On Monday, January 6, 2020 at 9:38:47 PM UTC-8, Eric Bick (DY) wrote:
TRIG shows a new product on their website - TN72 X GPS Receiver (which couples with a cheaper GPS antenna than the TA70 WAAS antenna). They now show 2 TN72 versions - one with label TABS (SIL=1) and one with label X (SIL=3) on the face of the box. The TABS can be installed on experimental or certified gliders giving ADS-B, but not 2020 compliant (which is what TABS was intended for originally). They say the X version, set at SIL=3, for LSA, homebuilt, and experimental gliders, has been flown in rule airspace and meets full 2020 compliance, per the FAA automated test flight software. The specs for the TABS and X versions in their brochure are identical (and TRIG says they are identical) - the only difference is one is set to TABS (SIL=1) and the other, X version, set to SIL=3, which means 2020 compliance for ruled airspace. Anyone know what is going on? And, more importantly, are they moving toward demonstrating a more cost effective solution to 2020 compliant ADS-B for certified gliders (as well as experimental), enabling them to use the TN72 and X with standard GPS antenna at about 1/4 the cost of the TN70 GPS receiver and TA70 WAAS antenna?

I've covered this all before on r.a.s. There is nothing new, this is all old news, the "different models" TN72 were launched around one to two years ago. Trig make great products but unfortunately have tripped up here on basic marketing, and are just confusing customers... all in an effort that was intended to make things clearer. Not sure how that was ever supposed to work. I suggested they not use this confusing naming, but they did. Nothing has changed recently with GPS antennas either, the TA50 has been available for a long time.

The TN72 GPS never unchanged, it's the same box it has always been. Wether an installer can claim it is SIL=3 or SIL=1 depends on whether the install is in an experimental aircraft (you can claim SIL=3/2020 compliant) possible) or a type certified (you can't claim SIL=3 so do SIL=1/TABS).

No difference in these TN72 GPS device models at all. It's just what you tell the transponder is attached. ... and uh no don't try to cheat and set SIL=3 in a type certified aircraft... you are flying around broadcasting the SIL=3 flag, and the FAA has a database of type certified aircraft that have "real" ADS-B out installs from A&P IA submitting Form 337s for ADS-B out installs in type certified aircraft... and yours won't be there. Are you athletic enough to squeeze out of the bathroom window while the feds are knocking on your front door? :-) I'm not. All pretty frustrating , specially for gliders, but hey I did not invent the regulations.

What *exactly* would it take under current regulations and FAA policy to be able to use a low-cost (say non-TSO-C145c) GPS to do full 91.227/2020 Complaint ADS-B Out in a type certified aircraft? I don't know. But the core step there would be to develop an installation STC. And that's likely to need a lot more work than with a already approved say TSO-C145c GPS, and I suspect that is not economically justifiable given a likely small total increase in market made possible. That the TN72 is separately TSO-C199 approved has no bearing at all on 91.227/2002 compliance. It might as well be TSO-ed as an aviation cigarette lighter adapter (TSO-C71 for those playing along at home).