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  #11  
Old January 5th 19, 06:26 PM posted to rec.aviation.soaring
Andrzej Kobus
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On Saturday, January 5, 2019 at 10:40:44 AM UTC-5, wrote:
On Saturday, January 5, 2019 at 7:16:12 AM UTC-8, Dan Marotta wrote:
If you do any wave flying a software switch is not a good option. On my
most recent wave flight I saw ground speeds as low around 8 kts.Â*
Imagine the FAA's annoyance when you "land" at 18,000 feet! Imagine the
thrill of the pilot of the aircraft on a collision course when he "sees"
you on the "ground" and stops looking outside for you.

The Peregrine switch is outrageously expensive (about $180) for what you
get, and with some shopping, you might find a suitable alternative,
especially in an Experimental glider.Â* After all, it's a simple pressure
operated On/Off switch.Â* One wire runs from the transponder to the
switch to ground.

On 1/5/2019 5:18 AM, wrote:
On Thursday, January 3, 2019 at 11:10:40 PM UTC-8, Darryl Ramm wrote:
On Thursday, January 3, 2019 at 6:54:47 PM UTC-8, wrote:
I attended the the AOPA Fly-in at Santa Fe this year and spoke to both the Trig representative and some knowledgeable FAA folks about the ADS-B options for certified gliders vs. those with Experimental classification. The interpretation that the Trig 22 with the TN-70 is the only legal 2020 Compliant option for certified gliders came into question. After the FAA rep closely read the requirements, I was advised that the much cheaper TN-72 might be a viable choice. His interpretation indicated that a certified aircraft that is not absolutely required to install ADS-B Out (read: Glider), and does NOT have a generator fed electrical system would be considered legal with the TN-72.

Since this is the only time I have received this answer, and all other documentation I have seen indicates that an installation in a certified glider requires the more expensive TN-70. I would appreciate other input. Darryl Ramm seems to be the "go to guy" for ADS-B information. Your thoughts?
Please ask the folks telling you this how you get that opinion in writing and in a way usable by say an A&P to know they are OK. This is not something that a local FSDO is likely to make with, they pretty much focus on following AFS-360_2016-03-02. Once well outside that this is stuff for others.

So the argument goes... As PIC I'm not required to comply with 14 CFR 91.225 so 14 CFR 91.227 does not apply to me and so I don't need to follow AFS-360_2016-03-02... so I'll just go ahead. and install a SIL=3 output TN72 in a glider. My A&P does not need to file the ADS-B Out install 337 because that's a AFS-360_2016-03-02 policy requirement. And they don't have to follow that policy.... well if you can find an A&P who agrees with that.... go for it. I can see the placard now "The ADS-B Out install in this aircraft does not comply with 14 CFR 91.217..." The FAA ADS-B monitoring system will likely quickly catch that there was no '337 filed for that SIL=3 install in a type certified aircraft and they'll want to know where/who did the install. So may be the quickest way fo find out the FAA's interpretation of all this :-) OK maybe not the wisest thing to do.

I'm not necessarily a believer that legal interpretation is correct, and this has never got to a court or FAA Office of the Chief Counsel for an opinion. A request to the Office of Chief Counsel for an interpretation would be the next step for an organization that cared about this. Even if the FAA agreed, not everybody will want to waive full 91.225 flight privileges. Some glider owners do want flight privileges in Class A, close above Class C or lowered Class B ceilings (e.g. Seattle), etc.

What is clear today in a type certified glider is the TN70+TT22 install with full AFS-360_2016-03-02 compliance get you everything. For other uses the TN72 SIL=1/TABS install is doable, but with reduced functionality.. Part of the simple (non-legal) justification of the legitimacy of a TABS install, e.g. when explaining to FSDO staff, is the argument that the FAA created the whole TABS TSO-C199 approval to exactly allow this, and it's all simply orthogonal to 91.225 and 91.227.


For experimental gliders to fly in 'adsb airspace' after 2020, the Trig website guidance (below) is to use an uncertified puck gps antenna, TN72, and TT22 with SIL=3 setting. Also an 'airspeed switch', but they aren't clear if this must be hardware or can be the software setting of the TT22..

https://www.trig-avionics.com/librar...ust%202018.pdf

--
Dan, 5J



I'm not interested in wave flying, so personally I would use the free software 'switch' on the Trig 22 setup menu, if it will satisfy FAA requirements.

But I did find this airspeed switch that is a lot cheaper than the Peregrine switch:

https://www.aircraftspruce.com/catalog/elpages/asw2.php


The software switch should never be used in a glider. We are flying to slow for it to work properly. The switch you included the link to is a good one..
  #12  
Old January 5th 19, 07:33 PM posted to rec.aviation.soaring
Darryl Ramm
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Using GPS groundspeed to determine airborne status with these Trig installs is a frogging mess. I like Trig products but this is a cluster**** that should have been documented long ago. It’s not just wave flying, a strong headwind can have the ADS-B Out transmitting it is on the ground.

The “correct” thing to do...

If a 2020 compliant install with a TN72 (in an experimental glider) use the Pereguine STC kit for the TN70. Which is really just a pitot pressure “squat” switch and some t-adapters and pneumatic house pieces. The TT22 documentatin describes it connected between pin 19/ground. Test this with the transponder set to “ON”. As you (cough, carefully) apply pitot pressure you should see the transponder display switch from GND to ATL as the ASI passes about 27 knots. The pressure switch is easy to install, make sure it is connected with correct orientation (marked on the switch) between the pitot and static lines, easiest place is often just behind the ASI.

Any TT22/TN70 installs should be following the STC and using the pitot squat switch anyhow.

2020 Compliant installs are required by 14 CFR 91.227 to automatically switch between air and ground modes, it’s not clearly written there but it is an implied requirement.

If you are doing a TABS/SIL=1 install you are not required to have that automatic air/ground determination and can just set the squat switch to none or not connected (I can’t remember the exact value name) in the TT21/22 setup. That will transmit airborne messages at all times including when in the ground... as specifically allowed by TSO-C199.

If you are doing a SIL=0 install (to what save a few hundred dollars on a TN72)... ah your an idiot, and I am being polite.

I have explained to all the glider market Trig dealers in the past the importance of them selling a TN70 STC kit squat switch with any TN72 intended for every SIL=3/2020 compliant install. And I have pointed out to them how they order the kit through Edmo. If your dealer is not doing this, not asking or explaining this to you when you buy a TN72 then find a better dealer..

If folks want to use/source a different pressure switch that’s entirely possible, but I cannot reconnect any specific options there.

  #13  
Old January 5th 19, 10:45 PM posted to rec.aviation.soaring
Darryl Ramm
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On Saturday, January 5, 2019 at 10:33:58 AM UTC-8, Darryl Ramm wrote:
Using GPS groundspeed to determine airborne status with these Trig installs is a frogging mess. I like Trig products but this is a cluster**** that should have been documented long ago. It’s not just wave flying, a strong headwind can have the ADS-B Out transmitting it is on the ground.

The “correct” thing to do...

If a 2020 compliant install with a TN72 (in an experimental glider) use the Pereguine STC kit for the TN70. Which is really just a pitot pressure “squat” switch and some t-adapters and pneumatic house pieces. The TT22 documentatin describes it connected between pin 19/ground. Test this with the transponder set to “ON”. As you (cough, carefully) apply pitot pressure you should see the transponder display switch from GND to ATL as the ASI passes about 27 knots. The pressure switch is easy to install, make sure it is connected with correct orientation (marked on the switch) between the pitot and static lines, easiest place is often just behind the ASI.

Any TT22/TN70 installs should be following the STC and using the pitot squat switch anyhow.

2020 Compliant installs are required by 14 CFR 91.227 to automatically switch between air and ground modes, it’s not clearly written there but it is an implied requirement.

If you are doing a TABS/SIL=1 install you are not required to have that automatic air/ground determination and can just set the squat switch to none or not connected (I can’t remember the exact value name) in the TT21/22 setup. That will transmit airborne messages at all times including when in the ground... as specifically allowed by TSO-C199.

If you are doing a SIL=0 install (to what save a few hundred dollars on a TN72)... ah your an idiot, and I am being polite.

I have explained to all the glider market Trig dealers in the past the importance of them selling a TN70 STC kit squat switch with any TN72 intended for every SIL=3/2020 compliant install. And I have pointed out to them how they order the kit through Edmo. If your dealer is not doing this, not asking or explaining this to you when you buy a TN72 then find a better dealer.

If folks want to use/source a different pressure switch that’s entirely possible, but I cannot reconnect any specific options there.


And to make clear I appreciate that flow chart from Trig, it lays things out well. And I'd seen an early version of that/had discussions with the Trig marketing folks. It's the other main documentation that does not make clear that a pitot pneumatic switch is a good idea is what frustrates me.

Having your ADS-B Out transmitting ground not air mode messages while airborne is a potential safety hazard and will certainly eventually get you a polite please explain letter from the FAA ADS-B surveillance folks.

The FAA ADS-B flight reports (https://adsbperformance.faa.gov/paprrequest.aspx) will flag mistakes like the ADS-B Out transmitting in ground mode during flight very clearly, so always get one or more of those after doing an ADS-B Out install. And not just for 2020 Compliance, do that checking for TABS or SIL=0 installs as well (TABS and SIL=0 reports will be flagged with multiple red items as not 2020 Compliant... that's what you *want* to see for them). Anybody can email me the PDF report for their flight to help check it over. But tell me what you are trying to achieve (2020 Compliance, TABS etc.).

All this GPS groundspeed squat switch stuff was really noticed in the very first TN72 install I helped with way back whenever in Ramy Yanetz's ASG29, it was quickly obvious using the GPS groundspeed is broken for use in gliders. That experience largely triggered that Trig flowchart recommendation. (Thanks Ramy for being a guinea pig).


  #14  
Old January 6th 19, 09:14 AM posted to rec.aviation.soaring
bumper[_4_]
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Default pure gliders with ads b?

On Saturday, January 5, 2019 at 7:16:12 AM UTC-8, Dan Marotta wrote:
..

The Peregrine switch is outrageously expensive (about $180) for what you
get, and with some shopping, you might find a suitable alternative,
especially in an Experimental glider.Â* After all, it's a simple pressure
operated On/Off switch.Â* One wire runs from the transponder to the
switch to ground.



Here's one source for an inexpensive ($24) and small "water column range" pressure switch. The MDA-011 should work fine (I'm using a similar switch to run a Hobbs meter to show actual flight time. Another is being used to monitor the cooling air to an engine.

http://www.dwyer-inst.com/Product/Pr...ches/SeriesMDA

bumper

  #15  
Old January 6th 19, 05:25 PM posted to rec.aviation.soaring
Matt Herron Jr.
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Posts: 548
Default pure gliders with ads b?

On Sunday, January 6, 2019 at 12:14:34 AM UTC-8, bumper wrote:
On Saturday, January 5, 2019 at 7:16:12 AM UTC-8, Dan Marotta wrote:
.

The Peregrine switch is outrageously expensive (about $180) for what you
get, and with some shopping, you might find a suitable alternative,
especially in an Experimental glider.Â* After all, it's a simple pressure
operated On/Off switch.Â* One wire runs from the transponder to the
switch to ground.



Here's one source for an inexpensive ($24) and small "water column range" pressure switch. The MDA-011 should work fine (I'm using a similar switch to run a Hobbs meter to show actual flight time. Another is being used to monitor the cooling air to an engine.

http://www.dwyer-inst.com/Product/Pr...ches/SeriesMDA

bumper


I think you need a differential pressure switch to avoid the problem of changing pressure with altitude. This one appears to have only one input.
  #16  
Old January 6th 19, 07:15 PM posted to rec.aviation.soaring
Darryl Ramm
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Posts: 2,403
Default pure gliders with ads b?

Yes better be differential, have the right trip point, tolerance, longevity, and some basis for knowing the thing is suitable to install in an aircraft in critical pitot plumbing... or... I know pay $125 for the Pereguine kit and spend time worrying about more important stuff.
  #17  
Old January 7th 19, 06:44 PM posted to rec.aviation.soaring
[email protected]
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On Sunday, January 6, 2019 at 10:15:39 AM UTC-8, Darryl Ramm wrote:
Yes better be differential, have the right trip point, tolerance, longevity, and some basis for knowing the thing is suitable to install in an aircraft in critical pitot plumbing... or... I know pay $125 for the Pereguine kit and spend time worrying about more important stuff.


Does anyone know why a $125 squat switch is important for a glider (other than the FAA saying so?)

I found several uncertified pitot pressure switches online, eg MDS-0, MDA111, PSF100A. They can be found for less than $20, rated for about 20 million cycles. A suitable trip point pressure is 1" H20 column, which corresponds to 39kts airspeed. Or 0.5" corresponds to 28kts.
  #18  
Old January 8th 19, 04:26 PM posted to rec.aviation.soaring
Dan Marotta
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I thought we were talking "certificated" here.Â* That would mean, to me
at least, that a licensed mechanic's signature is required in the log
book.Â* I think there are also regulations about transponder
installations which, to me, are ridiculous, e.g., I can remove and
replace a radio as the owner/operator of the aircraft, but not a
transponder.Â* So, if you can find a mechanic who's willing to put his
license on the line to save you a hundred bucks, have at it. But if you
have a near miss with another aircraft while your transponder is
reporting that you're on the ground...

I know it's silly, but those are the rules.

On 1/7/2019 10:44 AM, wrote:
On Sunday, January 6, 2019 at 10:15:39 AM UTC-8, Darryl Ramm wrote:
Yes better be differential, have the right trip point, tolerance, longevity, and some basis for knowing the thing is suitable to install in an aircraft in critical pitot plumbing... or... I know pay $125 for the Pereguine kit and spend time worrying about more important stuff.

Does anyone know why a $125 squat switch is important for a glider (other than the FAA saying so?)

I found several uncertified pitot pressure switches online, eg MDS-0, MDA111, PSF100A. They can be found for less than $20, rated for about 20 million cycles. A suitable trip point pressure is 1" H20 column, which corresponds to 39kts airspeed. Or 0.5" corresponds to 28kts.


--
Dan, 5J
  #19  
Old January 8th 19, 08:02 PM posted to rec.aviation.soaring
Charlie M. (UH & 002 owner/pilot)
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US government, who said it had to make sense?!?!

LOL........
  #20  
Old January 9th 19, 12:11 AM posted to rec.aviation.soaring
Scott Williams
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On Tuesday, January 8, 2019 at 1:02:55 PM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
US government, who said it had to make sense?!?!

LOL........


I heard once the F.A.A motto, We're not happy until You're not happy.
Cheers.
 




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