest bound, dial in a SW (210) radial at the top of the OBS, and track to join it! If you're doing this from a point east of the VOR, flying say a heading of 360, you'll initially intercept the 030 radial, but you'll turn to a heading of 210 (+/- wind correction) and track SW bound on the 030 radial (with 210 still dialed into the OBS! Don't change anything! That's the direction you're headed!), with a TO flag, and it'll flip to a FROM flag and you'll be on the 210 radial as soon as you cross over the VOR (plus or minus the "cone of confusion" area, but you know what I mean!).

The To-From flag will simply tell you whether or not the selected radial WOULD take you towards the station, or away from it, IF you were flying the direction indicated by the number at the top of the OBS... but it doesn't care (or know about) what your current heading actually is.

Now, back to your original question... which referenced this VOR head image, what radial are you CROSSING was the question. Notice, it didn't say anything about what radial you are tracking... just which one were you CROSSING. I've set that scenario up below.

So let's look at this image, which has you NE of the station, the 210 radial dialed up on the OBS. The flag says the 210 radial would take you TO the station... that is, if you FLEW a heading of 210, which you're NOT, you're flying 096!

You can visualize this two ways; if you turned to a heading of 210 right now, tracking the 030 radial inbound on a 210 bearing to the station, you'd get correct left/right sensing, and the aircraft would be heading TO the station... until you get to the VOR, and then the flag would flip to FROM, because the 210 radial and 210 heading are now taking you FROM the station.

SMALL topic change. ;-)

Look at the image above once more. Imagine an airport is straight in front of you, and you're ten miles out from landing. You call CTAF, you'd report "10 miles west", correct? The easiest way to do that is to look at the BOTTOM of your heading indicator... it will always tell you were you are FROM the point in front of you (I use this trick all the time when making radio calls... am I south or southeast of the field? The bottom of the heading indicator will tell you, as long as you're headed to the field!).

Now, you can apply that SAME RULE to the OBS! If the 210 radial is dialed in, and the flag says that radial will take you TO the VOR, you must be in a quadrant to the bottom half of the OBS... you're somewhere NE of a 120/300 line. And if you imagine the VOR itself as the "donut" in the middle of the OBS, then you must be crossing the 030 RADIAL that RADIATES from the VOR, right? There's your answer!

Let's change our heading a bit, but nothing else:

Doesn't make any difference, you're still on the 030R FROM the station. Radials are ALWAYS FROM.

Put yourself on the other side of the VOR, totally different heading:

Now the flag says FROM, not TO, so the RADIAL FROM the VOR is indeed the number at the top of the OBS... you're crossing the 210 radial!

Hope that's clear as mud. You can play with it all you want here:

http://www.luizmonteiro.com/learning_vor_sim.aspx

 

[FastEddieB]

It's a good way, but it's not the only way.

Of course not.

It was just how I learned, and then taught, starting at Burnside Ott and extending many years thereafter with lots of students.

Anyway, it must have worked - I don't recall ever missing a question on any written about VOR indications.

 

[FastEddieB]

SMALL topic change. ;-)

Look at the image above once more. Imagine an airport is straight in front of you, and you're ten miles out from landing. You call CTAF, you'd report "10 miles west", correct? The easiest way to do that is to look at the BOTTOM of your heading indicator... it will always tell you were you are FROM the point in front of you (I use this trick all the time when making radio calls... am I south or southeast of the field? The bottom of the heading indicator will tell you, as long as you're headed to the field!).

That's exactly how I do it, glancing at the tail of the arrow on my vertical card compass. Otherwise, Mature Onset Dyslexia is sure to raise its ugly head!

 

[Caramon13]

...snip

So let's look at this image, which has you NE of the station, the 210 radial dialed up on the OBS. The flag says the 210 radial would take you TO the station... that is, if you FLEW a heading of 210, which you're NOT, you're flying 096!

You can visualize this two ways; if you turned to a heading of 210 right now, tracking the 210 radial (which you CAN DO from the NE side!), you'd get correct left/right sensing, and the aircraft would be heading TO the station... until you get to the VOR, and then the flag would flip to FROM, because the same 210 radial and 210 heading are now taking you FROM the station.

Areas of emphasis bolded. You can't track the 210 radial from the NE side, it doesn't exist. Radials are outbound from the VOR as you stated and do not go all the way through.

Not to nitpick but that kind of logic is going to confuse people big time. I used to think that way as well, but if you are NE of the station, the only radials that matter are the radials NE of the station, period. None of the radials SW of the station even exist for you. So saying you are flying on the 210 radial or can in any way shape or form BE on the 210 radial, is inaccurate.

If you flew a heading of 210 on the 030 radial inbound to the station, when you cross the VOR and the flip/flop happens assuming you do not alter your heading, you're now on the 210 radial outbound.

For me, I like to visualize the to/from indicator as a cone and I use the top of the VOR as outbound headings, bottom of the VOR are inbound headings. The opening of the cone shows me where I am.

So in your first picture, if I was to fly 210 so my DG matched what my VOR is showing, I would be 030 inbound to the station (opening of the cone pointing to 030 and 030 at the bottom of the VOR). If I rotated the OBS to have the 030 at the top, and turned the plane so that it matched the VOR I would be on the 030 outbound (030 top = outbound, flip flop would also show the opening of the cone pointed that way too)

In your third picture, it would be 210 outbound (210 top of VOR = outbound, from cone opening pointing to 210 radial so I'm southwest of the VOR).

With practice you can with accuracy of about 80 degrees tell exactly where you are in relation to a VOR without ever turning the OBS knob. Even with a full deflection of the needle.

 

[RotorDude]

A note regarding Loran's apparent demise.
For those who are not aware, it has been selected as the future backup system to GPS, with the idea being that GPS is very vulnerable to attack while Loran or eLoran (the modern incarnation) is much less so. You might not be able to complete your LPV to 200' with it, but will at least know where you are.

 

[dtuuri]

For me, I like to visualize the to/from indicator as a cone and I use the top of the VOR as outbound headings, bottom of the VOR are inbound headings. The opening of the cone shows me where I am.

Might be just me, but I'm having a tough time piecing together the parts of this puzzle:


dtuuri

 

[Caramon13]

Hah, well you got the cones right..

Here's a picture of what I'm talking about..it IS hard to verbalize without images.

To make these two work, the DG needs to match the VOR of course, that is, in both cases you need to be on a 210 heading.

Adding in some of the pics from luiz's page to help better illustrate..

 

[FastEddieB]

To make these two work, the DG needs to match the VOR of course, that is, in both cases you need to be on a 210 heading.

To be clear, all the indications would be identical, regardless of heading.

Except for the heading indicator, of course!

 

[flyingron]

And even for practical matters it's course not heading.

 

[Caramon13]

Right Eddie, heading (course, thanks Ron) doesn't matter although in this situation for making it easier to understand I just matched the two up. I could be on a 90 degree course in either case, in the exact same position relative to the VOR and the VOR indications will be identical.

The VOR indicator shows your position relative to it, it has nothing to do with where you're going or in what direction you're heading. It also doesn't show you how far away you are. So if I moved the plane CLOSER to the VOR or farther away along whatever radial it's on now the indications don't/won't change. Unless of course I'm REALLY close in which case it might be in the ambiguity zone.

 

[TangoWhiskey]

Areas of emphasis bolded. You can't track the 210 radial from the NE side, it doesn't exist. Radials are outbound from the VOR as you stated and do not go all the way through.

Not to nitpick but that kind of logic is going to confuse people big time.

You're correct, that would be better stated as "track the 030 radial inbound to the VOR from the NE, headed towards the 210 radial that continues outbound from the VOR to the SW."

I've edited my post to reflect this, for others that read it the first time!

 

[TangoWhiskey]

For me, I like to visualize the to/from indicator as a cone and I use the top of the VOR as outbound headings, bottom of the VOR are inbound headings. The opening of the cone shows me where I am.

Bravo! Beautifully simple. LOVE IT! THANK YOU. I'll incorporate that in future instruction / mentoring.

 

[TangoWhiskey]

Might be just me, but I'm having a tough time piecing together the parts of this puzzle:

View attachment 41490 View attachment 41488 View attachment 41489
dtuuri

Does this color coded explanation help? Try it with the other example pictures in this thread.

 

[Sundancer]

I remind myself that all radials are "from", and then my head clears.

 

[exncsurfer]

this is why they invented GPS,