GTX 345 Failure

Discussion in 'Avionics and Upgrades' started by Arrow115, Mar 16, 2020.

  1. Arrow115

    Arrow115 Pre-takeoff checklist

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    Has anyone ever had any issues with random inflight failures of their GTX 345? This has been going on for the past few months. It does appear random as we wont have any issues for a while and then it happens again. I attached a picture of the initial message. The only way to get it working is to power cycle the transponder. Pressing ALT or anything else doesn't help. It does show a message on the messages page that says "1090ES ADS-B OUT FAILED"
     

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  2. bnt83

    bnt83 Final Approach PoA Supporter

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    I see it every-time there is no GPS lock on my GTN, (takes about a minute or two of no GPS lock to post the message) like turning it on in the hangar.

    Is your GTX using an internal GPS receiver or one that is panel mounted like a GNS/GTN etc?

    I may have seen it happen in flight maybe once or twice in 3 years.
     
    Last edited: Mar 16, 2020
  3. Arrow115

    Arrow115 Pre-takeoff checklist

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    My GTX is connected to my GTN 650. When this happens, its always inflight and the 650 appears to work as normal.
     
  4. NordicDave

    NordicDave Cleared for Takeoff

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    I’ve a GTX-345 with a Garmin GNU-430W as position source for almost 4 years, and have not seen any error. It’s been very reliable. What does Garmin say? Have you called them or checked with a good Av shop? Curious if this is related to the unit or the installation.
     
  5. bnt83

    bnt83 Final Approach PoA Supporter

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    Probably should have the softwares updated if applicable.
     
  6. Chip Sylverne

    Chip Sylverne En-Route

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    Fear is the poison of our lives.
    Any GPS testing areas nearby? Have you changed cell phones, or started carrying a SPOT locator recently? Which port on the 345 is receiving the position data? It could be a bad crimp in the connector on either the GPS or xponder end.
     
  7. MBDiagMan

    MBDiagMan En-Route

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    I would fully expect that there is a flaky connection somewhere.
     
  8. Arrow115

    Arrow115 Pre-takeoff checklist

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    I am on the list for my avionics guy. He mentioned a possible bad connection as well. We shall see. I am going to get the firmware version numbers of the transponder and 650 to see if there are any updates that are available as well. Thanks for all the suggestions.
     
  9. Chip Sylverne

    Chip Sylverne En-Route

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    Does anyone know if there is some way to confirm that valid position data is being sent from the GPS and received by the xponder? For instance, the GMX and MX 20 have a flag that generates if the transponder isn't receiving valid data. There is also a system page you can look at. Does the 345 have some way of confirming valid pvt data is being received, other than a 1090es TX out fail message? That could be a n antenna or other fault, not necessarily bad data.
     
  10. bnt83

    bnt83 Final Approach PoA Supporter

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  11. Chip Sylverne

    Chip Sylverne En-Route

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    Thanks, but I still see no way to see some sort of valid data message. Looks like check source satellite lock, ring wiring, check configs. I suppose you could put a scope on the TX pin of the source and look for square waves. But no way for the gtx to confirm valid data.
     
  12. bnt83

    bnt83 Final Approach PoA Supporter

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    I believe there is a diagnostics menu similar to GTN were you can watch the code being received on input ports live.

    The fail messages are strange for sure, especially when they light up like a Christmas tree when turned on indoors. There isn't a damn thing wrong with it but you wouldn't know that.

    The internal GPS versions must have GPS antenna connected and the keep alive wire hot to keep the thing from flashing "service soon", even if you aren't using that GPS receiver. (note: If you aren't using the internal GPS the keep-alive wire only needs to be hot when the transponder is on)
     
    Last edited: Mar 17, 2020
  13. GBSoren

    GBSoren Pre-takeoff checklist

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    My altitude encoder went tango uniform, I don't remember if I got an error message or not. I did get a letter from the FAA letting me know that my ABS-B had failed.....this was a couple years ago.
     
  14. Chip Sylverne

    Chip Sylverne En-Route

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    Well, we got it hammered out. The correct configs from an IFD to a gtx345 using the IFD as the ADS-B position sensor are IFD rs232 out ADSB+ (G2) to GTX rs232 in ADSB FMT 2. As a little e experiment, we tried GTX legacy 422 with a GMX 200. No go.
     
  15. nrimmer

    nrimmer Filing Flight Plan

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    I will try this. I randomly get a similar message - just the "no 1090ES" part not the "failure" part. Posted about it a while back and never came up with a solution. Checked all the connections, but didn't think about adjusting configuration.