Flarm suppression of ADS-B out on Tow Planes

On 3/19/19 4:50 PM, wrote:
On Tuesday, March 19, 2019 at 4:54:40 PM UTC-4, wrote:
For those towing behind tow planes equipped with ADS-B out (1090MHz), a new version of PowerFlarm firmware 6.67 is now available which should suppress the collision warning from the tow plane's ADS-B out. Below are release notes.


What about those tow planes equipped with ADS-B out using UAT (978MHz)?


PF doesn't receive 978 MHz, so there shouldn't be alarms generated.

On Tuesday, March 19, 2019 at 4:05:58 PM UTC-7, kinsell wrote:
On 3/19/19 4:50 PM, wrote:
On Tuesday, March 19, 2019 at 4:54:40 PM UTC-4, wrote:
For those towing behind tow planes equipped with ADS-B out (1090MHz), a new version of PowerFlarm firmware 6.67 is now available which should suppress the collision warning from the tow plane's ADS-B out. Below are release notes.


What about those tow planes equipped with ADS-B out using UAT (978MHz)?


PF doesn't receive 978 MHz, so there shouldn't be alarms generated.

Jeez is there anybody who has not been paying attention who actually has equipped a tow plane with UAT Out?

On Tuesday, March 19, 2019 at 7:18:33 PM UTC-4, Darryl Ramm wrote:
On Tuesday, March 19, 2019 at 4:05:58 PM UTC-7, kinsell wrote:
On 3/19/19 4:50 PM, wrote:
On Tuesday, March 19, 2019 at 4:54:40 PM UTC-4, wrote:
For those towing behind tow planes equipped with ADS-B out (1090MHz), a new version of PowerFlarm firmware 6.67 is now available which should suppress the collision warning from the tow plane's ADS-B out. Below are release notes.


What about those tow planes equipped with ADS-B out using UAT (978MHz)?


PF doesn't receive 978 MHz, so there shouldn't be alarms generated.

Jeez is there anybody who has not been paying attention who actually has equipped a tow plane with UAT Out?

skyBeacon is a pretty darn inexpensive and easy to implement way to make a tow plane 2020 compliant. I wouldn't be surprised if a significant number of people don't go that route, even though it is UAT instead of 1090ES.

A big question is exactly how FLARM has suppressed the tow plane ADS-B alarms. Does FLARM recognize the fact that the tow plane and glider are in formation, and only suppress the alarm while the formation flight continues, or does it somehow completely suppress all alarms for the tow plane? You definitely would want to see tow plane alarms after the glider releases from the tow in the event that you accidentally get on a collision course with the tow plane after the completion of the tow.

These seem to me to be two examples of difficulty assessing the number of decimal places in looking at probabilities.

Equipping a towplane with UAT says an owner is willing to spend money on ADS-B, but not the flavor that represents the vast majority of collision threats (it's a glider towplane after all). That just seems dopey. UAT is problematic for other reasons too in that it requires ADS-R or a dual-band receiver to be seen by the vast majority of aircraft that have opted for 1090ES and towplanes tend to operate down low where ADS-R services may not be available for other powered traffic. A waste of money that simultaneously makes other people's lives less safe and more difficult. Buying something that's far less likely to work because it's cheap hardly seems like a smart buy.

I doubt that Flarm would pick an algorithm that can both identify what's a towplane through formation flight and then blank out the ADS-B ICAO address and never check for towplane behavior again - but even if it did the probability of a towplane releasing a glider and circling around in a climb to become a collision threat seems like and extremely low probability scenario and not a reason to reject/critique the idea of towplane suppression. In 46 years of glider flying I've never, ever seen a towplane do that. Either way towplane suppression is a good idea and I tend to think the Flarm folks are pretty clever. I look forward to trying it out.

Andy Blackburn


On Tuesday, March 19, 2019 at 8:44:42 PM UTC-5, Mike Schumann wrote:
skyBeacon is a pretty darn inexpensive and easy to implement way to make a tow plane 2020 compliant. I wouldn't be surprised if a significant number of people don't go that route, even though it is UAT instead of 1090ES.

A big question is exactly how FLARM has suppressed the tow plane ADS-B alarms. Does FLARM recognize the fact that the tow plane and glider are in formation, and only suppress the alarm while the formation flight continues, or does it somehow completely suppress all alarms for the tow plane? You definitely would want to see tow plane alarms after the glider releases from the tow in the event that you accidentally get on a collision course with the tow plane after the completion of the tow.

Andy, I know of two mid airs between a tow plane and the glider it just released. One luckily just exchanged some paint, the other was fatal to both pilots. So I would hope and expect the suppression is only during the tow.

Ramy

On Tuesday, March 19, 2019 at 10:59:46 PM UTC-5, Ramy wrote:
Andy, I know of two mid airs between a tow plane and the glider it just released. One luckily just exchanged some paint, the other was fatal to both pilots. So I would hope and expect the suppression is only during the tow.

Ramy

If the fatal is the one I'm thinking of wasn't that on turn to final on a wave day? I'm thinking that would be long enough to reset even the most poorly designed algorithm. It's not like they're going to make a list of ICAO addresses that never ever get to be targets again. On the other hand, I could imagine some algorithms that might not alarm if you overrun the towplane while on tow or dive at the towplane immediately after release and never get much farther away than 200'. OTOH, maybe they handle that too. If they don't I'm fine and thankful for the quiet. I can keep an eye on the plane right in front of me.

We'll just have to see. Hopefully the algorithm mechanism and criteria for detecting an aircraft as towing you and the mechanism for removing them from 'your towplane' status will be in the release notes. The Flarm guys are clever so I bet they have thought through most scenarios.

Andy

On Tuesday, March 19, 2019 at 6:44:42 PM UTC-7, Mike Schumann wrote:


skyBeacon is a pretty darn inexpensive and easy to implement way to make a tow plane 2020 compliant. I wouldn't be surprised if a significant number of people don't go that route, even though it is UAT instead of 1090ES.


That would be the stupidest thing in the world. "significant number".... bull****. There are very few towplanes anywhere that I know of that are planning to equip with ADS-B Out for 2020 compliance reasons. I'm not aware of any of them going UAT, I had one question asked months ago and that person went away understanding why to use 1090ES Out not UAT. I only hear about ADS-B Out installs that folks ask for help with, but by now I'd hope that enough people know to keep UAT away from PowerFLARM equipped gliders.

Must be a lot of stupid pilots! uAvionix is backed up close to a month on skyBeacon orders.....

.... around gliders. You have been here on r.a.s enough that if you do not understand the issues and context by now you never will.

On Tuesday, March 19, 2019 at 11:46:10 PM UTC-4, Darryl Ramm wrote:
On Tuesday, March 19, 2019 at 6:44:42 PM UTC-7, Mike Schumann wrote:


skyBeacon is a pretty darn inexpensive and easy to implement way to make a tow plane 2020 compliant. I wouldn't be surprised if a significant number of people don't go that route, even though it is UAT instead of 1090ES.


That would be the stupidest thing in the world. "significant number".... bull****. There are very few towplanes anywhere that I know of that are planning to equip with ADS-B Out for 2020 compliance reasons. I'm not aware of any of them going UAT, I had one question asked months ago and that person went away understanding why to use 1090ES Out not UAT. I only hear about ADS-B Out installs that folks ask for help with, but by now I'd hope that enough people know to keep UAT away from PowerFLARM equipped gliders.

The stupidest thing in the world is that PowerFlarm doesn't support ADS-R or TIS-B. The fact of the matter is that UAT exists in the US and a significant number of GA aircraft are going to use this technology whether or not they are tow planes. We have 30+ gliders operating out of Stanton MN, within the MSP Mode C veil. At least half of the mid-air threats are not gliders, but other GA aircraft operating in our airspace. Not only do gliders need to be visible to this traffic, but they should also be equipped with real, US standards compliant ADS-B IN receivers (preferably dual frequency) so they can see all of the non-glider traffic in the area.