Igor_U Posted July 5, 2022 Report Share Posted July 5, 2022 I have Garmin G5 (certified) installed in lieu of Attitude indicator and it's getting WAAS GPS signal from DTX 355 transponder (As well as it's dedicated dash antenna). Unit was calibrated for Attitude (pitch and rill) during the install and is quite accurate but it's GPS track displayed is 3-4 degrees off the old panel GPS navigator. Now, being new unit and such I would expect G5 to be accurate but recently, I paid more attention while flying and it seems G5 is off. Simply put on last few cross country IFR flights I would fly radial off VOR and the old GPS would track it showing correct tracking while G5 was off. Same with following localizer during the approach, 3-4 deg difference. Reading the install and Maintenance manual, I see no way of adjusting this. What do you guys think? Is there a way to correct for that and why the difference? Curiously, my EFB (FlyQ) seems to agree with G5!? I really need to look it it again but, as I said panel GPS seems to track Airways with correct Tracking and location on moving map. Another G5 calibration question: It seems manual is calling for Air speed configured (Vne, Vno, Vy etc). but my G5 just does not have that option under configuration page. I downloaded the correct revision of install manual when bought the unit. Is that something that is not on all units? Does anyone have configured ref speeds for your plane on G5? Thank you. Quote Link to comment Share on other sites More sharing options...
hammdo Posted July 5, 2022 Report Share Posted July 5, 2022 I see the same on VOR tracking (off) but not ILS (it’s spot on). Gnc355 and dual G5s.. I'm having a new VOR antenna installed as my signal gets wacky after ~18 miles from the VOR Ill test out next time. -Don Quote Link to comment Share on other sites More sharing options...
201Mooniac Posted July 5, 2022 Report Share Posted July 5, 2022 Igor, not sure what you mean here, do you mean if you fly a GPS track value that matches a VOR radial value it is off? That isn't surprising given magnetic drift. Do you know if you have current IGRF model data in both your G5 and panel mount? 1 Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted July 6, 2022 Report Share Posted July 6, 2022 How does it look on the gps startup test page? Quote Link to comment Share on other sites More sharing options...
jamesm Posted July 6, 2022 Report Share Posted July 6, 2022 I have had a similar issue with G5's and GNC255(Nav/Com) being of 2 to3 degrees off when I do the VOR/VOT check. I thought it was odd. I had the GNC255 CDI indicator many years ago by an avionics shop it was spot on. It never occurred to me that it could be the G5 that is off. Curious to know what version of s/w is ran on the G5's? I haven't updated mine over a year after the GFC500 autopilot install. James '67C Quote Link to comment Share on other sites More sharing options...
Igor_U Posted July 6, 2022 Author Report Share Posted July 6, 2022 14 hours ago, 201Mooniac said: Igor, not sure what you mean here, do you mean if you fly a GPS track value that matches a VOR radial value it is off? That isn't surprising given magnetic drift. Do you know if you have current IGRF model data in both your G5 and panel mount? Adam, Simply put, two GPS tracks are different. And I believe the G5 is off become if I am on airway close to waypoint, my track and bearing to waypoint (VOR) is spot on on panel mount GPS to what I see on moving map. G5 is 4 deg off. Keep in mind, G5 has no GMU11 magnetometer so it's shows magnetic track (no magnetic drift)... Quote Link to comment Share on other sites More sharing options...
Igor_U Posted July 6, 2022 Author Report Share Posted July 6, 2022 To all, G5 was bought less then 18 months ago and had a latest software so we didn't need to do software loading procedure as described per 6.3.5 of Install manual. Software version it came with is 6.82. I got a call form Garmin tech in less then 30' I emailed them and tech suggested to update the software on a new SD card (FAT-32 formatted, whatever that means). He said current version is 8.00. Another thing he mentioned is that G5 has data logging and could be downloaded to the card for them to diagnose it. We'll look at that for sure. The other question was why no reference speeds were configured to G5. Do you guys have that on your unit? Anyone is missing that? We just didn't have that option available (airspeed configuration) when calibrated the G5. According to Garmin tech, this is the feature used on G5 2nd installation (HSI) when the Pin 3 is grounded on the main connector (9 pin). So, it might be so simple that we had Pin 3 grounded and need to remove that. I hope so it's that simple. Looking at the install manual, I see no reason why we would do that so I'm afraid it might be something else. Annual is coming in a month so my IA and I will look into this for sure. Thank you. Quote Link to comment Share on other sites More sharing options...
jamesm Posted July 6, 2022 Report Share Posted July 6, 2022 So I am at S/W version 6.82 as well. If memory serves me correct, you have to enable the data logging for it to work. I know I had to do it on 6.82 s/w version, it is possible that this may have changed in later G5 s/w versions. I suspect that new SD card bought at store depending on the size/capacity could be formatted as NTFS. The (FAT-32 formatted, whatever that means) means that new micro SD card could be formatted as NTFS (Windows NT File System) format as opposed to FAT32 (File Access Table 32 byte) as opposed to FAT16 (File Access Table 16 byte) which real old hardly ever used except maybe in real old DOS computers. There are several other File Systems formats out there. I don't remember what the default Format is for micro SD cards and other SD cards. Garmin probably made mention of it to make sure that is format is correct to ensure proper results. I am surprised that you can't set the 'V'-speeds. all the pin 3 being grounded is doing telling the unit who is primary and who is secondary in a 2 G5 configuration. I had to play with mine to remember how to get to the V-speeds page. off the main page in the configuration mode 'Airspeed'. I had set it long time ago. One thing you could try if you haven't tried already is power on G5 that is configured as the ADI and keep the HSI configured G5 powered off. to see if that would allow you get to the Airspeed menu in the configuration mode. should be off the main menu page in configuration mode. You have to push in on the rotary knob while powering on the G5 unit to get it go into the configuration mode. Hope this helps, James '67C Quote Link to comment Share on other sites More sharing options...
jamesm Posted July 6, 2022 Report Share Posted July 6, 2022 Here is example of what Garmin revision history shows as of today. Quote Link to comment Share on other sites More sharing options...
201Mooniac Posted July 6, 2022 Report Share Posted July 6, 2022 3 hours ago, Igor_U said: Adam, Simply put, two GPS tracks are different. And I believe the G5 is off become if I am on airway close to waypoint, my track and bearing to waypoint (VOR) is spot on on panel mount GPS to what I see on moving map. G5 is 4 deg off. Keep in mind, G5 has no GMU11 magnetometer so it's shows magnetic track (no magnetic drift)... Igor, If I am on an airway (based on centering the VOR) and close to the waypoint, none of my GPSs will agree with the radial so I don't think that determines which GPS is correct and which is not. (The comment about the IGRF model is that if you had an older IGRF model in the panel mount, it might tend to agree with the VOR better as it doesn't account for more recent magnetic drift.) Obviously they are different in your case and that is puzzling, I would definitely go with checkign the data log. You need to make sure that the data logging is enabled in setup and use a micro SD card (less than 8 - 32GB in size). Also, you should have reference speeds configured, it is part of the configuration steps. Good luck. 2 Quote Link to comment Share on other sites More sharing options...
Igor_U Posted July 6, 2022 Author Report Share Posted July 6, 2022 41 minutes ago, jamesm said: I am surprised that you can't set the 'V'-speeds. all the pin 3 being grounded is doing telling the unit who is primary and who is secondary in a 2 G5 configuration. James, I understand the reason of grounding the pin 3 but I was also told that grounding it disables configuration of Airspeed. It's all good if that's the issue (it be easy fix) but I don't remember we done that during the install. Thank you. 1 Quote Link to comment Share on other sites More sharing options...
Stanton R Posted July 6, 2022 Report Share Posted July 6, 2022 Since you are using your transponder as a GPS that doesn't have a database you are more then likely getting true heading instead of magnetic variation corrected heading. Quote Link to comment Share on other sites More sharing options...
Igor_U Posted July 6, 2022 Author Report Share Posted July 6, 2022 2 minutes ago, Stanton R said: Since you are using your transponder as a GPS that doesn't have a database you are more then likely getting true heading instead of magnetic variation corrected heading. Stanton, interesting point. But, IM and Garmin tech confirmed, its a magnetic track. It even say in window I'm not sure how, though. Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted July 7, 2022 Report Share Posted July 7, 2022 Other devices showing true rather than magnetic? Quote Link to comment Share on other sites More sharing options...
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