Ragsf15e Posted May 15, 2023 Report Posted May 15, 2023 So two times now on consecutive flights my GTX345 has popped an error message “No Altitude” or something like that (I need to look up exactly what it said in the manual). Sure enough, atc said they lost my altitude. It’s using my G5s as an encoder and they don’t show any errors or anything weird with the altitude. Both times I turned off the transponder, turned it back on, selected “alt” and it worked perfectly. Both times it was just after takeoff, and the transponder then worked flawlessly for a 3 hour flight. Any thoughts? Anyone know what kind of troubleshooting an avionics shop would want to do if it keeps happening? Heres the error, but I don’t think it lost contact with the g5s as it then worked fine for 3 hours?
47U Posted May 16, 2023 Report Posted May 16, 2023 On 5/14/2023 at 5:20 PM, Ragsf15e said: Any thoughts? Anyone know what kind of troubleshooting an avionics shop would want to do if it keeps happening? How much time has passed since the installation? Before going to the shop, slide the xponder out of the tray and inspect/clean the connectors. Unplug the connector on the G5 and do the same. It’s the intermittent problems that can be the most difficult to fix. Good luck!
Ragsf15e Posted May 16, 2023 Author Report Posted May 16, 2023 2 hours ago, 47U said: How much time has passed since the installation? Before going to the shop, slide the xponder out of the tray and inspect/clean the connectors. Unplug the connector on the G5 and do the same. It’s the intermittent problems that can be the most difficult to fix. Good luck! Yes, I agree. Although I don’t want it broken, it would be a lot easier to fix if it was properly broken! It’s been in there about 6 years. I agree with re-racking it, ill give that a try. I did stick my head under the panel and everything is secure, accessible, and looks like great wiring.
carusoam Posted May 17, 2023 Report Posted May 17, 2023 Does your set up allow you to see what altitude is being reported? My BK transponder 76C? Has a display of pressure altitude on its face… This would help to minimize the possible sources for the error… Starting from the static system, to the device that puts a number on the pressure… to where that number gets reported next… Sometimes the altimeter is involved with reporting the data, since it is connected to the static system… What is the box called that converts the static pressure to altitude code? faded fuzzy memories of gray codes…. Best regards, -a-
Ragsf15e Posted May 17, 2023 Author Report Posted May 17, 2023 1 hour ago, carusoam said: Does your set up allow you to see what altitude is being reported? My BK transponder 76C? Has a display of pressure altitude on its face… This would help to minimize the possible sources for the error… Starting from the static system, to the device that puts a number on the pressure… to where that number gets reported next… Sometimes the altimeter is involved with reporting the data, since it is connected to the static system… What is the box called that converts the static pressure to altitude code? faded fuzzy memories of gray codes…. Best regards, -a- Yes, you can display pressure altitude but that goes blank with the error message. My setup goes directly from the G5 to the transponder via serial cable. No more encoder with grey code! That’s why it’s weird. 1
Ragsf15e Posted August 7, 2023 Author Report Posted August 7, 2023 So this has happened probably 6 times in 40 hours. Never more than once per flight. I wrote Garmin support to ask about it. There’s no Garmin dealer easily available to me. Here’s what I got back. It seems like they have an idea but want to keep a secret? Frustrating. “Drew, Thank you for contacting Garmin International. What dealer are you working with in your area? If you could have them call in and ask for me and I will be able to direct them on a fix for the issue you are having.” What if I was experimental? I didn’t say i was going to fix it myself regardless of rules? Id just like to understand the nature of the issue before I start a wild goose chase with some dealer I have no relationship with? @PT20J have you had better luck? Drew Best Regards,
PT20J Posted August 7, 2023 Report Posted August 7, 2023 4 hours ago, Ragsf15e said: So this has happened probably 6 times in 40 hours. Never more than once per flight. I wrote Garmin support to ask about it. There’s no Garmin dealer easily available to me. Here’s what I got back. It seems like they have an idea but want to keep a secret? Frustrating. “Drew, Thank you for contacting Garmin International. What dealer are you working with in your area? If you could have them call in and ask for me and I will be able to direct them on a fix for the issue you are having.” What if I was experimental? I didn’t say i was going to fix it myself regardless of rules? Id just like to understand the nature of the issue before I start a wild goose chase with some dealer I have no relationship with? @PT20J have you had better luck? Drew Best Regards, My experience with Garmin support is that unless it’s a question that can be answered by reference to the manual they just send you to the dealer. To be fair, it’s hard to troubleshoot remotely especially an intermittent. I doubt it is a connector as Garmin uses high quality connectors unlike older King stuff that used edge connectors. Are the two G5s identical except for one being configured at a HSI and one as a PFD? If so, I would try swapping the G5s to see if it is an intermittent issue with the PFD G5. The G5s do some data logging. I’m not sure what all they capture, but you might put a SD card in and turn on the logging in case it captures something helpful. Skip
Ragsf15e Posted August 7, 2023 Author Report Posted August 7, 2023 1 hour ago, PT20J said: My experience with Garmin support is that unless it’s a question that can be answered by reference to the manual they just send you to the dealer. To be fair, it’s hard to troubleshoot remotely especially an intermittent. I doubt it is a connector as Garmin uses high quality connectors unlike older King stuff that used edge connectors. Are the two G5s identical except for one being configured at a HSI and one as a PFD? If so, I would try swapping the G5s to see if it is an intermittent issue with the PFD G5. The G5s do some data logging. I’m not sure what all they capture, but you might put a SD card in and turn on the logging in case it captures something helpful. Skip I wrote back and got a much more satisfying answer. It seemed that they had some idea of what was causing it by the way tgey answered, and I wanted to know if this was something that could get worse quickly- needs fixed now or could possibly just wait for a convenient time. I fly a reasonable amount of ifr and into/out of class b/c. While not terrible, I’d hope to avoid a problem with my transponder. Anyway, they wrote back that it’s a problem with the gae 12. When I work with a dealer, they’ll send a replacement. Now to find someone to fix it. Western AC at Felts field went out of business.
PT20J Posted August 7, 2023 Report Posted August 7, 2023 1 hour ago, Ragsf15e said: I wrote back and got a much more satisfying answer. It seemed that they had some idea of what was causing it by the way tgey answered, and I wanted to know if this was something that could get worse quickly- needs fixed now or could possibly just wait for a convenient time. I fly a reasonable amount of ifr and into/out of class b/c. While not terrible, I’d hope to avoid a problem with my transponder. Anyway, they wrote back that it’s a problem with the gae 12. When I work with a dealer, they’ll send a replacement. Now to find someone to fix it. Western AC at Felts field went out of business. Crown at KPAE. There is a guy at KTTD. I’m traveling and his card is in my desk at home. Erin at Advanced Aviation would know.
Ragsf15e Posted August 7, 2023 Author Report Posted August 7, 2023 1 hour ago, PT20J said: Crown at KPAE. There is a guy at KTTD. I’m traveling and his card is in my desk at home. Erin at Advanced Aviation would know. Awesome, thanks. I’ll talk to them both. I also like Hillsboro aviation in Hillsboro, but I haven’t had them do avionics yet.
Ragsf15e Posted August 9, 2023 Author Report Posted August 9, 2023 On 8/7/2023 at 2:25 PM, PT20J said: Crown at KPAE. There is a guy at KTTD. I’m traveling and his card is in my desk at home. Erin at Advanced Aviation would know. A little frustrating, but here’s the clarification. They basically want to use a gae12 to bypass the part of their system that doesn’t always work right? Seems strange to me? Unfortunately that entails accessing the back of the transponder, new static line and static checks. “There is an issue specifically with the GAD 29 and GTX interface that can be intermittent in some installations and the installation of the GAE 12 is the corrective action for this. if you have them contact me I will send them a GAE 12 at no cost.”
LardLad Posted February 3 Report Posted February 3 I ended up in this thread with the same intermittent error, on the same 2 G5s and a GTX345 setup in my C. Was the GAE 12 install the end of the problem for you @Ragsf15e?
Ragsf15e Posted February 3 Author Report Posted February 3 1 minute ago, LardLad said: I ended up in this thread with the same intermittent error, on the same 2 G5s and a GTX345 setup in my C. Was the GAE 12 install the end of the problem for you @Ragsf15e? Ha! I never actually did it. It happened so infrequently, was easy to reset and I didn’t have easy access to an avionics shop I trusted so I just kept using it as is. Sorry about that. Did you call Garmin and ask them if that’s still the recommendation? I was hoping they would eventually solve it with a software update.
LardLad Posted February 3 Report Posted February 3 Ahh, ok. I'm inside the mode-c veil so letting it slide probably won't work for me, I imagine I'd get a nasty note or a number to call sooner or later. I've got a few optional items piling up, if I can't get anywhere with connector cleaning I'll probably just have them pull it into the shop at KPAE to take a look. Thanks for the reply anyway, appreciate it! I'll try to remember to post back here whenever I finally get it fixed. 1
Max Clark Posted February 3 Report Posted February 3 On 5/16/2023 at 8:30 AM, 47U said: How much time has passed since the installation? Before going to the shop, slide the xponder out of the tray and inspect/clean the connectors. Unplug the connector on the G5 and do the same. It’s the intermittent problems that can be the most difficult to fix. Good luck! This was where I went. I had intermittent transponder gremlins after the install. In my case a connector wasn't made properly and ground was inconsistent. Replacing the line end to end solved the problem and haven't had an issue since.
TheAv8r Posted February 3 Report Posted February 3 My GTX335 does this very rarely, maybe once every 150 hours. I got to the same state as you Rags, just turn it on and off again and it fixes it and it's so infrequent I don't want to tear the installation apart to fix it. Also have dual G5s in my bird. 1
Ragsf15e Posted February 3 Author Report Posted February 3 The key thing to the “known” intermittent fault is if the gtx345/335 is getting its pressure altitude from the g5s through the gad29. Im not sure if they have the same issue with other sources through a gad29 (like a gi275 or g3x) but apparently the problem disappears if you use an independent altitude source like the gae they wanted to give me. If you already have an independent source, it’s probably something else like @Max Clark mentioned.
rklems Posted February 4 Report Posted February 4 2 hours ago, Ragsf15e said: The key thing to the “known” intermittent fault is if the gtx345/335 is getting its pressure altitude from the g5s through the gad29. Im not sure if they have the same issue with other sources through a gad29 (like a gi275 or g3x) but apparently the problem disappears if you use an independent altitude source like the gae they wanted to give me. If you already have an independent source, it’s probably something else like @Max Clark mentioned. It's interesting that Garmin is mentioning this to folks now, as anytime I've brought up the issue with Garmin, they tell me it's the first they've heard of it, even though I first reported it to them in 2019 and I've talked to other shops who have similar experiences (and I've also talked to other folks who claim to use it all the time without ever having an issue). I've never run in to this issue with anything other than the GAD29 429 airdata interface to GTX335/345 as well as the GNX375. I've had this pop up every time I've attempted to do this interface, even though it is still an approved interface in the install manuals. I stopped even trying to use this interface as the primary, and just always install a GAE12. The last time I tried it was on a GNX375 about a year or two ago, thinking, for sure they had to have resolved this issue by now (Narrator: they did not). At this point I just figure it'll never get fixed and never use it. I've never seen an issue with the airdata feed to GNS/GTN/etc for baro or pressure altitude, seems to only be the transponder products. I even installed a 429 logger on the feed to the transponder when I was first gathering data and the data is still streaming from the GAD29, just seems the transponder stops processing the data for a while, cycling the transponder it goes back to working from the same feed without issue. There never seems to be any definitive trigger for when it stops working, might work fine for 5 flights and then glitch out on one, or it might glitch out several times in one flight. 1
Ragsf15e Posted February 4 Author Report Posted February 4 1 hour ago, rklems said: It's interesting that Garmin is mentioning this to folks now, as anytime I've brought up the issue with Garmin, they tell me it's the first they've heard of it, even though I first reported it to them in 2019 and I've talked to other shops who have similar experiences (and I've also talked to other folks who claim to use it all the time without ever having an issue). I've never run in to this issue with anything other than the GAD29 429 airdata interface to GTX335/345 as well as the GNX375. I've had this pop up every time I've attempted to do this interface, even though it is still an approved interface in the install manuals. I stopped even trying to use this interface as the primary, and just always install a GAE12. The last time I tried it was on a GNX375 about a year or two ago, thinking, for sure they had to have resolved this issue by now (Narrator: they did not). At this point I just figure it'll never get fixed and never use it. I've never seen an issue with the airdata feed to GNS/GTN/etc for baro or pressure altitude, seems to only be the transponder products. I even installed a 429 logger on the feed to the transponder when I was first gathering data and the data is still streaming from the GAD29, just seems the transponder stops processing the data for a while, cycling the transponder it goes back to working from the same feed without issue. There never seems to be any definitive trigger for when it stops working, might work fine for 5 flights and then glitch out on one, or it might glitch out several times in one flight. It took several calls to garmin and some “perseverance” before I got someone who sort of acknowledged that they knew of the issue and would send me a gae for free. However, installing and certifying that would have been on me.
acekng1 Posted February 6 Report Posted February 6 I had the same issue on a GTX 330. I was getting several other intermittent issues on other instruments as well such as my fuel pressure sensor on my JPI 930 occasionally going out. Ended up being a slightly loose field terminal connection at my alternator. They were solved when tightening the connection. All that to say, check all your electrical connections to make sure nothing is loose.
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