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Deano777

VOR Problem

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Hi allI have always had an issue with my PMDG 747-400 where I cannot seem to get a CDI indication when in VOR mode, now either I am doing something really dumb (which is highly likely), or it just doesn't work.The following pics are an example of how my 747 is set up. I have tried several different VORs from around the world etc to no avail. This is certainly a problem when trying to conduct a VOR/DME approach (obviously).Pic 1 NAV/RAD setup, showing DTY VOR in the UK (116.40),fsscr003.jpgPic 2Shows the EHSI on the nav display with no CDIfsscr004.jpgAny ideas please?RgdsDean

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The ND is telling you that the station is 27nm behind you, and you are in LNAV mode. LNAV is not used for VOR navigation that I am aware of, in LNAV mode the system is flying to a waypoint in the FMS. I think that is why you don't see the CDI bar (course deviation indicator). Do a search on VOR Navigation in this section of the forum, I know it has been discussed at length on several occasions.

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DanThanks for the reply, I am a current airline pilot so I don't need any tuition on VOR navigation, the distance the VOR behind me is irrelevant, so is the fact that we are in LNAV mode. If I switch to HDG mode the CDI doesn't appear automatically.I am in LNAV mode but have the Nav Display set to VOR, it should show me a radial. What it should also give me is a raw data Relative Bearing Indicator pointing at the VOR. It isn't doing this.RgdsDean

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I did a search for you and found several threads including this one: http://forum.avsim.net/topic/118700-747-nav-radios/page__p__783272__hl__%22vor+navigation%22__fromsearch__1#entry783272I think using the intercept course to a waypoint method in the FMS is a quick way to use VOR-type navigation. Otherwise, I don't recall reading about a real world case where 747s navigate from a VOR.

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Cheers DanHowever, that is only someone's interpretation of how the IRUs pick up the aircraft's present position, which incidentally is correct. There still should be a way of flying using VORs as explained further down in the thread you posted.The 747-400 is 25 year old technology, if it cannot be done then how can we conduct a VOR/DME approach if the ILS is out? There has to be a way. Also when you select VOR to display on the EHSI it still should give a RB indication like an ADF needle.I'll have a trawl of the manuals to see what I can find.Thanks again.

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Pick the VORD approach from the approach list to set up the approach in the FMS.

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You should have raw data azimuth pointer/distance. When you insert a course into the nav/rad page for the required vor,I think you then get the CDI?The NAV RAD page is allows the crew tomonitor auto-tuning activity, or to manuallytune a desired frequency for VOR1/VOR2,ADF1/ADF2 or the ILS.A small ‘A’ next to a frequency indicates thatthe station has been auto-tuned fornavigation verification. An ‘M’ indicates thatthe frequency is manually selected by thecrew. Station identifier information appearsin the center of the display, along withcurrent redial TO the selected station.Likewise, desired OBS course for a VORcan be manually entered by up-selecting acourse from the scratch pad to either LSK2L or 2R.

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The "R" next to the frequency on the Nav Rad page shows that the frequency is Route Tuned. This is a form of autotuning carried out by the FMC. I recall (on the real aircraft), at least in the case of "A"utotuned frequencies, that the ND VOR page does not show the deviation bar or selected radial. If you manually enter the freq/course (assuming Route Tuning is manually overwriteable), you should get your proper displays : )VOR cannot be used as an autopilot mode (other than via LNAV). This applies to 747-400s, 767's, 757's and 777's. The age of the aircraft is not really relevant. Boeing designed it this way. The 737NG and Classic 737 seem to be the only current Boeings to be able to do this (not sure about the Boeing 717 (MD90)). A VOR must be manually flown when LNAV is not armed/engaged.Anyway, I'll see if I can simulate Route Tuning on a real aircraft when I get back to work (there are no route tuned dep/arr's at my local airport, but I'll try plugging one in for London Heathrow when I get back to work (to see what the displays look like)CheersQ>

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Anyway, I'll see if I can simulate Route Tuning on a real aircraft when I get back to work (there are no route tuned dep/arr's at my local airport, but I'll try plugging one in for London Heathrow when I get back to work (to see what the displays look like)CheersQ>
I simulated a Route tuned and a Procedure tuned VOR frequency on a 744 today. The Nav Rad page allowed for the entry of a manual course with each of these types of tuned stations (dashed lines were presented at LSK R2 and L2).Procedure&RouteTuning.jpgI have entered a CRS of "233" for the Procedure tuned station. When I did this, the Left ND VOR display showed the VOR scale and pointer (and would have showed the magenta deviation bar if the station had been in range).I don't know if this corresponds to PMDG ops or not(?)CHeersQ>
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DTY VOR is not identified. When identified it should look like this. 744c.jpgTuned Vor stations can be recognised by them showing their identifier instead of their frequency. So for some reason the airplane can not find the station. Can you audio-identify the DTY VOR?rgdsTom

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whats confusing to me is your screen shot. why arent you getting any raw data displays in the ctr mode, ie. vor needles? did you try tuning and identifying your vors to see if you get a morse code ident? looks to me like you have eveything correct. it almost seems like youre out of range of the service volume. if you go to map mode, do you see a green dashed line across your nd depicting your course?

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Chaps many thanks for your replies, and sorry for my late reply, I have been extremely busy at work.QavionThanks, this is my whole point, I am getting no magenta CDI needle at all, nor any relative bearing needles (which you should get too). Thanks for trying it out.TomI am aware that the 3 letter identifier will display when it is "working", but I am getting a DME distance readout, and I am getting a full morse IDENT resounding as well. What is also baffling me is in your picture you have the magenta CDI displaying, whereas if you look at post #8 from John Ellison it is stating that the 744 will not give you a CDI to navigate by. So how come you are getting one? I am perplexed to be honest.stebowAs above this is confusing too, I should at least get the relative bearing indicators in raw data from the VORs if nothing else, at the very least I can then fly the VOR as I do an NDB approach etc, but nothing. As I said above I am getting a DME readout though, and a full morse IDENT. Very strange.Anyway thank you all for your replies, it's much appreciated.

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Just today I was flying from Speterburg ULLI to Oslo ENGM. Leaving ULLI after take off my FMC radio autotuned two VOR wich suddenly makes me feel happy. as all you can see the ND shows the two green pointers indicating the position of both VORs (Pic01).

So i didn't resist to select the VOR display on the glareshield to see what happen. YES the the ND was showing the CDI bar on the old style rose hsi. 

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