Garmin GPS 20A with Trig TT22 in Experimental Glider - OK?

On Thursday, December 17, 2015 at 9:49:30 PM UTC-8, Mike Schumann wrote:

Gliders are currently exempt from the 2020 ADS-B rules. As a result, you should be able to use a non-compliant GPS source with a Trig21 or Trig22, as long as the Trig is compatible with the GPS's datastream. Even though the GPS source is non-compliant, it will trigger the ADS-B ground stations so that you will get TIS-B and ADS-R transmissions.

To be clear here if your glider is certified you cannot install any old GPS source. You needs to meet the FAA requirements which includes a TSO'ed IFR GPS source, discuss with your A&P/FSDO.

Unless you are a super-geek wanting to play with this stuff, just wait and see what happens with ADS-B and TABS carriage requirements for gliders.

The FAA is making it clear that non-compliant ADS-B out sources will not continue to receive ADS-B ground services in the future even if they do now. January 2016 I think is the cutoff threatened/promised by the FAA, if SIL/SDA=0 from your GPS source you will not be provided ADS-R and TIS-B ground services. And in the meantime the friendly FAA may drop you a snail mail to remind you that your aircraft is flying around with a non-complaint ADS-B Out. Having an ADS-B Out system that triggers ADS-B ground based services (ADS-R and TIS-B) won't help you anyhow if your ADS-B receiver is a PowerFLARM which receives 1090ES direct and is not capable of receiving ADS-R or TIS-B data).


This is what the Dynon Skyview systems do today. According to Dynon, this will continue to work after 2020 if you are flying in airspace where ADS-B is not required.

I expect that we will see affordable 2020 compliant GPS sources in the relatively near future. The Dynon units, which are suppose to start shipping by the end of this year, have set a pretty aggressive price point (under $600). While the Dynon module only works with the Skyview system, I was talking to an engineer at Trig a couple of months ago, who told me that they were planning to introduce an affordable compliant GPS source at a similar price point shortly after the Dynon units start shipping.

One thing that you should think about if you want to be fully 2020 compliant is that you buy a Trig21, NOT a Trig22 transponder. The Trig22, while it is ADS-B OUT compatible and will trigger the ADS-B ground stations, is NOT 2020 compliant.

Good advice, if buying a transponder now and wanting best ADS-B options/flexibility in future. But in the big picture again this may change if TABS carriage regulations happen (the TT-21 meets TABS power requirements even if it does not meet ADS-B out power requirements).