On Saturday, November 30, 2019 at 6:47:48 PM UTC-6, Dan Marotta wrote:
It's been a while, but I believe Trig uses GPS ground speed to determine
flight status.Â* The concern is about gliders flying in wave and clocking
extremely low ground speed resulting in the transponder reporting the
glider on the ground.

On 11/30/2019 5:37 PM, Mike N. wrote:
How is Trig determining ground / alt without a switch?

I'm planning on a manual switch. I'll just add setting it to alt in my pre-takeoff instrument set scan.

--
Dan, 5J

the trig electrically allows gnd/alt determination several ways, not all are approved.
1. no determination
2. gps determination (problematic in wave for gliders)
3. manual switch using the "squat switch input"
4. pitot pressure squat switch from peregrine.
there may be other schemes, but these are some.

Scott