There are no TABS/TSO-C199 installation or use regulations in the USA so TSO-C199 products being introduced into the market are not that intersting. A Trig TT-21 or TT-22 will meet TABS Class A device requirements since they are effectively meet the TSO requirement in being full Mode-S transponders. But again we need to see actual regulations to see how stuff will work. The Trig TN72 *is* a TSO-C199 Class B (e.g. GPS) device. But again that TSO is not the same as having a TSO-C166b (1090ES Out) and give you no 2020 Mandate compliance in any aircraft. Neither can you actually install in in any certified aircraft. If you have an experimental glider and want to play with ADS-B Out in the USA then the Trig TT-22 and TN72 looks like the way to go right now.

No the UK EC program is not the same as TABS. TABS Class A devices (the Class B part is just the GPS) both feature a reduced functionality Mode-S transponder and 1090ES Out. And are compatible with both TCAS and the FAA ADS-B system, including being enough to get client services for TIS-B and ADS-R (which yes PowerFLARM can't receive anyhow). The uAvionix Skylym Echo ATT-20B is 1090ES Out and In only with no basic Mode-S transponder support. So not TCAS RA compatibility and unclear if its enough to trigger FAA based ADS-B ground services. Lack of TCAS compatibility is a dangerous shortcoming when worrying about flight near busy airspace. It's also not possible to add that uAvionix device to an aircraft with a separate transponder (they could interfere with each other). I expect/hope the FAA focus in on TABS regulations in the USA.

uAvionix have a problem with how they dribble bull**** like: "Worlds first approved ADS-B Out Solution" ah right, if you ignore all the other ADS-B Out systems from all those other manufacturers. It's hard to take them seriously when they do stuff like that, and they have a history of such silliness..



On Tuesday, December 6, 2016 at 9:54:24 AM UTC-8, vontresc wrote:
On Saturday, December 3, 2016 at 11:10:22 PM UTC-6, Darryl Ramm wrote:
Hi Renny

Great question. Here is a long-winded way of saying I don't know the answer :-) But maybe it recaps some useful stuff.

I don't see how it could be "illegal" there is no law or regulation I'm aware of saying you can't do this in an experimental aircraft. What exact ground services you would receive, wether its a good idea or would upset folks, etc. I don't know.

For completeness let me just mention the relevant 1090ES part of the ADS-B carriage regulations here.

14 CFR 91.225 requires 1090ES Out TSO-C166b Class A1, A1S, A2, A3, B1S, or B1 devices, or "meets performance of" for experimental aircraft. And yes the "Class" spec includes power output but also other stuff, For example Class A devices are ADS-B Out and In (think transport category aircraft), Class B devices are ADS-B Out only.

The Trig TT-22 is TSO-C166b Class B1S device
The Trig TT-21 is TSO-C166b Class B0 device -- so does not meet the requirement.

Requiring higher-power 1090ES Out devices allowed the FAA to save money by requiring fewer ADS-B ground stations. My understanding was Trig was surprised by this FAA requirement that came into effect after they were already selling the TT-21 in the USA.

And none of this changes any usefulness of the TT-21 as a plain transponder before or after 2020. If you are flying with a Trig TT-21 transponder in a glider today, you already have a fantastic device for providing traffic information about your glider to ATC SSR and TCAS and PCAS systems and via TIS-B to suitably equipped aircraft. Obviously some of those things only work when within appropriate service coverage... but TCAS is great technology or last resort in part because it works *everywhere*. And none of that goes away in 2020.... but some ATC SSR is expected to be decommissioned in the longer term.

----

So you can today use a TT-22 but not a TT-21 to meet the FAA 2020 ADS-B Out carriage requirements, but as you point out gliders are currently exempt from most of those requirements.

For an experimental aircraft, you can in principle connect up any GPS source to an ADS-B out system as long as you correctly configure the GPS source to reflect it's quality parameters like SIL. Transmitting lies about the GPS data or it's quality is just stupid and is really going to **** off the FAA and may earn you a visit from some feds. Lets see if anything is left of NavWorx after the FAA finishes chewing on them for their apparent decision to transmitting false GPS SIL etc. data. This is where you absolutely should not be guessing or messing around. Make sure you work with manufacturers instructions for doing that, and if in doubt check with them (start with the transponder manufacture).

I can't recall that the ADS-B device class being transmitted in any ADS-B extended squitter messages. There may be some ways to reverse engineer this is you are also interrogating the underlying mode S transponder. I'd have to dig though too much stuff now to check. I have no idea if the FAA ADS-B ground infrastructure would transmit TIS-B or ADS-R for client aircraft if it knew that a 1090ES device was "under-spec" at Class B0. I suspect they might not care/look at that, they certainly do care/look at the GPS source spec data (like SIL) and that is clearly transmitted. This would be interesting to ask FAA folks about...

And just playing with this is certainly not what I'd do. I'd be talking to Trig and local FSDO folks to make sure they are all OK with this any "experimenting". A TT-21 with a TN71 is really an early version of a TABS device, so asking the right questions might help find Trig and FAA folks interested in working with anybody who wanted to play with this.

It's certainly my hope that *if* gliders lose their ADS-B Out exemption that TABS regulations are introduced that would hopefully help provide a lower-cost/easier to install etc. method of compliance. Of course I'd also like to see TABS regulations introduced even if the ADS-B Out exemption was not removed.

The folks at Trig have been very helpful every contact I've had with them, and they are a great place to start asking with these questions if you own a TT-21 today.


Darryl


On Saturday, December 3, 2016 at 4:54:13 PM UTC-8, Renny wrote:
On Saturday, December 3, 2016 at 4:41:22 PM UTC-7, Darryl Ramm wrote:
On Thursday, December 1, 2016 at 5:11:44 PM UTC-8, glidergreg wrote:
On Saturday, July 30, 2016 at 12:22:22 AM UTC-5, Mike Schumann wrote:
I spent a day at Oshkosh last Monday and had a chance to talk to Trig about their ADS-B plans.

The Trig TT22 Mode S Transponder is currently shipping and supports 1090ES ADS-B Out, if it is connected to an approved WAAS GPS position source. Up to now, approved GPS sources have been quite expensive.

The good news is that around Christmas, Trig is going to start shipping their new, as yet unannounced, TN72 GPS position source. I had a chance to see a prototype. It easily fits in the palm of your hand, weighs about 100 grams, and uses minimal power. While Trig wouldn't commit to a price, the people I talked to said that the unit would sell for less than $600.