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Old March 22nd 18, 09:04 PM posted to rec.aviation.soaring
Darryl Ramm
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Default Flarm collision alert from Tow Plane ADS-B

On Thursday, March 22, 2018 at 11:19:28 AM UTC-7, Mike Schumann wrote:
On Thursday, March 22, 2018 at 12:19:04 PM UTC-5, wrote:
I have received the following from Flarm Technology and LXNav:

Flarm Technology response:

"This makes it really hard to deal with the situation nicely. Consider that you do want to have alarms from tow planes in some situations, but not in the tow. FLARM handles this correctly by sending meta-information on the aircraft (tow plane vs. glider). This data is unfortunately not present on ADS-B.

Really the only advice I can offer to install a FLARM on the tow plane (can be cheap, may not need a display etc.)"

Good new on gliders with Flarm and ADS-B out:

"If the aircraft type and addresses are correctly configured, then the alarm should be suppressed (FLARM signals get precedence in calculating threats over ADS-B)."

LXNav response:

"Sxxx vario or any flarm display are displaying collision warnings, which are transmitted from flarm. Flarm device is the "smart one" in this case, and decides, when warinign is necessary and what will be the level of that warning."

"Because a lot of pilots sometimes don't want to be annoyed with flarm warnings, we mace "cancel or dismiss" button. That is lower rotary knob, which has dismiss function, if flarm warning is appeared on Sxxx vario. With pushing that button, you will dismiss rarnings for YY seconds. You can set that value in the bottom of setup-warnings-flarm menu.
After first warning, you will press lower knob, and you will not get any more warnings for so many seconds as you have set in the setup."

"Dismissing warning has nothing to do with level of flarm warning."

"If you want to cancel them for 5 minutes, just det dismiss time to 300seconds."

I'll give the above a try on my next flight.


This is just another example of the half baked implementation of ADS-B in PowerFlarm.

Granted, ADS-B does not transmit velocity vectors like FLARM does, but that does not prevent the ADS-B receivers from tracking ADS-B targets and computing the vector information on the receiver side. All of the regular ADS-B receivers on the market in the US do this in order to intelligently predict traffic warnings only when a collision threat is real.

The other problem with PowerFlarm is that they have not implemented a UAT receiver or TIS-B or ADS-R support. As a result, you don't see any UAT equipped aircraft, nor do you get an accurate position report from transponder equipped aircraft that don't have ADS-B OUT systems.


Oh hell it's UAT boy again. Nice tights and cape....

The issue here that FLARM is pointing out is that their system does not know the aircraft is a towplane, not calculating the aircraft vector. A wonderful test for the problem situation would be to put a PowerFLARM portable in the towplane and see what happens.

No ADS-B receiver gets close to being usable like FLARM is on close glider-glider situations, so I have no idea what you are talking about. And I am pretty sure you don't either.

And in the meantime that imperfect FLARM technology is helping make things safer for many glider pilots in the USA and elsewhere. If we kept listening to the uniformed rambling from you we'd likely had more dead glider pilots.. The good news is that with your ramblings over the years I hope that everybody reading r.a.s. has worked out you have no clue what you are talking about.

And TIS-B and ADS-R support, yes its an issue to be aware of if pilots have ADS-B Out. And that is just staring to happen. And FLARM is well aware of that and looking at possible options for adding that support (so not a hard promise, but they are well aware of it), as I've explained before on r.a.s..