Sarah,

Thanks for the explanation... but... I'm still confused. Try explaining it one more time.

It sounds like having TABS with your Trig in a glider will make you more visible to other aircraft who can track ADS-B out messages. The Mode S transponder already gives an equipped glider visibility to TCAS.

Now, in a Mode S equipped glider, I can request a clearance to enter Class A,B, C, or restricted airspace ... but in the future after 2020... will that clearance be denied UNLESS I have a TSO-C166B ADS-B out device? I would hope that FAA or ATC would allow clearances to enter/transit Class A,B,C and restricted airspace WITH a TABS device.

So, to me... this sounds like a very minimally beneficial upgrade to my Trig setup. I wonder... will TABS devices be visible to the satellite based ADS-B tracking service? If so, it might replace other satellite tracking devices like Spot and Delorme/Garmin InReach.

My two cents...

Walt Rogers WX

On Tuesday, January 3, 2017 at 2:29:07 PM UTC-8, Sarah wrote:
I should clarify after some study of 91.225 for gliders.

http://www.ecfr.gov/cgi-bin/text-idx..._1225&rgn=div8

TABS is always voluntary.

After 2020 a TSO-C166b 1090es ADS-B out (not just TABS or UAT) will be required

- In class A, above FL180. Presumably IFR without a wave-window.

Either 1090es or UAT (but not TABS) is acceptable

- Inside class B or class C airspace, or within that lateral boundary above 10,000' MSL (or the airspace ceiling, whichever is lower.)

Otherwise as with a transponder today, ADSB-out of any kind will not be required within the class B "veil" or generally in controlled airspace between 10,000' and 18,000' MSL.

Whew!