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ADS-B Performance Report Failure

Michael Burbidge

Well Known Member
I had a Garmin GDL-82 installed in my RV-9A in January. On the first couple of flights I pulled an ADS-B Performance Report and everything looked good.

This week I tried to pull a report on my latest flight just to check in on things. I got an email back saying the report could not be generated, so I pulled a flight from a few weeks ago with the same result, the report could not be generated.

So I went on FlightAware and found both flights. FlightAware is able to pull ADS-B information on the flights. But in looking closer at the two flights, I noticed that 18 minutes into both flights there was a significant gap in ADS-B data.

https://flightaware.com/live/flight/N459PM/history/20200414/0026Z/KPAE/KPAE
https://flightaware.com/live/flight/N459PM/history/20200421/0018Z/KPAE/KPAE

The install is with a Garmin GTX327 transponder.
I have DeltaPop Blade Transponder antenna.

Not sure where to start looking. It would be so much easier if it just didn't work at all.

Any ideas?

I had a repair shop do the install. I've done 5 flights since the install. Do you think it is reasonable to expect them to find and fix the problem?

Has anyone had similar problems with same equipment?

Thanks,
Michael-
 
In both examples, your dropped portion of the flight appears to be where the ADS-B ground stations, GBTs, were to the right side of the airplane. Possibly antenna blanking/ blocking? As a next step,
I would get a Stratus portable receiver with foreflight, and fly while monitoring "ownship" performance realtime.
If it really is failing, it could be the transponder needs a tune up.
 
Ownship

with the Stratus connected to Foreflight, on the map page, select settings dropdown (gear symbol). scroll all the way to the bottom of that menu, and you will see Stratus, and it should show "connected". Tap on that, and you will get the Stratus menu. About halfway down, you should see "ownship" Tap on that, and you will see a bunch of data on the ADS-B out performance. As you scroll, you should see all of the parameters color coded in green. Anything out of tolerance will show up in red.
 
In both examples, your dropped portion of the flight appears to be where the ADS-B ground stations, GBTs, were to the right side of the airplane. Possibly antenna blanking/ blocking?
Unless you were doing some serious maneuvering I highly doubt it. These are not laser beam transmissions.

If it really is failing, it could be the transponder needs a tune up.
THIS is much more possible, or maybe the transponder is intermittent/failing?

:cool:
 
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Flight following

I suppose if I went on a flight with flight following, they would notice if my transponder dropped off.

Michael-
 
Latest software?

Not familiar with your Garmin transponder but I do know that I had to send my Trig TT31 transponder in for a software update in order for ADSB to work properly. I would check your software version (should be displayed on boot up), then check to see what Garmin?s latest version is.
 
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