On Saturday, January 2, 2016 at 12:33:41 PM UTC-8, Greg Delp wrote:
What if the NPRM that came out this past summer goes through and gets rid of the glider exceptions to transponder and thus ADS-B mandates? Almost all contests in the west that get above 10,000' will now have gliders that must be equipped with transponders and ADS-B out compliant with the FAA's TSO specifications. This will also be true for some areas in the east where glider transponder exceptions are currently used. How will FLARM be able to filter out ADS-B reported gliders while using stealth/competition mode and not other ADS-B traffic? This will require another completely new FLARM system to be able to transmit and filter ADS-B out signals. Is the RC going to be able to force FLARM or anyone else to design and build a device that will be compliant with all of the FAA mandates transponder and ADS-B out in addition to the FLARM functions we need for the types of operation gliders typically perform? Or are we going to paint ourselves in a corner waiting to fly a contest while hoping for that future device. ADS-B out for us is coming soon whether we like it or not. I for one think out and in is a good thing for everyone who shares our skies.

I agree with the high level point/concern, but lets be careful on details here. Transponder and ADS-B carriage mandates are entirely separate regulations, getting rid of the transponder exemptions does not necessarily mean the ASD-B Out carriage exemption would go as well. But if anything I personally expect both to exemptions will be removed, and hope that at least TABS device carriage will be able to effectively met both requirements in modified regulations.

FLARM does not transmit ADS-B Out. And the chance of FLARM doing a ADS-B Out device I would say are zero--they don't play in the expensive to develop for and already crowded regulated avionics market. Anything the FAA mandates for transponder or ADS-B *Out* carriage is really orthogonal to FLARM products, except that (the appropriate model) PowerFLARM can receive 1090ES In direct

Nobody will get to "filter ADS-B Out signals, if your aircraft is mandated to require ADS-B Out you transmit the position and other data once ~every second. Even if not mandated and you want to do something differently I'll be happy to provide a personal introduction to an FAA employee.

But as I've pointed out here before. ADS-B Out or TABS requirements for gliders (e.g. if required above 10,000') and especially with a likely "if equipped must use" regulation may make all the FLARM technology-angst irrelevant. What would the RC do? Require all PowerFLARM ADS-B In (and PCAS?) to be entirely disabled? (ah no from a safety and liability viewpoint). Work with FLARM to obfuscate PowerFLARM ADS-B In data? For glider types only... So faster aircraft are still seen at a larger distance? Oops just impossible to do that at range where you see the ADS-B before the FLARM signal from a glider. So you are kinda screwed there. Do you rely on the ADS-B airframe information to be accurate and obfuscate gliders based on that? On a black list of ICAO addresses of contest gliders? Oh my head hurts, what problem are we trying to solve again?

But then what do you do? Ban any other ADS-B receiver? Including tiny USB stick for a PDA or similar? What about a pilot who wanted to receive TIS-B or ADS-R input to warn of GA aircraft? Seems a valid safety thing for them to expect to be able to do that and not be told they cannot... that creates an interesting liability situation. Do you cavity search pilots before a contest for USB stick receivers? Search gliders for hidden bluetooth receivers that can drive a PDA or iPhone etc? I am sympathetic to some of the concerns of folks but chances of putting the technology genie back in the bottle ah seem slim....