ADSB visibility with non certified GPS

On Friday, September 22, 2017 at 4:30:19 PM UTC-7, son_of_flubber wrote:
On Thursday, September 21, 2017 at 9:28:52 PM UTC-4, Darryl Ramm wrote:


Well the GPS sources are approved in they may meet say meet TSO-C145 or TSO-C199 or "meets requirements of TSO-C145", or maybe meet none of those of a COTS GPS etc. and that stuff is important to understand.

Trig is correct in what they say. Certified ADS-B In receivers and the ADS-B ground infrastructure will ignore all ADS-B out systems using COTS GPS. Airliners, fast jets, etc. not receiving any of that crap. (that does not stop TCAS seeing the aircraft via transponder interrogation).

The Trig TT22 with 1090ES Out driven by a TN72 GPS source, all properly installed, will be seen by all aircraft with 1090ES In, both portable and certified/fixed install systems. It will also be seen by all aircraft with UAT In if within ADS-R service coverage. However you can only install a TN72 in an experimental aircraft. Certified aircraft, including gliders, requires you use a TN70 as all ADS-B Out installs in certified aircraft must meet 2020 compliance requirements (which effectively require an actual TSO'ed TSO-C145 GPS source in a certified aircraft, including glider).

An ADS-B Out 2020 complaint install (which sticking with Trig, requires a TN70 not a TN72 GPS source) will be seen by all aircraft. Wether that is with a TSO-C145 GPS source (for certified aircraft), or a "meets performance requirements of a TSO-C145 source (an option for experimental aircraft)..... as long as they are all properly installed of course. trig foes not have a lower cost "non-TSO but meets performance requirements of TSO-C145 GPS source".

In an experimental aircraft not intended to fly where the 2020 carriage mandate applies (pop quiz: where do gliders need ADS-B out even with the carriage exemption? No it's not above 10.000') can install any GPS source as long as the ADS-B Out sets the correct quality parameters, and any old COTS GPS will require SIL=0 to be set which will guarantee that is ignored by aircraft with certified ADS-B In systems. It will still be seen by many portable ASD-B receivers, and certainly will be seen by PowerFLARM 1090ES In (assuming we are talking 1090ES Out).

The Trig TN72 is a TABS/TSO-C199 device, it is not TSO-C145, you can not install it in any certified aircraft (including gliders) and you can't use it to meet 2020 Carriage mandate requirements, but you can install it in an experimental aircraft for use outside ADS-B Out required carriage areas (including for gliders anywhere the 2020 carriage exemption lets you fly without compliant ADS-B out)...

And if your experimental glider is so equipped with a TN72 GPS source driving a Trig TT22 and it's properly installed then it *will* paint your glider on certified ADS-B In systems, both via direct 1090ES and via ADS-R for UAT In equipped aircraft. The TT22 importantly also ensures TCAS II systems can issue a RA (resolution advisory) against the glider, a pure UAT Out systems with no transponder cannot and will not cause TCAS to issue an RA.. UAT Out equipped aircraft are also never visible to PowerFLARM (they can trigger PCAS if also transponder equipped), so for that reason avoid UAT Out use in gliders and towplanes.

A properly configured TT22 and TN72 GPS source will also trigger ADS-B ground services for your aircraft when in range of ADS-B ground stations (which won't help at all with PowerFLARM which can't decode any of those ground based services, to receive ADS-R, or TIS-B, or FIS-B ground services you also need a separate ADS-B In/non-PowerFLARM receiver as well as a suitable ADS-B Out system. And with reception on UAT to receive FIS-B).

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On mixed installs with other potential ADS-B Out systems I would want to see the details of what exact ADS-B Out transponder is being used, but a TN72 in an experimental aircraft may well work with multiple different transponder options. TSO-C199 was intended to provide interoperability like that. And that will get you ground services and visibility on certified ADS-B In receivers. But be sure to ask the vendor if not Trig that they guarantee all that works... In practice the way to go today for ADS-B Out in gliders in the USA is to start with a Trig TT22 and use the TN-70 or TN72 and follow Trig's install documentation exactly.

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Unfortunately Trig, who makes great stuff--their TT22 and associated GPS are great products, is saying some stuff that is a little sloppy again, their comment about triggering traffic services for gliders is made without the warning that a PowerFLARM can't receive those services. And they don't qualify TN72 is only for experimental gliders... I wish we had regulations that provided installs of that in certified gliders, as far as I understand we do not. I wish there were regulations (and maybe a STC) that allowed that. I'll talk to Trig and see if they can help be clearer here.


What changes in the above explanation if we substitute TT21 for TT22? I already have a TT21 installed in an Experimental glider.

The TT-21 does not have enough output power to meet the 2020 carriage requirements, so you can't use it to do that (for those remaining areas like Class B or C airspace as mentioned above etc.).

While in an experimental glider you can connect any GPS source you want as long as the system is correctly configured to transmit the GPS parameters. But I'm not sure if the TT-21 firmware is updated to fully work with the TN-72. If it can be used and can transmit a SIL0 quality indicator then it would trigger ADS-B ground services and be seen on certified ADS-B In systems.

You need to check in with Trig support and ask them about all this. Trig are usually very responsive. Swapping out/upgerading the TT-21 to a TT-22 may end up being the best way to go.

Anybody considering installing a transponder in a glider in the USA should be looking at a Trig TT-22 not a TT-21 (and all other brands are really non-starters ). I've talked about this with most USA glider equipment dealers that they should know this, and hopefully are advising purchasers. Trig was blindsided on this, the FAA created this issue with requiring higher 1090ES Output power after the TT-21 was already shipping in the USA.

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And to keep making sure certified glider owners feel bad, doing ADS-B out with a TT-21 in a certified glider is not ever an option as it does not meet the 2020 mandate equipment requirements, regardless of what you want to use it for it must meet those requirement in a certified aircraft.

So glad I bought a TT22 in the first place.Â* I think it was only about
$150 more than a 21.

On 9/22/2017 5:53 PM, Darryl Ramm wrote:
On Friday, September 22, 2017 at 4:30:19 PM UTC-7, son_of_flubber wrote:
On Thursday, September 21, 2017 at 9:28:52 PM UTC-4, Darryl Ramm wrote:

Well the GPS sources are approved in they may meet say meet TSO-C145 or TSO-C199 or "meets requirements of TSO-C145", or maybe meet none of those of a COTS GPS etc. and that stuff is important to understand.

Trig is correct in what they say. Certified ADS-B In receivers and the ADS-B ground infrastructure will ignore all ADS-B out systems using COTS GPS. Airliners, fast jets, etc. not receiving any of that crap. (that does not stop TCAS seeing the aircraft via transponder interrogation).

The Trig TT22 with 1090ES Out driven by a TN72 GPS source, all properly installed, will be seen by all aircraft with 1090ES In, both portable and certified/fixed install systems. It will also be seen by all aircraft with UAT In if within ADS-R service coverage. However you can only install a TN72 in an experimental aircraft. Certified aircraft, including gliders, requires you use a TN70 as all ADS-B Out installs in certified aircraft must meet 2020 compliance requirements (which effectively require an actual TSO'ed TSO-C145 GPS source in a certified aircraft, including glider).

An ADS-B Out 2020 complaint install (which sticking with Trig, requires a TN70 not a TN72 GPS source) will be seen by all aircraft. Wether that is with a TSO-C145 GPS source (for certified aircraft), or a "meets performance requirements of a TSO-C145 source (an option for experimental aircraft).... as long as they are all properly installed of course. trig foes not have a lower cost "non-TSO but meets performance requirements of TSO-C145 GPS source".

In an experimental aircraft not intended to fly where the 2020 carriage mandate applies (pop quiz: where do gliders need ADS-B out even with the carriage exemption? No it's not above 10.000') can install any GPS source as long as the ADS-B Out sets the correct quality parameters, and any old COTS GPS will require SIL=0 to be set which will guarantee that is ignored by aircraft with certified ADS-B In systems. It will still be seen by many portable ASD-B receivers, and certainly will be seen by PowerFLARM 1090ES In (assuming we are talking 1090ES Out).

The Trig TN72 is a TABS/TSO-C199 device, it is not TSO-C145, you can not install it in any certified aircraft (including gliders) and you can't use it to meet 2020 Carriage mandate requirements, but you can install it in an experimental aircraft for use outside ADS-B Out required carriage areas (including for gliders anywhere the 2020 carriage exemption lets you fly without compliant ADS-B out)...

And if your experimental glider is so equipped with a TN72 GPS source driving a Trig TT22 and it's properly installed then it *will* paint your glider on certified ADS-B In systems, both via direct 1090ES and via ADS-R for UAT In equipped aircraft. The TT22 importantly also ensures TCAS II systems can issue a RA (resolution advisory) against the glider, a pure UAT Out systems with no transponder cannot and will not cause TCAS to issue an RA. UAT Out equipped aircraft are also never visible to PowerFLARM (they can trigger PCAS if also transponder equipped), so for that reason avoid UAT Out use in gliders and towplanes.

A properly configured TT22 and TN72 GPS source will also trigger ADS-B ground services for your aircraft when in range of ADS-B ground stations (which won't help at all with PowerFLARM which can't decode any of those ground based services, to receive ADS-R, or TIS-B, or FIS-B ground services you also need a separate ADS-B In/non-PowerFLARM receiver as well as a suitable ADS-B Out system. And with reception on UAT to receive FIS-B).

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On mixed installs with other potential ADS-B Out systems I would want to see the details of what exact ADS-B Out transponder is being used, but a TN72 in an experimental aircraft may well work with multiple different transponder options. TSO-C199 was intended to provide interoperability like that. And that will get you ground services and visibility on certified ADS-B In receivers. But be sure to ask the vendor if not Trig that they guarantee all that works... In practice the way to go today for ADS-B Out in gliders in the USA is to start with a Trig TT22 and use the TN-70 or TN72 and follow Trig's install documentation exactly.

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Unfortunately Trig, who makes great stuff--their TT22 and associated GPS are great products, is saying some stuff that is a little sloppy again, their comment about triggering traffic services for gliders is made without the warning that a PowerFLARM can't receive those services. And they don't qualify TN72 is only for experimental gliders... I wish we had regulations that provided installs of that in certified gliders, as far as I understand we do not. I wish there were regulations (and maybe a STC) that allowed that. I'll talk to Trig and see if they can help be clearer here.

What changes in the above explanation if we substitute TT21 for TT22? I already have a TT21 installed in an Experimental glider.
The TT-21 does not have enough output power to meet the 2020 carriage requirements, so you can't use it to do that (for those remaining areas like Class B or C airspace as mentioned above etc.).

While in an experimental glider you can connect any GPS source you want as long as the system is correctly configured to transmit the GPS parameters. But I'm not sure if the TT-21 firmware is updated to fully work with the TN-72. If it can be used and can transmit a SIL0 quality indicator then it would trigger ADS-B ground services and be seen on certified ADS-B In systems.

You need to check in with Trig support and ask them about all this. Trig are usually very responsive. Swapping out/upgerading the TT-21 to a TT-22 may end up being the best way to go.

Anybody considering installing a transponder in a glider in the USA should be looking at a Trig TT-22 not a TT-21 (and all other brands are really non-starters ). I've talked about this with most USA glider equipment dealers that they should know this, and hopefully are advising purchasers. Trig was blindsided on this, the FAA created this issue with requiring higher 1090ES Output power after the TT-21 was already shipping in the USA.

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And to keep making sure certified glider owners feel bad, doing ADS-B out with a TT-21 in a certified glider is not ever an option as it does not meet the 2020 mandate equipment requirements, regardless of what you want to use it for it must meet those requirement in a certified aircraft.




--
Dan, 5J

Dan- You pretty much HAD to buy the TT22, as the 250 watt transmit is required for altitudes over 10,000 MSL. And out here in Moriarty, we are tempted to put the landing gear down if we get below that!

On 09/23/2017 09:27 AM, wrote:
Dan- You pretty much HAD to buy the TT22, as the 250 watt transmit is required for altitudes over 10,000 MSL. And out here in Moriarty, we are tempted to put the landing gear down if we get below that!


Trig says the TT21 is good to 15,000 msl, but yeah, the cost and average
current consumption of the TT22 are only slightly higher for the TT22.
I wouldn't consider a TT21 for a new installation, even forgetting about
the ADS-B issue.

My mistake- the 175 watt units are good to 15,000 MSL, 200+ watts necessary above that. So, Moriarty and most high altitude western US sites with potential flight altitudes to 17,999 MSL (and higher in ARTCC authorized airspace such as wave windows or SAGE II clearance in the Sierra Nevada Wave etc.) would imply utilization of the higher transmit power of the TT22 over the TT21.

On Saturday, September 23, 2017 at 6:20:38 PM UTC-7, wrote:
My mistake- the 175 watt units are good to 15,000 MSL, 200+ watts necessary above that. So, Moriarty and most high altitude western US sites with potential flight altitudes to 17,999 MSL (and higher in ARTCC authorized airspace such as wave windows or SAGE II clearance in the Sierra Nevada Wave etc.) would imply utilization of the higher transmit power of the TT22 over the TT21.

Yes but nobody really cares about this, and lots of lower power transponders have been flying in gliders for years and provide good visibility to ATC and TCAS etc.

The pressing reason to use a TT22 over a TT21 is for ADS-B Out compliance, especially in a certified glider the TT21 cannot be installed or used for ADS-B Out for any purpose.You will not get installation approval for it, and I don't want folks having tears when they discover that.

The important things are focusing in safety and installing and using a transponder at all if you are near busy airspace. Please install and use whatever transponder you have/can get/afford. For ADS-B future use reasons it is a good idea to install a TT-22.

If I read the Trig website correctly the tt21 is approved for adsb-out just about everywhere on the planet except the USA. So if someone brings their certified glider from their home country are they legal to fly in the USA or must they comply with USA requirements?

On Saturday, September 23, 2017 at 7:33:27 PM UTC-7, Dave White wrote:
If I read the Trig website correctly the tt21 is approved for adsb-out just about everywhere on the planet except the USA. So if someone brings their certified glider from their home country are they legal to fly in the USA or must they comply with USA requirements?

Is there light at the end of this rat hole? But the answer is going to be comply with US regulations. The more detailed answer of course is you are going to discuss this with an FAA representative.

And there is no such thing as just a TT-21 install for ADS-B out.What is the GPS source? I expect many gliders flying outside the USA who have ADS-B Out have a COTS GPS source, and that likely a worse issue, who knows what they set SIL etc. to. Not only will that not be valid in a certified equivalent aircraft in the USA but it may well get you noticed by the feds.

On Thursday, September 21, 2017 at 7:31:32 PM UTC-7, Darryl Ramm wrote:
Walt, I think you are misunderstanding what Trig wrote. A TN72 GPS Source will be seen by everybody. That is why anybody doing ADS-B Out in an experimental glider with a TT22 should be equipping with at least a TN72 (or TN70, TN70 required for certified gliders).

Darryl,

OK, I'm clear now that a TN72 GPS Source from a Trig T22 will make me officially visible to all ADS-B in equipped aircraft.

I am still trying to figure out why I would want to equip with any kind of ADS-B out in my T22 equipped glider:

1) It would be great (but not necessary) to be seen by all ADS-B equipped aircraft. But, with ADS-R (rebroadcast) won't those other aircraft see me anyway since I'm equipped with a Mode-S Trig transponder? I suppose at low altitude where ADS-R is not available, direct receipt of my ADS-B out would be an advantage.

2) It sounds like with the TN72 GPS source, I will not be compliant if wanting to enter Class B, C, and a few other little used airspace. My question is this... If equipped with a TN72 GPS source, do you think that ATC will allow temporary access to Class B and C... such a for passing through their airspace? That was ONE reason for equipping with a transponder in the past.. I have no intention of OPERATING in Class B and C so as to use full ATC services. Also, do you think that controllers for restricted airspace MIGHT allow transiting that airspace without fully compliant ADS-B out?

If ATC uniformly will disallow temporary transiting of Class B, C and restricted airspace unless equipping with a fully compliant GPS source (i.e. TN70), then there is VERY LITTLE REASON TO EQUIP WITH A TN72.

I see small potential justification for equipping with a TN72:

A) visibility to all ADS-B official aircraft directly without rebroadcast (ADS-R) which means they can see me in the pattern a low altitude.

B) Potenially, a TN72 will also give me an alternative to a Satellite tracker if Flight Aware or Aerion makes tracking of ADS-B aircraft less expensive than the current vendors (Spot and Garmin Inreach).

comments...

Walt Rogers WX

On Sunday, September 24, 2017 at 11:59:19 AM UTC-7, WaltWX wrote:
On Thursday, September 21, 2017 at 7:31:32 PM UTC-7, Darryl Ramm wrote:
Walt, I think you are misunderstanding what Trig wrote. A TN72 GPS Source will be seen by everybody. That is why anybody doing ADS-B Out in an experimental glider with a TT22 should be equipping with at least a TN72 (or TN70, TN70 required for certified gliders).

Darryl,


Everybody need to stop saying "ADS-B Out" and say 109ES Out or UAT Out where it matters. I try to only say ADS-B where the link layer does not matter. Saying "ADS-B" where you need to be clear about 1090ES or UAT is as useful as saying "TSO" without being clear if we are talking about TSO-C145 or TSO-C199, and can cause much confusion.

OK, I'm clear now that a TN72 GPS Source from a Trig T22 will make me officially visible to all ADS-B in equipped aircraft.

Well all aircraft with 1090ES In, or via ADS-R if they have UAT In (and it's properly set up with some type of ADS-B Out etc.) and in range of ADS-B ground stations.

I am still trying to figure out why I would want to equip with any kind of ADS-B out in my T22 equipped glider:

1) It would be great (but not necessary) to be seen by all ADS-B equipped aircraft. But, with ADS-R (rebroadcast) won't those other aircraft see me anyway since I'm equipped with a Mode-S Trig transponder? I suppose at low altitude where ADS-R is not available, direct receipt of my ADS-B out would be an advantage.

ADS-R no, you are confusing ADS-R and TIS-B.

TIS-B broadcasts information for SSR targets, it requires
1. Your aircraft has a transponder
2. Your aircraft is within SSR coverage
3. The TIS-B client aircraft has ADS-B In
4. The TIS-B client aircraft has ADS-B Out that is correctly configured to describe it's ADS-B In capabilities.

TIS-B position reports are SSR based and should be expected to be less accurate than either ADS-B direct or ADS-R.

There are many places where gliders and gliders, or towplanes or GA aircraft that might have 1090ES In will be together that won't have TIS-B service coverage. Think of lots of GA airports that glider operations may tow out of or gliders may land at. And many busy airports I can think of where you lose SSR coverage as you decent to pattern height, they concern me as pilots may stop seeing TIS-B targets and be lulled into assurance the target is not longer a threat. Ditto for aircraft without properly configured ADS-B Out that are piggybacking on nearby aircraft to cause TIS-B (and ADS-R) message broadcasts, things going quiet on the traffic displays does no mean there is no traffic.

2) It sounds like with the TN72 GPS source, I will not be compliant if wanting to enter Class B, C, and a few other little used airspace. My question is this... If equipped with a TN72 GPS source, do you think that ATC will allow temporary access to Class B and C... such a for passing through their airspace? That was ONE reason for equipping with a transponder in the past. I have no intention of OPERATING in Class B and C so as to use full ATC services. Also, do you think that controllers for restricted airspace MIGHT allow transiting that airspace without fully compliant ADS-B out?

Don't know, talk to your local ATC folks.

If ATC uniformly will disallow temporary transiting of Class B, C and restricted airspace unless equipping with a fully compliant GPS source (i.e. TN70), then there is VERY LITTLE REASON TO EQUIP WITH A TN72.

Again I talk to your local ATC folks. I would not want to ask any national authorities about uniform ATC treatment if any special situation. Work out things locally and use that to guide what you do.

I see small potential justification for equipping with a TN72:

A) visibility to all ADS-B official aircraft directly without rebroadcast (ADS-R) which means they can see me in the pattern a low altitude.

But you still won't be seen by aircraft in those situations. that only have UAT In. You *need* ADS-R ground service coverage for that.

B) Potenially, a TN72 will also give me an alternative to a Satellite tracker if Flight Aware or Aerion makes tracking of ADS-B aircraft less expensive than the current vendors (Spot and Garmin Inreach).

The current Garmin InReach tracker is relatively low cost and already more capable (esp. two way messaging and reliable operation on the ground (as long as you have line of sight of satellites) than what ADS-B will be able to do. Having ADS-B Out is further information, that might be be very useful in a SAR situation. I would certainly include that in discussions with club members, FBOs, written down as part of your emergency information/plan that you have (everybody has one right?) make sure it is noted on your NOAA ELT/PLB registration, SPOT or InReach tracker registration, etc. But I'd not be upgrading to 1090ES Out for SAR reasons--I'd buy a Garmin InReach first if I did not already have one.

And the FAA/SAR organizations today can get to ADS-B flight traces, so if an ADS-B out equipped glider should go missing it's important to make sure SAR groups are aware that it was so equipped.

comments...

Walt Rogers WX

You may also want to have 109ES Out to provide better long-term visibility via PowerFLARM when buddy flying.

Many aircraft are going to equip with ADS-B Out by 2020. I'm anecdotally seeing a lot of GA aircraft equip with ADS-B In, with most new potable and fixed systems being dual-link receive. Given all that if you fly near busy GA aircraft areas I expect equipping with ADS-B Out to be interesting to consider, fast jets and airliners can see you today via TCAS, in all airspace at all times. 1090ES Out starts also providing that "all airspace and all time" capability to GA aircraft as they equip with (1090ES or dual-link) ADS-B In.