FLARM in USA?

[Jeff Bures]

I gather that FLARM is much more popular outside of the USA. Are most well equipped sailplanes installing FLARM in the USA? What about other GA aircraft in the USA?

Is FLARM more common (or a necessity) at competitions in the USA? For club and casual cross-country soaring, it might be less prominent.

Having both FLARM in/out and ADS-B in/out is getting quite expensive. Would a budget minded sailplane in the USA get FLARM or ADS-B. Which has the most utility for situational awareness and safety in the USA?

What does FLARM offer that ADS-B does not? I'm assuming FLARM is faster and more accurate for gaggles. What's the relative refresh for FLARM and ADS-B data?

Yes, I know ADS-B out would open up some airspace that would normally be excluded, but I'm ignoring that factor for now.

[son_of_flubber]

Power Flarm is used in the USA, and people often shorten this to Flarm, but it is different than the Flarm used in the rest of the world.

ADS-B is useless in gaggles beyond telling you that there another glider in the gaggle. Power Flarm is useful in gaggles because it filters spurious proximity warnings.

ASB-out makes me visible to power pilots who're looking at their screens. I was once thermalling and overheard Flight Following warn a power pilot that I was on his 12 at same altitude, two mile. He continue to close, one mile. He finally said, 'I still don't see the glider, but I have him on ADS-B, diverting."

[Mike Schumann[_2_]]

On Thursday, February 18, 2021 at 6:04:47 PM UTC-6, Jeff Bures wrote:
> I gather that FLARM is much more popular outside of the USA. Are most well equipped sailplanes installing FLARM in the USA? What about other GA aircraft in the USA?
>
> Is FLARM more common (or a necessity) at competitions in the USA? For club and casual cross-country soaring, it might be less prominent.
>
> Having both FLARM in/out and ADS-B in/out is getting quite expensive. Would a budget minded sailplane in the USA get FLARM or ADS-B. Which has the most utility for situational awareness and safety in the USA?
>
> What does FLARM offer that ADS-B does not? I'm assuming FLARM is faster and more accurate for gaggles. What's the relative refresh for FLARM and ADS-B data?
>
> Yes, I know ADS-B out would open up some airspace that would normally be excluded, but I'm ignoring that factor for now.
There are virtually no GA aircraft in the US equipped with FLARM. Both FLARM and ADS-B have a refresh rate of 1 second. The accuracy of the position transmissions for both FLARM and ADS-B are virtually identical, as both are limited by the accuracy of GPS signals received by the aircraft.

The difference between the two systems is primarily in the collision avoidance algorithms implemented by the systems. FLARM is focused on dealing with gliders which can fly in relatively close quarters. ADS-B receivers themselves do not generally incorporate collision avoidance algorithms. Instead they just pass along traffic information to whichever display devices they connect to. Various display devices and/or apps have collision warning algorithms of varying sophistication. While most ADS-B systems are focused on providing situational awareness to pilots so they can see and be warned of other traffic in their vicinity, the goal is usually to give other aircraft a relatively wide birth, not to coordinating flying at close quarters.

Technically, there is nothing preventing the development of an ADS-B receiver with as sophisticated a collision avoidance algorithm as FLARM, but given the relatively small size of the glider market in the US, it does not appear that there is any significant effort to develop that kind of system.

[Jeff Bures]

On Thursday, February 18, 2021 at 6:59:58 PM UTC-8, Mike Schumann wrote:
> On Thursday, February 18, 2021 at 6:04:47 PM UTC-6, Jeff Bures wrote:
> > I gather that FLARM is much more popular outside of the USA. Are most well equipped sailplanes installing FLARM in the USA? What about other GA aircraft in the USA?
> >
> > Is FLARM more common (or a necessity) at competitions in the USA? For club and casual cross-country soaring, it might be less prominent.
> >
> > Having both FLARM in/out and ADS-B in/out is getting quite expensive. Would a budget minded sailplane in the USA get FLARM or ADS-B. Which has the most utility for situational awareness and safety in the USA?
> >
> > What does FLARM offer that ADS-B does not? I'm assuming FLARM is faster and more accurate for gaggles. What's the relative refresh for FLARM and ADS-B data?
> >
> > Yes, I know ADS-B out would open up some airspace that would normally be excluded, but I'm ignoring that factor for now.
> There are virtually no GA aircraft in the US equipped with FLARM. Both FLARM and ADS-B have a refresh rate of 1 second. The accuracy of the position transmissions for both FLARM and ADS-B are virtually identical, as both are limited by the accuracy of GPS signals received by the aircraft.
>
> The difference between the two systems is primarily in the collision avoidance algorithms implemented by the systems. FLARM is focused on dealing with gliders which can fly in relatively close quarters. ADS-B receivers themselves do not generally incorporate collision avoidance algorithms. Instead they just pass along traffic information to whichever display devices they connect to. Various display devices and/or apps have collision warning algorithms of varying sophistication. While most ADS-B systems are focused on providing situational awareness to pilots so they can see and be warned of other traffic in their vicinity, the goal is usually to give other aircraft a relatively wide birth, not to coordinating flying at close quarters.
>
> Technically, there is nothing preventing the development of an ADS-B receiver with as sophisticated a collision avoidance algorithm as FLARM, but given the relatively small size of the glider market in the US, it does not appear that there is any significant effort to develop that kind of system.

Thanks for the great info. It helped!

[Andy Blackburn[_3_]]

Most well-equipped gliders in the US have PowerFLARM and at least a Mode-S transponder, such as a Trig TT22. An increasing proportion are equipping with ADS-B Out since the incremental cost is relatively low to add a GPS source. PowerFLARM is a 1090ES ADS-B In device and now decodes TIS-B (rebroadcast SSR targets) and ADS-R (rebroadcast UAT targets). Proper coverage for rebroadcast targets really requires ADS-B Out to establish the service "puck" around your aircraft for these rebroadcast targets from ADS-B ground infrastructure.

I am not aware of any gliders that have ADS-B Out but not FLARM. There may be a handful. There are many with FLARM but not ADS-B Out, though most of those have a transponder in my experience. I fly out west where transponders seem quite prevalent.

If you are flying a glider out of an area with other gliders in the vicinity it is likely that your biggest threat will be another glider. A FLARM-compatible collision avoidance device is required at all US National Championships and may be required by individual event organizers at regional contests or cross-country camps.

Andy Blackburn
9B

On Thursday, February 18, 2021 at 4:04:47 PM UTC-8, Jeff Bures wrote:
> I gather that FLARM is much more popular outside of the USA. Are most well equipped sailplanes installing FLARM in the USA? What about other GA aircraft in the USA?
>
> Is FLARM more common (or a necessity) at competitions in the USA? For club and casual cross-country soaring, it might be less prominent.
>
> Having both FLARM in/out and ADS-B in/out is getting quite expensive. Would a budget minded sailplane in the USA get FLARM or ADS-B. Which has the most utility for situational awareness and safety in the USA?
>
> What does FLARM offer that ADS-B does not? I'm assuming FLARM is faster and more accurate for gaggles. What's the relative refresh for FLARM and ADS-B data?
>
> Yes, I know ADS-B out would open up some airspace that would normally be excluded, but I'm ignoring that factor for now.

[Dan Marotta]

Not so if your glider is certificated in the Standard Airworthiness
category. If so, then you must use a TSO approved position source which
costs considerably more.

Dan
5J

On 2/19/21 1:28 AM, Andy Blackburn wrote:
> An increasing proportion are equipping with ADS-B Out since the incremental cost is relatively low to add a GPS source.

[Richard Pfiffner[_2_]]

Jeff,

Just to be clear Powerflarm offers collisions warning in both Flarm & ADSB

Transponder and ADS-B Receiver
While many aircraft are already FLARM-equipped, there are still some that are not. With the transponder and ADS-B 1090ES receiver, you are protected from many of those aircraft as well. The additional receiver listens for intruders transmitting Mode-S and ADS-B messages on 1090 MHz and includes those aircraft in the smart trajectory prediction and collision warning algorithms. Since aircraft without FLARM cannot see you, it is all the more important that you can see them early to keep a safe distance.

Richard
www.craggyaero.com


On Thursday, February 18, 2021 at 9:08:50 PM UTC-8, Jeff Bures wrote:
> On Thursday, February 18, 2021 at 6:59:58 PM UTC-8, Mike Schumann wrote:
> > On Thursday, February 18, 2021 at 6:04:47 PM UTC-6, Jeff Bures wrote:
> > > I gather that FLARM is much more popular outside of the USA. Are most well equipped sailplanes installing FLARM in the USA? What about other GA aircraft in the USA?
> > >
> > > Is FLARM more common (or a necessity) at competitions in the USA? For club and casual cross-country soaring, it might be less prominent.
> > >
> > > Having both FLARM in/out and ADS-B in/out is getting quite expensive. Would a budget minded sailplane in the USA get FLARM or ADS-B. Which has the most utility for situational awareness and safety in the USA?
> > >
> > > What does FLARM offer that ADS-B does not? I'm assuming FLARM is faster and more accurate for gaggles. What's the relative refresh for FLARM and ADS-B data?
> > >
> > > Yes, I know ADS-B out would open up some airspace that would normally be excluded, but I'm ignoring that factor for now.
> > There are virtually no GA aircraft in the US equipped with FLARM. Both FLARM and ADS-B have a refresh rate of 1 second. The accuracy of the position transmissions for both FLARM and ADS-B are virtually identical, as both are limited by the accuracy of GPS signals received by the aircraft.
> >
> > The difference between the two systems is primarily in the collision avoidance algorithms implemented by the systems. FLARM is focused on dealing with gliders which can fly in relatively close quarters. ADS-B receivers themselves do not generally incorporate collision avoidance algorithms. Instead they just pass along traffic information to whichever display devices they connect to. Various display devices and/or apps have collision warning algorithms of varying sophistication. While most ADS-B systems are focused on providing situational awareness to pilots so they can see and be warned of other traffic in their vicinity, the goal is usually to give other aircraft a relatively wide birth, not to coordinating flying at close quarters.
> >
> > Technically, there is nothing preventing the development of an ADS-B receiver with as sophisticated a collision avoidance algorithm as FLARM, but given the relatively small size of the glider market in the US, it does not appear that there is any significant effort to develop that kind of system..
> Thanks for the great info. It helped!

[son_of_flubber]

Note that Power Flarm also has some ADS-B-in capabilities.

[Jeff Bures]

On Friday, February 19, 2021 at 9:38:41 AM UTC-8, son_of_flubber wrote:
> Note that Power Flarm also has some ADS-B-in capabilities.

Does the PowerFlarm ADS-B in also support weather?

[Jeff Bures]

On Friday, February 19, 2021 at 9:49:19 AM UTC-8, Jeff Bures wrote:
> On Friday, February 19, 2021 at 9:38:41 AM UTC-8, son_of_flubber wrote:
> > Note that Power Flarm also has some ADS-B-in capabilities.
> Does the PowerFlarm ADS-B in also support weather?

Going from nothing to a decent PowerFlarm Fusion + Transponder w/ADS-B out is somewhere around $6k. That's a tough nut to swallow for a mid-range sailplane.

[kinsell]

On 2/19/21 10:49 AM, Jeff Bures wrote:
> On Friday, February 19, 2021 at 9:38:41 AM UTC-8, son_of_flubber wrote:
>> Note that Power Flarm also has some ADS-B-in capabilities.
>
> Does the PowerFlarm ADS-B in also support weather?
>

No, it's traffic only, it's 1090 MHz only, and it's possible to buy a PF
device without even that.

If they ever added a UAT receiver, I'd upgrade from my Core, but that's
U.S. proprietary, so not likely to ever happen. Real pity, since it's
$10 worth of hardware. The retransmit of ADS-B signals is a non-starter
for me.

Generally best to fly with a PF, add a ADS-B receiver if you want to
receive both transponder frequencies and wx.

PF is extremely low power, ADS-B is massive overkill for aircraft to
aircraft collision avoidance, but ATC likes to see you 200 miles away.

Dave