GDL-39 & iPad Inflight

Just a quick note on my recent experience with the new GDL-39 and my iPad on my check flight with the new unit.

I installed a GDL-39 to feed ADS-B data to my GDU 37X display. Install went well excluding the lack of updated install drawings. By the way you need to run both Serial IN & OUT from the GDL-39 since you have to set the 37X for Garmin Data Transfer protocol for it to talk and it's a two-way data. Found this data on the updated G3X install documentation.

In the setup you "register" your transponder code so that it will ignore your aircraft as a target. This is a super unit and it works very well and syncs to my iPad with bluetooth.

However, when I went flying on Sunday, I launched the Garmin Pilot application on my iPad to display the GDL-39 data only to receive alerts every few seconds that there was a target very close...only problem it was ME! Showed my N number etc. This continued over and over so I had to close the application.

I called Garmin on Monday and after some research they technician called back to say that while the 37X is configured to ignore my aircraft the iPad software apparently isn't! I'm still confused since the iPad is just a display device but that's the answer. This really makes a very nice application completely worthless during flight. Hopefully, Garmin will fix this issue soon. The Pilot application is really very good and I've moved to it from Foreflight for flight planning.

Regards,

David W. Schaefer
RV6A N142DS

David, when you say "in and out" are you talking the Green Wire and White & Green Wires?

I'm installing one ts weekend and it appears to me the other "Orange Wire and White and Orange Wires" are not used.

Also, how did you get the transponder code to insert into the G3X so it will ignore it?

Thanks,

Installing GDL39 with G3X

SmilingJack said:

David, when you say "in and out" are you talking the Green Wire and White & Green Wires?

I'm installing one ts weekend and it appears to me the other "Orange Wire and White and Orange Wires" are not used.

Also, how did you get the transponder code to insert into the G3X so it will ignore it?

Thanks,

Click to expand...

Hello John,

Page D-12 (Appendix D) of the latest G3X Installation Manual provides wiring and configuration information for installing a GDL39 with a G3X system. You are correct that this installation only requires using the Green and White/Green wires (plus power/ground).

If you are using a Garmin Mode S transponder like the GTX23ES, you will notice that normal setup of the transponder (using the XPDR page in config mode) will insert the Mode S Address for your aircraft on the ADSB config mode page. Nothing for you to do, this is automatic. G3X will then use this mode S address to make sure that your ownship is never misinterpreted as traffic.

Note that if you are using a panel mount Mode S transponder like a GTX330 or GTX330ES and do not have it selected on the XPDR config page, the Mode S Address field on the ADS-B config page can be manually edited to enter your Mode S address. The FAA registration inquiry page shows the Mode S address for your aircraft in both octal and hex formats, both of which are supported on the G3X ADS-B config page.

Additionally, G3X systems automatically do something else really useful when using a GDL39. The GDL39 has an internal sensor to measure pressure altitude, but when used with a G3X system, the high accuracy pressure altitude measured by the G3X ADAHRS is passed over the datalink to the GDL39 so it will use the G3X pressure altitude instead of the pressure altitude measured by its internal sensor.

The single pressure altitude measured by the G3X ADAHRS is used for PFD altitude, transponder pressure altitude, and GDL39 traffic relative altitude determinations. Everything is highly integrated and in sync for this critical piece of information.

Let us know if you have any additional installation questions, but installing a GDL39 on a G3X system is very simple with just a single RS-232 interface.

Thanks,
Steve

Yes you use the green and white/green (S1) back to your unit. I used S2 on the 375 since S1 is used for GPS map data from the 430. Once set up you'll get the ADSB setup screen where you can enter your transponder info.

Unfortunately none of this fixes the issue with the iPad / bluetooth display issue. The Garmin Pilot application is completely worthless in flight since it alerts every few seconds to the "danger" of your own aircraft! Something tells me there was a lack of planning somewhere or a rush to get the software out.

Enjoy the 39 .. it works great.

Regards,

DWS
RV-6A N142DS
www.n142ds.com

Just one more data-point for your troubleshooting, but I've been flying the GDL-39 and an iPad with Garmin Pilot since just after Oshkosh and have never experienced this problem. It works fine for me in both of the airplanes I fly, one of which has a GTX 330ES in it.

A fellow club member has the Android version and we have flown together with an iPad and a Nexus 7 both running G-Pilot and paired to the GDL 39 in our ES-equipped plane and have not seen this issue. Wow...that sounds a lot nerdy-er than it seemed at the time.