G1000 Transponder Failure

[Jeff_S]

Hey all. I went out this morning for some air work and never made it off the ground because I was getting a XPDR FAIL alert and the red X in the transponder box on the PFD. I tried all the standard troubleshooting stuff, pulled the circuit breaker, etc. Even talked to Garmin's AOG service and they said it would require a technician to look at. Anybody ever had a similar issue with a G1000 transponder? I'm looking for troubleshooting ideas. Thanks!

[Robert C.]

hmm...nope, haven't had that. Every few weeks or so the HDG on the HSI won't come up and then recycling the power on the G1000 works to make it initialize just fine.

Sorry I can't be more helpful.

Robert

[ArtVandelay]

Is the transponder a different box?

Assuming it is and you can get to it, I would pull the wiring harness, spray connectors with some electronic cleaner, plug it back in. Also if you can access the circuit breaker, check it with a ohmmeter to make sure you have a good connection.

[markfoster7700]

Try sliding the LRU out and sliding it back in. You can even spray some contact cleaner on the connections if you want. This action has been the cure for every red X that I have ever had. It is now just routine maintenance for me, about once every 6 months seems to do the job. 

[ArtVandelay]

Try sliding the LRU out and sliding it back in. You can even spray some contact cleaner on the connections if you want. This action has been the cure for every red X that I have ever had. It is now just routine maintenance for me, about once every 6 months seems to do the job. 

Great minds think a like

[Jeff_S]

Hi Mark. Is the transponder LRU clearly marked? I assume it's in the avionics bay in the back, right, and not behind the GDUs? I thought of trying this while I was at the plane but didn't want it to make things worse by getting it wrong.

[markfoster7700]

Jeff,

You will never hurt anything by sliding every LRU you have out and back in.  I don't know what serial number you have, so I don't know for sure if your transponder is clearly marked or not.  I did have one "red X" failure that was the main connector on the G1000 interface (not an LRU, but in the same bay in the back), and the solution to that was to spray contact cleaner on the connectors and place a zip-tie around the unit to ensure that the connector could not back off of its connection.

In general, there is really no harm, and mostly only good, from disconnecting and reconnecting electrical connections.

Mark

[Yetti]

This was the same thing you used to do to fix IBM Mainframes.   The tech would come in and reseat all the cards.  Usually fixed it.   In a less gracious manner I put myself through college doing two way radio work during the summer.    For some radios that were in mixer trucks they would get coated with cement dust and it was a high humidity environment (inside the cab, no air conditioning).  The edge connectors would lose contact.   A wack with a hard hat would reestablish the board edge connectors.    Re seating cards is pretty much SOP for lots of things.

[LANCECASPER]

I think the transponder in the G1000 is a GTX33 if you're getting Mode S traffic. If there is something wrong with it and it has to go back to Garmin, it might be a good time to upgrade to a GTX33ES (Extended Squitter).

[Jeff_S]

Well, I will take a crack at reseating the cards to see if that helps. Yes, I have the GTX33 at the moment.  If there is something wrong with the transponder card, I'll see about upgrading to the ES, although since I am currently non-WAAS this won't have much benefit. It may not even work yet in my installation. Hopefully it won't come close to any of that.

[Jeff_S]

Just to close the loop on this, it turns out there is a known, but very rare, glitch in the software that can cause the transponder to lose its configuration. It's a simple step to reload the config settings but it has to be done by a Garmin service center (or at least someone who knows how to config the software properly). There was nothing wrong with the connections or anything like that. So it was an easy fix and not too expensive...and the likelihood of it happening again is just as rare.  Oh well, one more thing to watch out for. But now I've developed my flight strategies if it happens again...I've got the PDK Tower and Atlanta TRACON phone numbers in my contacts list so I can call them quickly if I need a no-transponder clearance!