A Simple Plan (or so we thought)...ADSB Upgrade - Garmin

I have an RV9A with a Garmin GNS430 WAAS GPS and a GTX 330 transponder. The plan being executed with my avionics dealer was to have my GTX 330 sent to Garmin for the ES upgrade (done) and then the avionics dealer would send the upgraded transponder back to me, I would re-install it in my plane, and the guidance was that the transponder would again operate in mode-C until I could get the plane into the avionics shop where they would perform the final steps of building the harness to connect the GTX transponder to the GNS430 GPS, install said harness, test, do the paperwork, and I would be ADSB Out compliant.

Well, today I slid my GTX 330 back into its rack and went for a flight. I was a little skeptical that the transponder would operate in Mode C again, and, unfortunately, I was right. (The older I get, the more skeptical I am and unfortunately, the skepticism is usually right.) No mode C reporting. The local approach control said they were getting my squawk code, but, no mode C altitude. I tried pushing all sorts of buttons on the GTX transponder, including turning altitude reporting on, but, no luck.

It is the weekend of course, so, Garmin and my avionics guy are closed.
Any thoughts on what needs to be done to get my transponder mode C operational?

Thanks,


Curt

Do you have the 430W and GTX330 install manuals? If so, you have what you need to make the boxes work and be 2020 ADS-B out compliant.

Carl

Carl - Yes...Thanks, but, only looking to operate in Mode C at this time.

Carl:

Yes...I have the manuals, but, it is my understanding that a cable needs to be run from the GNS430W to the GTX330 so that the GTX330 has the location information it needs for ADSB Out. Until I can get to the avionics shop to the two units connected, I just want to get back to operating in Mode C with my upgraded transponder. I know that GTX330's, even upgraded for ES, and operate Mode C. I just don't know how to make mine do so at this time. Garmin changed something when they did the upgrade, or else it would still be operating Mode C.

Thanks,

Curt

Curious. You took a Mode S transponder out, sent it in for the ES upgrade, and putting it back it no longer does Mode S, let alone Mode C.

I hope it's an easy Monday config change, since this is very close to my current thinking on 2020 compliance

Yes - That is What I Did

Rob...That is exactly what I did...I hope this is a simple config change also...again, the avionics person that I'm working with thought the upgrade would have no impact on me operating Mode C or S until we changed over to ADSB Out.

What are you using for an encoder? The settings were probably reset back to factory defaults. Give me a call & I may be able to help.

You don't need an avionics shop to add the "cable" to the harness. It's 1 wire. Easy peasy. It's a little bit if a pain to get into the connectors, but an hour or two of your time & you're done. Hop down to my shop this week & I'll supply pins, wire & instructions & you can do it yourself.

I agree with Jesse - just did this myself a couple of months ago, upgrading the 330 to an ES in our RV-3 by sending it back to Garmin., It came back with all of the serial data settings wiped out - so you need to set those up to get it recieving the altitude again. The books tell you how to do it if you are used to decoding them. If not....Jesse offered to talk you through it!

Paul

Jesse Saint Was Correct - Problem Solved - Thanks!

Jesse:

I followed your instructions on setting up the transponder to receive input from the EFIS and the GPS. Took a test flight and the approach controller confirmed all is working properly. Garmin did set everything to the default settings when they did the upgrade. Thanks again.

Regards,

Curt

Just being my very small part of the VAF brain trust. Glad I could help.

Phew... glad that worked out!

Back to my 330ES shopping.