On Wednesday, May 2, 2018 at 6:23:29 PM UTC-7, Tom BravoMike wrote:
At the most basic level FLARM is transmitting GPS data and looking at other FLARM units GPS data.... the antennas are not directional etc. It's all about software and focus on the glider community and making the traffic warnings usable/reducing false positives and providing the NMEA based data integration with glider traffic displays and glider flight computers... nothing those other systems can do. (...)

Thank you for taking your time to clarify it to me. You are right, I have not flown in a FLARM equipped glider yet. But I find this your statement very important and revealing to me: "It's all about software and focus on the glider community". So the questions that bothers me all the time is: with the ADS-B becoming so common and mandatory for most aircraft, why should I have two transmitting systems on board (FLARM and a transponder - think about price and power usage). If it's all about software, why can't we have software using the ADS-B transmission (more universal, stronger ergo better visible) to provide us, glider pilots, with the information (visual/acoustic) equal to that produced by FLARM.

Let me make it clear: I am for the safety, visibility, awareness etc. I have a Microair Mode C Transponder and the ATD-300 Traffic Watch working beautifully, and I know it's not enough. I'm not against the idea behind FLARM and I bow down before the guys who invented and implemented it - but now it's the NextGen and ADS-B era - let's adapt to it! If a FLARM device appears on the market with the added ADS-B-Out feature, I'll be among the first to order, ready to invest in it whatever is necessary and justified.

Thanks for equipping with a transponder... that's actually a huge help near airliners, fast jets, military traffic etc. and while within SSR coverage it makes your aircraft visible via TIS-B to properly equipped aircraft (that confusingly need to have ADS-B In *and* Out...remember by complexity comment about ADS-B earlier).

PowerFLARM (with the ADS-B In option, which almost all the units in the USA have) *does* receive ADS-B 1090ES and provide much of the same capabilities as a PowerFLARM-PowerFLARM system. Unfortunately it only receivers 1090ES and not UAT, and not ADS-R or TIS-B services, even if your glider has ADS-B Out to make it a ADS-R or TIS-B Client.... unfortunate European legacy there for where the ADS-B technology in PowerFLARM came from-hopefully FLARM will address in future. But even if all that worked... you can't properly receive ADS-R or TIS-B services unless you have a TABS or 2020 Compliant ADS-B Out system. (See comment earlier about complexity...)

For 2020 Compliant ADS-B Out in a certified glider today you are looking at: Trig TT22 (~$1,900) and TN70 (~$1,900) plus install costs.

For 2020 Complaint ADS-B Out in an experimental glider today you are looking at: Trig TT22 (~$1,900) and TN72 (~$350)

You can also use the TT22 and TN72 and do TABS in the type certified glider, that gets you visibility to other ADS-B in traffic and TIS-B and ADS-R client status, but not visibility to over ADS-B out to ATC and no post-January 1 2020 ADS-B Out airspace privileges. And that's ADS-B out only... can be a great thing for visibility to say GA traffic that increasingly has ADS-B In but not say TCAS the airliners and fast jets have. But to do fully featured Dual-link ADS-B In in a glider today you need a Stratus or Stratux box and a suitable display like Foreflight (my favorite...) today there is no way to integrate that with other glider flight displays... and by then you really risk having too much junk in the cockpit distracting the pilot. There is just no single perfect collision avoidance/awareness system for gliders in the USA. On the other hand we don't need to see more fatal mid-air collisions involving gliders... so we have to do the best we can and pick the technology or combination that works best. Perfect is the enemy of good..... doing nothing because we don't have a perfect systems avaialble is not a good option.

ADS-B has benefits in dense GA environments but it's the most complex and expensive to install. The starting point for glider pilots concerned about airliners, fast jets and military traffic is to equip with a transponder (Mode C is fine). Please talk to the military folks to see what their aircraft are equipped with and if they or ATC can see transponder and how much it will help. For folks mostly concerned about other gliders and towplanes the answer is PowerFLARM but you need multiple community adoption in the local area.

If both "fast jets, airliners, military" and "gliders and tow planes" are concerns then it unfortunately takes both a transponder and PowerFLARM. But it's worth remembering those are usually the first choices, not ADS-B Out and/or In.

The leading edge of ADS-B Out adoption in gliders are folks who already own a suitable Trig transponder and who can install a TN72 GPS Source at relatively low additional cost, and/or who have post January 1 2020 regulatory concerns such as needing to fly in Class A airspace or above Class B/C airspace but below 10,000' and so who will require 2020 Compliant ADS-B Out equipped gliders. Folks who do own a Trig transponder probably should consider adding at least a TN72 at their next annual.

And while Mode C is fine to keep using, any new transponder today should be a Trig TT22 as it provides most ADS-B Out options, and if installing now I'd also install the ~$350 TN72 GPS for 2020 Complaint ADS-B Out in an experimental glider or TABS in a type certified glider... that adds ADS-B Out benefits for a relatively small increase in cost... and while wiring up the transponder you might as well install the TN72.

BTW PowerFLARM (with the ADS-B option) also includes a PCAS capability, so the same PCAS capability as in your ATD-300 for transponder equipped threat aircraft with no 1090ES Out... if the threat has 1090ES Out you get a precise target.

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And yes all this is the technology side of stuff, yes folks need their head outside the cockpit, and it's my experience that pilots who are safety conscious enough to equip with this stuff are already pretty concerned about traffic and careful about looking outside, and PowerFLARM (and PCAS like your ATD-300) are good at reminding them to do that. And lots of other things can be done to understand traffic risks, develop ops and ATC procedures to try to reduce risks, etc.