On Wednesday, November 27, 2019 at 10:59:06 PM UTC-8, Charles Longley wrote:
I am not 100% sure a squat switch is needed in a glider. Here’s a quote from Garmin through an AOPA article-
For aircraft without retractable gear aircraft, Garmin ADS-B equipment analyzes various data available to the system for air/ground determination. This includes groundspeed; vertical rate; airspeed; radar altimeter, if available; a rotorcraft’s collective position, if available; comparison of aircraft altitude to nearby airport elevation, if available; and comparison of groundspeed and/or airspeed to aircraft stall speed, Garmin’s Stone said.

Trig is the preferred transponder for gliders due to size. Does anyone know if a Trig transponder analyzes data like Garmin equipment?

Uh yes, that's the "GPS" setting under "Select Squat Switch type".

You keep making statements about stuff or asking questions about about things that is already well settled and has been mentioned here many times.

This is years old information. I identified this GPS groundspeed determination in Trig Transponders as a problem in early glider installs. I let Trig know about that. I've described it all over r.a.s. I mentioned at it at an SSA convention talk. I've worked with every Trig glider dealer in the USA to let them know about it and to get squat pitot switches available. And when Trig updated the GPS algorithm recently I checked with them and they continued to state that this GPS based algorithm was *not* intended for use in glides or other aircraft that could have vey low (or negative) ground speed.. And I posted that on r.a.s. as well.

The very worse thing you can do for a glider that will fly in wave is to use GPS based determination.. It very likely will fail. For 2020 Compliance if 91.227 did not imply that automatic switching was required people would likely be better off with manual switching. For TABS installs just leave it manual. I don't know how many times I have posted this on r.a.s.

Garmin GPS based algorithm will likely fail in similar situations, you can ask Garmin what they are.