VOR Navigation Issues

[bluepilot76 0]

Thats a good answer, but I think the OP is having to navigate OUT on a specific radial for a certain distance (probably it defines the airway) to the half way point, and then navigating IN on the second VOR.

 

 

e.g. I would expect (in RL) that I could dial in (for example) the 330 radial which might define a particular airway. I would head NW along that radial and at the half way point tune in the VOR at the other end of the segment and come IN along the 150 radial. In RL for the VORs would be close enough (if they were defining a airway segment) such that the difference in magnetic variation between them was negligible.

 

Tried to download the .zip but it wouldnt

[SteveW 1,792]

as you move along any line between any two waypoints the compass direction to/from the waypoints changes with your movement

[Guest]

Thats a good answer, but I think the OP is having to navigate OUT on a specific radial for a certain distance (probably it defines the airway) to the half way point, and then navigating IN on the second VOR.

 

e.g. I would expect (in RL) that I could dial in (for example) the 330 radial which might define a particular airway. I would head NW along that radial and at the half way point tune in the VOR at the other end of the segment and come IN along the 150 radial. In RL for the VORs would be close enough (if they were defining a airway segment) such that the difference in magnetic variation between them was negligible.

 

The problem is that the OP isn't using (specific) radials but headings that come from a planner. In your example, when flying towards a certain airway, you would use published numbers to get there: an airway is specified and known and documented. You never try to fly to an airway or an intersection using headings you figured out yourself as the OP is trying to do (afaik). That won't work.

Also, figuring out where a specific point is in 'space' will lead to different results depending on where you are when you calculate that point.

And finally, "the difference in magnetic variation between them was negligible" doesn't apply when flying towards specified intersections or known points of triangulation because the people who published those numbers took note of magnetic deviation, so if for instance an approach chart says an approach fix is at a certain point where two radials intersect, you can be sure they numbers are 100% correct. :wink:

[bluepilot76 0]

 

And finally, "the difference in magnetic variation between them was negligible" doesn't apply when flying towards specified intersections or known points of triangulation because the people who published those numbers took note of magnetic deviation, so if for instance an approach chart says an approach fix is at a certain point where two radials intersect, you can be sure they numbers are 100% correct. :wink:

 

Yeah thats what I meant, but not in so many words.

 

If the OP is using the headings he calculated then that would be the source of the problem, but I was giving him more credit than that. It sounds to me like he knows very well what radials are supposed to intersect to define his airway.

 

Maybe I have misunderstood.

[Guest]

Yeah thats what I meant, but not in so many words.

 

If the OP is using the headings he calculated then that would be the source of the problem, but I was giving him more credit than that. It sounds to me like he knows very well what radials are supposed to intersect to define his airway.

 

Maybe I have misunderstood.

 

Or maybe I have misunderstood. :wink:

[TChapman500 0]

Tried to download the .zip but it wouldnt

Fixed it.

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Again, don't use the flightplans headings but use the CDI to get to the VOR

What is CDI?

 

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When you navigate using VOR you have to actually USE them and not rely on headings calculated in a planner. Use the VOR the way it is intended and not only as some kind of landmark to fly towards using calculated heading without actually using the radials of the VOR!

Huh? You're not making any sense! Do you even know what I mean by COURSE HEADING? It's the direction that the airplane flies to get to a specific point. NOT the direction that the nose is physically pointing towards! There are two heading selectors on the autopilot panel. One is the direction that the nose of the aircraft points to, and it's labeled "Heading." The other is the trajectory that the airplane flies, and it's labeled "Course." I put the headings listed into the flight planner into the selector labeled "Course." The HSI tells me that I'm on course, while the map shows that I'm on a ~5 degree trajectory to the right.

 

For the entire flight, outbound I'm drifting away from the course, inbound, I have to make a 90-degree turn to the left, then to the right, and now I'm drifting towards the course. The entire time, the HSI tells me that I'm on course.

[bluepilot76 0]

I reckon you should bin that flight plan. Dont try and emulate something from FS98 or whatever, life is complicated enough. Just get a new flight plan, a real one, use the VORs in FSX, and / or use the FMC. There are websites where you can download a real flight plan for the trip from Denver to Dallas or whatever your trying to do.

 

Real 737 pilot does not have a list of headings, at least not that he is actuallly following. He simply has a clearance; join airway ABC123 at intersection XYZ and leave at XZY. He is not flying around fiddling with the CDI. He is flying magenta line on his PFD. In fact the autpilot is doing it all in LNAV mode. So what your doing is not realistic for 737, after 200 series anyway.

 

I think you are being a bit rude to J van E, who is trying to help and has better things to do. He very well knows about courses and headings, he also knows what a CDI is.

[Guest]

Huh? You're not making any sense! Do you even know what I mean by COURSE HEADING?

 

LOL It would be a bit said if I didn't know the difference after 4,557 posts on this forum. :wink: I am just trying to understand what's going wrong with your flight. If time permits I will see what happens on my PC when I try to fly towards a VOR using the heading that a flightplan is giving me instead of using the VOR itself to get there. For now I will repeat again that it's a bit odd to tune into a VOR but to NOT actually use it but to use headings from a flightplan instead...

[mgh 89]

Do you even know what I mean by COURSE HEADING?

 

I don't. There is a course and there is a heading. There is such thing as a COURSE HEADING.

 

There aren't FS98 VORS in FSX either.

[TChapman500 0]

Bold texts indicate quotes from portions of the post.

 

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I reckon you should bin that flight plan. Dont try and emulate something from FS98 or whatever, life is complicated enough. Just get a new flight plan, a real one, use the VORs in FSX, and / or use the FMC. There are websites where you can download a real flight plan for the trip from Denver to Dallas or whatever your trying to do.

 

Real 737 pilot does not have a list of headings, at least not that he is actuallly following. He simply has a clearance; join airway ABC123 at intersection XYZ and leave at XZY. He is not flying around fiddling with the CDI. He is flying magenta line on his PFD. In fact the autpilot is doing it all in LNAV mode. So what your doing is not realistic for 737, after 200 series anyway.

 

I think you are being a bit rude to J van E, who is trying to help and has better things to do. He very well knows about courses and headings, he also knows what a CDI is.

 

"I reckon you should bin that flight plan."

What do you mean?

 

"Dont try and emulate something from FS98 or whatever, life is complicated enough."

That was my favorite flight in FS98.

 

"Just get a new flight plan, a real one, use the VORs in FSX, and / or use the FMC."

By use the VORs in FSX, do you mean the VORs that the FSX flight planner wants to assign me? What exactly do you mean by FMC? FSX just has a black screen-like object with a few dozen buttons below it for the flight management system.

 

"There are websites where you can download a real flight plan for the trip from Denver to Dallas or whatever your trying to do."

FSX compatible?

 

"Real 737 pilot does not have a list of headings, at least not that he is actuallly following. He simply has a clearance; join airway ABC123 at intersection XYZ and leave at XZY. He is not flying around fiddling with the CDI."

First, what is CDI? Second, what's the advantage for using these airways over the VORs with the in/outbound headings being put into the Course selector?

 

"He is flying magenta line on his PFD. In fact the autpilot is doing it all in LNAV mode."

There are some things about the autopilot that I do not trust. Non-VOR navigation is one of them.

 

"So what your doing is not realistic for 737, after 200 series anyway."

What I'm doing is exactly what I would do in FS98. The co-pilot would tune the NAV radios to the VORs, and input something into the course selector, and I'd follow the course indicated by the HSI. There were almost no course corrections after switching from the outbound frequency to the next inbound frequency.

 

"I think you are being a bit rude to J van E, who is trying to help and has better things to do. He very well knows about courses and headings, he also knows what a CDI is."

I'm trying to clear out what appeared to be contradictory instructions. And I was actually asking him what a CDI is.

 

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LOL It would be a bit said if I didn't know the difference after 4,557 posts on this forum. :wink: I am just trying to understand what's going wrong with your flight. If time permits I will see what happens on my PC when I try to fly towards a VOR using the heading that a flightplan is giving me instead of using the VOR itself to get there. For now I will repeat again that it's a bit odd to tune into a VOR but to NOT actually use it but to use headings from a flightplan instead...

 

 

"LOL It would be a bit sad if I didn't know the difference after 4,557 posts on this forum."

Sorry.

 

"I am just trying to understand what's going wrong with your flight."

When I put the headings into the course selector, I end up on a trajectory that is ~5 degrees off from where the map says I should be. And I'm trying to find a way to get the headings needed for the course selector right without having to repeat the flight several times and note down the new headings for the course selector.

 

"If time permits I will see what happens on my PC when I try to fly towards a VOR using the heading that a flightplan is giving me instead of using the VOR itself to get there."

Huh? I was using the VORs to get me there. The headings that I got from the planner are the headings I put into the course selector. I just left the heading selector to the default selection.

 

"For now I will repeat again that it's a bit odd to tune into a VOR but to NOT actually use it but to use headings from a flightplan instead."

What do you mean? I put all of the headings into the course selector. I was using the VORs exactly the way I'm used to using them.

 

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I don't. There is a course and there is a heading. There is such thing as a COURSE HEADING.

Thanks for clearing that up for me.

[SteveW 1,792]

try this fsx plan

 

FL340 400Kts

 

Waypoint Region Name Heading T(m:s) Total Leg(Nm) Alt(ft) Min Route

Airport KD KDFW 304.5 28:53 - 120.4 607 3000 -

VOR 112.70 K4 SPS 313.0 56:40 0:28 321.2 34000 6000 J168

VOR 116.90 K2 LAA 298.6 10:08 1:25 57.5 34000 18000 J52

VOR 112.10 K2 HGO 310.4 13:02 1:35 79.9 34000 18000 J52

Airport KD KDEN - - 1:48 - 5431 8000 -

 

regards

Steve

[Guest]

Ah, I think I am beginning to understand why I am confused... :wink: You are talking about headings from a flightplan all the time but you are using them as bearings (inbound to the VOR, where the 'heading' is the reciprocal of the actual radial you are trying to fly on) and (outbound) radials. But er... then I am back again with my remark that headings from a plan are something different then radials to get somewhere... LOL This is confusing (or is it just because it is late over here? :wink: )

The thing is that I never use VORs when I fly with GPS, I only use VORs when I don't use GPS: when I fly with VORs I use the CDI or HSI to fly directly to a VOR or to an intersection of two VOR radials in which case I always use information (radials) from official sites and NOT headings I figured out in a planner because they simply never match due to magnetic north deviations etc...

 

In other words: I never use headings from a flight plan as bearings to or radials from a VOR or to an intersection. When I use a planner to figure out on which two radials an airport is from two VORs, the numbers I get, headings from both VORs to that airport, never gets me there. The actual radials are always different, sometimes a few degrees, sometimes more then 10. So I keep on thinking your problem has to do with this magnetic north and so on... :wink: But maybe someone else can chime in?

[LAdamson 240]

Boeing 737-800. I compensated for wind direction. I'm talking about the course heading, not aircraft heading for the VORs.

 

The 737-800 uses GPS with backup GPS's as it's first line of navigation. INS is second, and then the VORs. Aircraft without GPS........as perhaps an older 767 will use INS, which is updated with VORs...........perhaps while taxiing at the airport.

[scott967 62]

Here is the problem (it is true to RL also): In FSX, your aircraft compass, and the courses or headings computed in the flight planner and the GPS are determined by the magnetic variation at the aircraft location. This is contained in a file magdec.bgl. IRL, magnetic variation is constantly changing with time. In FSX it is set by that file. The default file is derived from the standard US magnetic variation model which is computed at 5-year intervals, in this case 2005. There is an updated file around that uses the 2010 data instead.

 

Now so far, so good. BUT. VORs are set by FAA to magnetic north based on one of these 5-year models. FAA doesn't constantly adjust the VORs. Instead they only adjust the VOR periodically. Thus it is unlikely at any time that the radials from a VOR will exactly match the compass bearing from the VOR. In FSX the VOR magnetic variation is set on a per-VOR basis in the regional NVX files.

 

Look at HGO VOR which is in your flight plan. When I fly around HGO my compass is showing a magnetic variation of E 8.1 degrees. But when I look at the data in the NVX file, it shows HGO magnetic variation of E 12.0 degrees, almost 4 degree difference. What that means is if you are "on course" as shown in the GPS (303 course to the HGO VOR) when you set your VOR indicator (CRS knob on HSI or OBS knob on indicator) to 303, the needle will NOT be centered. Adjust the CRS knob and you see the needle centered at CRS 298 TO. So that is the setting you need on the HSI in order to properly follow the intended track.

 

Now you can confirm this by looking at the FAA low altitude enroute chart, L-10. It shows the V263 route from LAA to HGO as first 298 radial from LAA and then 118 radial from HGO, which of course is the same as 298 to HGO.

 

 

 

 

 

scott s.

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[TChapman500 0]

This green arrow on the GPS wouldn't happen to mean anything would it? I drew a line from the tail of the aircraft icon to that arrow and it appeared to be parallel to the course. I did not save any of the changes to the image.

 

Thanks for the info scott967. Very helpful.