edwalker Posted November 12, 2016 Report Share Posted November 12, 2016 I have a Dynon SV with ADSB and LXNAV S7 (former V7) variometer. Last year I installed a Powerflarm Core and I've been having some issues with nuisance PCAS alerts. This manifests as repeated (sometimes as often as every 5 sec) PCAS targets 0.2 - 0.4 nm distance with nothing in sight. At first I thought it was just antenna issues, but having done a good bit of experimentation over the last year I've concluded that this is some sort of XPDR/Powerflarm interaction problem. I ran an ADSB compliance report and to my surprise learned that the XPDR, despite being configured as emitter category GLIDER is showing up as PARACHUTIST/SKYDIVER on the report. I ran this by Dynon, and they confirmed that their relabeled Trig TT-22 is indeed not putting out the correct category when set to GLIDER in the setup. The Powerflarm installation manual seems to make a big deal about the emitter category being correctly set to GLIDER, so I'm working with Dynon to figure out a workaround. Have any of you run your ADSB compliance report? If so, could you check for me whether your emitter category comes out the way it is supposed to? The transponder setup menu is on the first page of the SV setup screen, and it has an emitter category section. If you're out at the hangar and you've already run your ADSB compliance report please let me know if the categories match so I can give more data to Dynon. They seem to think that this is a Trig firmware issue and they are researching it. Not sure it will have any consequences other than Powerflarm function. By the way, does anyone else have a PF Core installed? Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted November 12, 2016 Report Share Posted November 12, 2016 I actually ran into the same issue with the ADS-B compliance report that you did and contacted both Dynon and the FAA. Dynon told me that they were putting out the correct signal and that the problem was with the FAA. About a month ago, I ran another ADS-B compliance report, and it now showed correctly that I was a glider. When was the last time you ran the compliance report? Quote Link to comment Share on other sites More sharing options...
edwalker Posted November 12, 2016 Author Report Share Posted November 12, 2016 Thanks, Mike. I ran the report yesterday. I uploaded a diagnostic file Tuesday and that's when Dynon stated that they could see that the transponder was not set correctly. They are looking into this on Monday, so I should know soon. Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted November 12, 2016 Report Share Posted November 12, 2016 I flew today and just downloaded an ADS-B performance report. You are right. It's still wrong. I sent both Dynon and the FAA an e-mail with a copy of the report. Note: I'm running the latest Dynon firmware. Let us know if you hear anything. Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted November 14, 2016 Report Share Posted November 14, 2016 I just got an e-mail from the FAA. It's definitely a Dynon problem. I'm transmitting emitter type 11. The correct emitter type for a glider is 9. I have forwarded the e-mail to Dynon. Hopefully they will fix this soon. It's interesting that my flights are not showing up in the FlightRadar24 database. I am wondering if this is related to the emitter type problem. Quote Link to comment Share on other sites More sharing options...
edwalker Posted November 14, 2016 Author Report Share Posted November 14, 2016 Mike, I expect that this defect will be found in all the Phoenix motorgliders with Dynon SkyView installations if they are configured as "glider" in the transponder setup menu. I sent an email to Dynon this morning asking them to please get this fixed because it's one thing if it's just a mistake in sorting us as traffic, but if my hunch is correct about Powerflarm using emitter category in its data filtering algorithm, it may also be interfering with Powerflarm anti-collision algorithms. I made them aware of that as a potential safety issue, not just an FAA aircraft sorting bug. Apparently someone brought this up earlier, perhaps it was you, and they at first recommended just treating motorgliders as LIGHT aircraft (category 1, I believe) since we flew that way. Hopefully this has escalated the issue a bit. They agree that the Trig output is incorrect - the issue is whether SV is passing a bad parameter or the Trig has a firmware fault that puts out the wrong category code. Thanks for helping me figure this out. Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted November 14, 2016 Report Share Posted November 14, 2016 Not only is this affecting the FAA, but sending out the wrong emitter code is apparently preventing my flights from showing up in the FlightRadar24 database. I just got an e-mail from Dynon claiming that this is an FAA problem. I sent them a copy of the email I got from the FAA this morning. Hopefully, they will get this resolved ASAP. Keep the pressure on..... Quote Link to comment Share on other sites More sharing options...
edwalker Posted November 14, 2016 Author Report Share Posted November 14, 2016 I just got a call from Dynon tech support. This is getting complicated. They ran a bench test on their R&D lab SV v15.2 and xpdr v2.09 and they cannot duplicate the problem! For a glider xpdr configuration they get a glider emitter category every time. They even examined the xpdr output at the bit level and it checks out. Their only possible conclusion was that it had to be at the FAA end in their ADSB software. I'm going to run a test for them later this week since they are just a few miles from where I live. One of the engineers has a small Raspberry Pi-driven xpdr receiver that can actually record xpdr output and then they can analyze it back at the shop. To be honest, Mike, I have to believe the Dynon engineers on this one since they are taking the time to take this seriously and they have the data to back their opinions. They actually ran the experiment, so I'm less inclined to believe the FAA at this point. If the Raspberry Pi data confirm Dynon's position on this then we have a bench test plus a real world application confirmation, and I'm going to write to the FAA and politely ask them to escalate this internally. By the way, the other interesting thing that may be related to my PCAS problem was that he told me was that the my transponder was rapidly switching between GND and ALT in the diagnostic file I sent him. Apparently, since SV is designed for aircraft and not gliders, the xpdr software has a configuration called Auto ALT/GND which is set to automatically switch from to GND and ALT based on a combination of airspeed and GPS data, and that happens around 50 kts. That's not helping us either. If the xpdr is switching off and on I may need to turn that auto function off and control the xpdr manually to make sense of all this. What a mess. To the other owners: I think we need to stay coordinated on this. Since Dynon has been dealing with Mike and me, please let us know before you send any comments into into their tech support. We have one engineer who is very familiar with and interested in this problem, and I have a good relationship with him. The others will just be starting from scratch if you contact support. Mike, can you send me a copy of the email you got from the FAA so I can follow up with that same person? My email is edwalker@uw.edu. My sense is that we need a light touch on this - I don't think Dynon is to blame, and it's going to be difficult to get the FAA interested in such a small subgroup of their clientele. Who knows if this is related to my repetitive PCAS problems, but at least we're making progress. After all, what else is there to do off season except work on obscure glider-related issues. At least I haven't thought about the election all day. Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted November 15, 2016 Report Share Posted November 15, 2016 I suspect that the Phoenix owners are on the absolute bleeding edge for ADS-B OUT for both Dynon and the FAA. Phoenix Motorgliders probably are by far the largest population of ADS-B OUT equipped gliders currently flying in the US. As a result, we are probably acting as unwitting beta testers for both Dynon and the FAA. I haven't been paying attention to the transponder gnd/alt status when I turn the motor off and start soaring. We should definitely talk to Dynon about fixing the transponder AUTO function if this is causing us to switch to gnd mode while in flight. If you have a chance can you find out what the exact algorithm is that Dynon uses for the AUTO function, so we can see if this is appropriate for gliders. Quote Link to comment Share on other sites More sharing options...
mikeschumann Posted February 7, 2018 Report Share Posted February 7, 2018 I got an e-mail from the FAA yesterday indicating that they finally fixed the ADS-B ground stations in my area, so that they now correctly recognize my Phoenix as a glider rather than a "Skydiver / Parachutist". I ran an ADS-B Performance report on my last flight from Naples FL to Sebring in late January, and sure enough, it now shows that I am a glider. It would be interesting to see if this fix has rolled out nation wide yet. Quote Link to comment Share on other sites More sharing options...
edwalker Posted April 17, 2018 Author Report Share Posted April 17, 2018 Yes, this appears to be finally working properly. Eric and I both now have appropriate Glider emitter category on our ADS-B performance reports as of this month. I did not get an email, but I assume this was a national fix. Has anybody else checked? Ed Quote Link to comment Share on other sites More sharing options...
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