On Tuesday, June 16, 2015 at 10:44:47 AM UTC-7, Steve Leonard wrote:
On Tuesday, June 16, 2015 at 11:32:16 AM UTC-4, jfitch wrote:

Many who have fitted Mode-S transponders already have the equipment and electrical load to transmit position and velocity data to the collision avoidance system. If Flarm would just certify their GPS as TSO-C199 compliant, then many of us would already have the equipment required.

Nope, Jfitch. You would not. TABS will transmit your position for a TCAS enabled plane to see. Flarm does not do that. Only way to do that now is with a transponder. Maybe in a couple of years (the TSO for TABS was just released in October of 2014), there will be a complete, TABS system available. But, it will have to cost a whole bunch less than a transponder to draw any real interest in adoption.

On Tuesday, June 16, 2015 at 12:19:19 PM UTC-5, son_of_flubber wrote:

Is it reasonable to argue that a Trig TT21 (130 watt) should be acceptable for glider use due to my lower speed, rather than just the TT22 (250 watt)? Is there any chance that the FAA would grandfather in TT21s in any new regulations?


Son, your transponder (TT21) is already acceptable. No need to "grandfather" it.

Does PowerFlarm alert to TABS equipped aircraft?

No. PowerFlarm will not alert TABS equipped aircraft. PowerFlarm only "alerts" other Flarm devices as to your presence. TABS will be a "dumb" system, as it only talks. It does not listen. It will tell the heavies "Look out! Something is out here!" But it will not tell you "Look out! Something is trying to run over you!"

My read on this based on my current understandings.

Steve Leonard

I was not suggesting that the Flarm alone would alert TABS equipped aircraft, but the GPS already installed in the Flarm could be used as a GPS source for your already installed Mode S transponder, all that is then required is a cable.

The best solution for both gliders and light power is exactly this - using the installed Mode S capability as a transmitter and cheap GPS for not as capable - but still perfectly adequate for collision avoidance - substitute for ADS-B out.