Pitot/static leak issues when using a "squat switch"

Great idea, Mark!Â* But you'll have to figure out how to connect them
electrically to the transponder.Â* I don't think the FAA will be able to
hear the scraping given the distance to most glider fields.Â* Then again,
those would make a great gear warning system!

BTW, I would have expected to find those in the JC Whitney catalog...

On 11/30/2019 8:45 AM, wrote:
https://www.amazon.com/United-Pacifi...xpY2s9dHJ1ZQ==
https://www.amazon.com/United-Pacifi...s9dHJ1ZQ==,,-- ,Dan, 5J


https://www.amazon.com/United-Pacifi...s9dHJ1ZQ==,,--
,Dan, 5J
--
Dan, 5J
https://www.amazon.com/United-Pacifi...s9dHJ1ZQ==,,--
,Dan, 5J

On Saturday, November 30, 2019 at 10:45:49 AM UTC-5, wrote:
https://www.amazon.com/United-Pacifi...xpY2s9dHJ1ZQ==

Best idea yet!!

Actually out of curiosity I looked at the pin out diagram for a Garmin transponder. There’s no pin out for a squat switch. Guess they do air-ground logic through programming as quoted by AOPA. Too bad they don’t make a smaller transponder.

I'm pretty sure the Trig transponder allows the GND/ALT determination to
be made without use of a squat switch.

On 11/30/2019 1:21 PM, Charles Longley wrote:
Actually out of curiosity I looked at the pin out diagram for a Garmin transponder. There’s no pin out for a squat switch. Guess they do air-ground logic through programming as quoted by AOPA. Too bad they don’t make a smaller transponder.

--
Dan, 5J

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.

You can also get Fuzzy Dice and a Bobblehead Jesus to replace the slip/skid ball and G-meter. Just sayin'

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

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

On Saturday, November 30, 2019 at 8:26:42 AM UTC-6, Eric Greenwell wrote:
Darryl Ramm wrote on 11/29/2019 10:36 PM:
Again if you are installing TABS just set the transponder squat switch to "None" and use manual ON/ALT switching on the transponder.

I might forget to switch it correctly. Would using the "gear is down" switch to
change between ground/airborne be a sensible choice? The pattern (and the first
500'-1000' after the takeoff) would be flown showing the glider was on the ground,
of course, but that might be better than having the whole flight showing as on the
ground.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

If you use a squat switch with a Trig transponder, I believe that also puts the Transponder into GRND mode, so it wouldn't be responding to interrogations. The one place you do want ADS-B OUT and your transponder operating is in the pattern. That's where half of the midairs occur. Turning off ADS-S B OUT or your transponder as soon as you lower the gear is a really bad idea.

On Saturday, November 30, 2019 at 7:30:25 PM UTC-8, Mike Schumann wrote:
On Saturday, November 30, 2019 at 8:26:42 AM UTC-6, Eric Greenwell wrote:
Darryl Ramm wrote on 11/29/2019 10:36 PM:
Again if you are installing TABS just set the transponder squat switch to "None" and use manual ON/ALT switching on the transponder.

I might forget to switch it correctly. Would using the "gear is down" switch to
change between ground/airborne be a sensible choice? The pattern (and the first
500'-1000' after the takeoff) would be flown showing the glider was on the ground,
of course, but that might be better than having the whole flight showing as on the
ground.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

If you use a squat switch with a Trig transponder, I believe that also puts the Transponder into GRND mode, so it wouldn't be responding to interrogations. The one place you do want ADS-B OUT and your transponder operating is in the pattern. That's where half of the midairs occur. Turning off ADS-S B OUT or your transponder as soon as you lower the gear is a really bad idea.

Mike has an important point. Please do not dick around and end up disabling a safety system. If you are in the air the transponder needs to be in ALT mode.

What is actually going on is a bit more messy, but "not responding to interrogations" is a useful summary. In GND mode Mode-S transponders will actually reply to direct addressed Mode-S interrogations, and do some other things, but that a far from a necessary set for the transponder to operate normally (e.g. it can't be acquired as a target by SSR). It will keep transmitting ADS-B Out, but messages encode the glider is on the ground, and some message content changes slightly. How all different ADS-B receivers all respond to that is uh anybody's guess. I just have an image in my mind of somebody seeing a transponder reply LCD thingy blink when in GND mode at some time and say "ha see it's replying OK". Ah nope, it's replying to a small subset of stuff. Flying in GND mode is a bad idea.