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

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?

To answer the original poster. When something is changed or added to a pitot/static system the A&P or Repairman is required to do a leak check.

Ha answered my own question through a little research! Trig recommends an airspeed switch- https://www.trig-avionics.com/librar...ust%202018.pdf
I’ll have to give it some thought before I install one.

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.

So you’re the RAS police Darryl?

On Thursday, November 28, 2019 at 10:42:19 AM UTC-8, Charles Longley wrote:
So you’re the RAS police Darryl?

No, but when people keep posting confused/wrong stuff here, especially where it has the ability to affect safety, I will keep correcting them. Sadly I did not see your update before you posted, or I would not have said anything. Since you are an A&P IA I expect people in this community to believe you will get stuff right. And unfortunately amongst the useful stuff you post there are some posts from you about UAT Out use in towplanes (with no warnings about compatibility issues), this stuff, etc. many of which would be answered or clarified to you if you searched this forum for past threads. Other discussion on the pitot switches were posted in another r.a.s. thread just days, including where I quoted Trig on the updated GPS firmware not being intended for gliders with possible low/negative ground speed.

So if you followed what I said you would see I was asking a question. I am not overly familiar with the Trig product line. But I am liking what I am seeing.

I disagree with your statement about the Garmin products. But it’s a moot point since it’s not an appropriate product for gliders.

What I don’t like is when someone asks a question you loudly proclaim, “We’ve talked about this before!� Well if you want to say anything at all why don’t you calmly point out the pertinent conversation? Our how the original poster asked about pitot/static leaks when you install a squat switch. You could have pointed out that a pitot/static check with a calibrated tester is required when installing it.

Happy Thanksgiving by the way! I am off to stuff my face.

It's not that expensive and the installation is trivial.Â* Why the concern?

On 11/28/2019 10:11 AM, Charles Longley wrote:
Ha answered my own question through a little research! Trig recommends an airspeed switch- https://www.trig-avionics.com/librar...ust%202018.pdf
I’ll have to give it some thought before I install one.

--
Dan, 5J

I am thinking about a better mousetrap. Probably can’t do a squat switch on the gear because of the configuration on the ASW20. But I’ll think it over.

On Thursday, November 28, 2019 at 5:30:34 PM UTC-6, Charles Longley wrote:
I am thinking about a better mousetrap. Probably can’t do a squat switch on the gear because of the configuration on the ASW20. But I’ll think it over.

Just an observation, but a true "squat" switch senses the gear bearing the weight of the airframe on the ground. Not just whether the gear is extended or retracted.
another can of worms is documenting such a switch install.

just two cents worth of clarification.
best wishes,
Scott