GTX345 Mode C dropped out twice

[Ragsf15e]

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]

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]

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]

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]

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.

[Ragsf15e]

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]

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]

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]

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]

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]

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.”