Selected Course / DTK mismatch. (Annoyance)
Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=1080
Printed Date: 12 Mar 2025 at 5:13pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Selected Course / DTK mismatch. (Annoyance)
Posted By: comancheguy
Subject: Selected Course / DTK mismatch. (Annoyance)
Date Posted: 30 May 2016 at 6:41pm
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This is not a new occurrence. It has been happening since IFD-540 Install: Every few minutes, I get an alert message:  I can't figure out what the boxes want me to do? Now, I do have a "bootstrap" heading feed off of my DG. This tells the 540 what my heading is. This is supposedly very useful for the Stormscope. My best theory is that my whiskey compass is off by a few degrees, so that my heading (DG) doesn't match exactly what the GPS wants to see.  As you can see, I have the DG set to 082. What am I supposed to do, except cancel these alert messages every few minutes? I just flew from Annapolis, MD to Austin TX and back. Plenty of time to play with it. I have no idea. VERY annoying. But puzzling. Any thoughts?
Ken |
Replies:
Posted By: Gring
Date Posted: 30 May 2016 at 6:59pm
| Do you have a VOR indicator in the airplane? If so, is it a GPS enabled one like the Garmin 106? If so, you would need to set your course on the VOR indicator to 082. I don't believe the heading bug on the DG does anything back to the IFD540. |
Posted By: brou0040
Date Posted: 30 May 2016 at 7:32pm
| You also need to calibrate the CDI to the IFD540, which should have been done as part of the installation. |
Posted By: AUXAIR
Date Posted: 30 May 2016 at 8:27pm
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Gring is exactly correct. This message is generated when the OBS setting on the VOR indicator does not match the course that the 540 has as the desired track. Just turn the OBS to the indication given on the 540 and the message will blank. ------------- David E. Cessna 182 RG II |
Posted By: clydeps
Date Posted: 30 May 2016 at 10:20pm
| Another thing to check - make sure the IFD is set to use magnetic headings, not true. After some bench testing on one of my units I got that error in the plane, and it turned out to be because the tech had changed various settings, including changing the bearing reference from magnetic to true. It's in the User Options. |
Posted By: comancheguy
Date Posted: 30 May 2016 at 10:31pm
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Ok. 1) Mag not True 2) DO have two 106As. I think this must be the issue. (At least it makes sense. OBS was probably on 360. 3) MY DG Does, in fact, send the heading back to the IFD-540 4) CDIs have been calibrated. Thanks for the ideas. Ken
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Posted By: M20Kid
Date Posted: 01 Jun 2016 at 12:42pm
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My 540 was/is giving the same message. After I had the installer check, he found the CDI had been set 30 degrees off from the 540. However, even after that was set and confirmed I still get the pop-up message frequently. I just jiggle the CDI and the message may go away - or it may not. Mag not True may have been selected by the tech so that's a place to start. This is quite annoying and I hope it gets fixed quickly so I'm not chasing spurious messages. |
Posted By: comancheguy
Date Posted: 01 Jun 2016 at 12:57pm
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Since I had NOT been setting the CDI enroute, there may not be anything to fix. I need to go fly again. Ken
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Posted By: Gring
Date Posted: 01 Jun 2016 at 1:09pm
On #3, the DG may be sending your heading back to the IFD540, but that is different from sending the value the HEADING BUG is set to. The former you can only change by physically moving the airplane to a different heading.
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comancheguy wrote:Posted By: comancheguy
Date Posted: 12 Jun 2016 at 10:10pm
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So, I am 95% sure that this is, what you folks suspected. i.e.: Operator error on my part. I set VOR OBS to the heading and the messages seem to go away. I tested this today on a short flight. I just never bothered to do that, when navigating with GPS / GPSS. Thanks for the help! Ken
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Posted By: Gring
Date Posted: 13 Jun 2016 at 7:14am
| I see this a lot now that we've become so reliant on GPS automation. It is part of good discipline in flying. |
Posted By: teeth6
Date Posted: 13 Jun 2016 at 10:23pm
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I never see this on my top 540 because the HSI has autoslew but oddly enough, I never get the warning on my bottom 540 either which is tied to a different HSI. I would expect to see the warning when the HSI is not set to the correct heading but I do not. |
Posted By: OFD
Date Posted: 13 Jun 2016 at 11:54pm
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Personally, I gotta say that there are some times when I prefer to have the course set other than the desired track.. so these constant CAS msg's can be annoying.
Would be nice to be able to toggle them on/off.
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Posted By: DavidBunin
Date Posted: 14 Jun 2016 at 10:17am
Can you give an example? If we're talking about using a second VOR to monitor a crossing radial or something, then the second unit would be in VOR mode. If you're flying a GPS leg to a waypoint, why would you want the OBS set to a heading/radial other than in the direction of that waypoint? David Bunin |
Posted By: MysticCobra
Date Posted: 14 Jun 2016 at 12:16pm
Since that OBS ring doesn't actually affect the CDI's performance when the needles are being driven by the GPS, and the GPS display offers all the directional information you could want, the CDI's OBS ring is not a critical part of the navigational scheme. I have seen other pilots use it as a reminder for other thing's they're trying to keep in mind, like target altitude in a long climb or descent.
Personally, I spin the wheel to make the CAS message go away, but it does kind of feel silly to me sometimes.
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Posted By: brou0040
Date Posted: 14 Jun 2016 at 8:56pm
Do you have the units set to cross sync? If so, it would be really annoying to have to spin both CDIs for each waypoint, I'd think they'd be both using data from the #1 CDI.
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Posted By: teeth6
Date Posted: 14 Jun 2016 at 9:16pm
| They are set to cross sync but I always had to reset my #2 HSI to prevent the message with my 430s (which cross synced). Moreover, I still get that message occasionally but 95% of the time I don't despite not setting that HSI. |