WAAS upgrade woes

[mhoran]

I don't disagree with you though, RFI seems the most plausible explanation. I don't understand how the transponder could have otherwise just gone bad as a result of the WAAS upgrade. It's unfortunate that there's no way to monitor the GTX-345 GPS status without hooking up a laptop with special software.

Lancaster hasn't been able to reproduce the traffic fail issue that brought me there in the first place; though they did fix the mode C issue that brought this all to my attention, which was ultimately due to RFI. Those RFI issues were COM/ELT related.

Since replacing a seemingly bad GIA my G1000 GPS hasn't dropped out like it was doing before. But this doesn't seem to be an instance of GPS antenna interference either -- only *one* GPS receiver was dropping out. But since I can't see the status of the GTX-345, I have no idea what's going on there.

[CFIDave]

Unfortunately the fleet of Legacy G1000 DA40s (Lycoming DA40s in North America like yours) is stuck in a bad place: They're still running 2012-era G1000 software that's only GDU Version 12 -- which was written *before* the GTX345R ADS-B IN/OUT transponder was developed and introduced years later. This has a number of implications:

- With old GDU Version 12 G1000 software, the GTX345R can't use WAAS GIA63Ws as a GPS position source -- so owners have had to purchase and install a more-expensive version of the GTX345R with its own built-in WAAS GPS position source, and install a 3rd GPS antenna. This has led to multiple "ADS-B Fail" annunciations and RF troubleshooting issues (as you've noticed).

- Because the old 2012-era GDU V12 G1000 software pre-dated introduction of the GTX345R (or the ADS-B OUT-only GTX33ES transponder), there's no way for techs using Garmin's G1000 Installer software to configure that transponder option during G1000 installation. GTX345R transponder installation simply isn't integrated with the G1000 as with later G1000 software. Instead, techs have to separately connect a laptop to the GTX345R (via a USB cable and additional software) to configure just the transponder.

- For the G1000 to display ADS-B IN traffic and weather running old GDU V12 software, the GTX345R has to emulate ancient deprecated GDL90 (a pre-standard, non-ADS-B-compliant GPS IN/OUT transceiver used for early ADS-B trials) protocols to the G1000.

The solution to all of this is for Diamond/Garmin to certify slightly newer (2015-era) GDU Version 15 software for DA40s with Legacy G1000s. GDU Version 15 software is already available for WAAS DA42s and DA62s with Legacy G1000. Diamond is supposedly working on certifying GDU 15 software for DA40s, and originally said they'd make it available later this year, but it remains to be seen if this will happen.

[mhoran]

Another trip to and from Lancaster Avionics and my issues persist. The shop discovered a new service bulletin that seemed like it could be related: https://support.garmin.com/en-US/aviati ... foA4XUo6pA. The SB supposedly resolves issues with internal GPS. While my flight home was uneventful as was another flight over the weekend, I went out again tonight to fly in the pattern where I can generally reproduce the issue. As I was turning base on my second lap of the pattern, I got a momentary ADS-B fail and traffic fail alert. They immediately cleared themselves, but they alerted nonetheless.

After landing I was hopeful that this was just the SB working as expected. But I pulled an ADS-B performance report and it indicated that Flight ID and Emit Cat elements were missing. I don't even know what could be going on at this point since those parameters are programmed directly into the GTX-345. I'm getting pretty tired of this.

[Charles K]

That is why I replaced my top Com with a Comant Com/WAAS Combo.

BTW, this issue would go away completely if Diamond would finally come out with its promised G1000 GDU Version 15 software for the Legacy G1000. The GDU V15 software enables the GTX345R to obtain its GPS location from the GIAs (just like NXi), rather than requiring use of a GTX345 internal GPS with a 3rd GPS antenna.

[mhoran]

That is why I replaced my top Com with a Comant Com/WAAS Combo.

I'm also having continued RFI induced drop out for both my GIAs (but NOT for the transponder) so I can't imagine the combo COM antenna would do me any good. I have the WAAS / XM combo antenna, which was working fine until my WAAS upgrade.

Fortunately the RFI drop outs are minimal and Lancaster informed me that the GIA does some magic notch filtering of its own in software (I also have hardware notch filters that were installed along with the ELT they replaced.) But when I transmit anywhere around 121.5 I do get resonance on 121.5, which is quite odd. I figure that is also causing the GPS interference, but I believe the transponder issues are unrelated at this point because we verified with the laptop setup that the transponder is not losing GPS fix, at least on the ground.

[Charles K]

Was supposed to be available last October per their original SW upgrade announcement. Do any of the Diamond 6 have any news from Diamond?

Been waiting for this upgrade patiently

The solution to all of this is for Diamond/Garmin to certify slightly newer (2015-era) GDU Version 15 software for DA40s with Legacy G1000s. GDU Version 15 software is already available for WAAS DA42s and DA62s with Legacy G1000. Diamond is supposedly working on certifying GDU 15 software for DA40s, and originally said they'd make it available later this year, but it remains to be seen if this will happen.

[Charles K]

When my upgrade was done by Absolute Aero in KHWD they replaced both GPS antennas and used all new cabling as specified in the upgrade. Also the entire Ethernet cabling assembly that runs from the cockpit to the rack was replaced, again as specified in the upgrade work instructions. The 1K labor sounds very inexpensive leading me to believe that perhaps you did not get all necessary wiring replaced?

I have the combo Comant and 345R with the built in GPS. I have had no RFI issues that I am aware of.

[Charles K]

I stand corrected - I reread the drawings in the link and you are right. It does not say it needs the new cables.

I might be wrong here - but these drawings are general for the new plane build and not specific to the upgrade. I'll have to dig up the paperwork I have but I believe new antenna cables and ethernet wiring are a part of the install kit.

Cannot find anything specific on paperwork but it is possible that the coax required for the WAAS is different than for non WAAS. All I know is that I have new antenna cables and a new ethernet wiring assembly that included an all new lightning protection resistor board as well. Have had no RFI issues.

I know they replaced the antennas. I don't think they replaced the cabling. Reading the -1 MDL drawings for the STC, replacing the cabling is not required: https://static.garmin.com/pumac/G1000:D ... 0,WAAS.pdf.

[Boatguy]

I went out again tonight to fly in the pattern where I can generally reproduce the issue. As I was turning base on my second lap of the pattern, I got a momentary ADS-B fail and traffic fail alert. They immediately cleared themselves, but they alerted nonetheless.

The ability to reproduce the error at a specific location seems interesting. Is there something at the airport that could be causing the interference? VOR, ILS, DME or ??

[Boatguy]

Was supposed to be available last October per their original SW upgrade announcement. Do any of the Diamond 6 have any news from Diamond?

Been waiting for this upgrade patiently

The solution to all of this is for Diamond/Garmin to certify slightly newer (2015-era) GDU Version 15 software for DA40s with Legacy G1000s. GDU Version 15 software is already available for WAAS DA42s and DA62s with Legacy G1000. Diamond is supposedly working on certifying GDU 15 software for DA40s, and originally said they'd make it available later this year, but it remains to be seen if this will happen.

We are patiently waiting for the next meeting to be scheduled by Diamond.