Is FLARM helpful?

[Casey Cox]

Has anyone been thankful that they have had FLARM?

And do the same people have a transponder?

How many people fly with FLARM or Transponder?

Let's hear about the close calls, or potential close calls, or even the peace of mind of awareness.

[Jonathan St. Cloud]

I have a Flarm and a transponder. A am of the opinion that you owe it to the pilots you fly with to have a Flarm, makes it much safer for you and the pilots you share the same airspace. i know in France, maybe other European countries Flarm is mandatory, and for a good reason. As for transponder, I fly where there is much traffic and again, it is much safer with the mode S transponder, I can see the fast jets before I could visually.

[JS]

Flown with FLARM in quite a few gliders during the last 8-9 years. Can only credit one warning with possibly preventing a collision. Certainly it saw the head-on traffic at 12:00 same altitude before I did.
How many of those situations is enough to validate its use? I believe one.
Jim
TXP? Yes.

[chip.b...@gmail.com]

In terms of actual incidents, not opinions, I've only flown with FLARM since July. I've gotten several increasingly shrill warnings before I saw the gliders. All were in my blind spot behind. I'm not ready to label those "close calls" because the other pilots may have seen me. But it certainly enhanced my awareness of potential dangers.

I'm generally skeptical of gadgets that purport to improve safety marginally at great cost (and cynical of the glib question: "isn't your life worth more than [fill in the blank with whatever pricetag]?"). But after borrowing a PowerFLARM for one contest this year, I bought one.

No transponder.

Chip Bearden
ASW 24 "JB"
U.S.A.

[John Godfrey (QT)]

You may want to review the SSA Competition Pilot Poll Results posted on the SSA website.

[Casey Cox]

>
> You may want to review the SSA Competition Pilot Poll Results posted on the SSA website.

I didn't realize FLARM was such a hot topic in the Poll, and having such varying opinions.

I think the concept is great, but I do not know enough about FLARM and ADS-B to really have much of a conversation about them.

Thanks for the comments above and the direction to the Poll.

[Tim Taylor]

If you fly with other gliders, especially cross-country FLARM is the way to go.

I have had several alerts at high altitude and high speeds that I would have never seen the other gliders in time without FLARM.

I flew US Nats in 2009, 2010, and 2011. Three mid-airs, one fatal. Since 2012 all nats have had mostly FLARM equipped gliders, no mid-airs. I would not race without FLARM now and all our local group uses FLARM.

TT

[Chris Davison]

At 01:35 21 November 2015, Casey Cox wrote:
>Has anyone been thankful that they have had FLARM?

yes!

https://www.youtube.com/watch?v=vPgSbRzAXnk

[cern...@gmail.com]

Well, I'm sure it's worth much more than its cost, even though the hardware is probably only worth 1/10 of the sale price. Other pilots have different opinions. In my case:
. it saved me or the other pilot at least three times; during all of these events, I noticed a glider, but failed to notice another lower/higher or on a different relative heading.
. since when I started using it, it usually informs me of another glider much sooner than my eyes could spot it.
. on one occasion, me and the other pilot escaped a collision with only a few meters distance, but the GPS in my Flarm didn't have a valid fix, so the device couldn't work. We both were aware of each other's presence, as we were flying together and chatting on the same frequency, we only lost eye contact for probably less than a minute.
. I feel much more in company and enjoy competitions much more, due to the awareness of the relative position of some of my fellows.

best,
aldo cernezzi
www.voloavela.it

[waremark]

I had a midair on conflicting thermal entry 12 years ago. We had been quite close for several minutes but the other guy did not know I was close to him. If we had both had Flarm then the crash would almost certainly not have happened. (Of course there should have been other ways to avoid it!)

[Jonathan St. Cloud]

Wondering if there are any statistics regarding Flarm use in the the U.S.? i know at the glider port I fly from most have Flarm, but I see many gliders for sale on Wings and Wheels do not have Flarm.

[srat...@xmission.com]

I have had a PowerFlarm Core for a year now and found it to be very helpful alerting me to gliders and other traffic. As others have already said, this alone justifies having one in your glider.

Another major benefit of having Flarm when flying with others with Flarm is that it really cuts down on the need for radio chatter as everyone can see where everyone is and how they are doing. Location and rate of climb/sink is displayed.

[jwgc20...@pages.plusgoogle.com]

It's a no brainer - why would you not want to be alerted to aircraft that you have not seen with your own eyes !

I've flown many competitions with multiple classes where the vast majority of gliders ( 1 or 2 exceptions ) have Flarm, it becomes disconcerting how many gliders I visually "miss" ... and I don't think my lookout is particularly bad.

I would make it compulsory for all Gliders and tugs in competitions.

I truely think the risk associated with another distracting instrument in the cockpit is far, far outweighed by the situational awareness it provides.

[Andy Blackburn]

On Sunday, November 22, 2015 at 3:59:15 PM UTC-8, Jonathan St. Cloud wrote:
> Wondering if there are any statistics regarding Flarm use in the the U.S.? i know at the glider port I fly from most have Flarm, but I see many gliders for sale on Wings and Wheels do not have Flarm.

You have to select the appropriate denominator when you look at "use". If you look as a percent of all FAA-registered gliders it will be pretty low - but lots of gliders on the registry are inoperative or even destroyed. If you assume a few thousand regularly flying gliders then the penetration is probably less than 30%. However, if you look at the most active gliders that represent most of the flight hours (and therefore collision threat) there are two broad groups - training and ride gliders and cross-country and racing gliders.

There have been a number of clubs and commercial operators (e.g. Soaring Club of Houston and Williams Soaring) that have equipped their entire fleets, but generally you'll see less here because of cost, lack of battery power and other reasons. They tend to spend a lot of time around the airport and in the pattern. The cross country and racing set have higher penetration - virtually all the high-hours OLC pilots on the west coast (due in part to extensive convergence and street flying at high altitudes and airspeeds) have adopted Flarm. Among racing pilots responding to this fall's poll 77% overall and 94% of pilots who flew in a Nationals have Flarm.

I'd wager that some of the gliders you are seeing for sale have not flown a lot and are being sold for that reason. I wouldn't take it as totally representative of the proportion of Flarm-equipped gliders you are likely to observe when you go flying, which is more based on hours in the air.

If you are just doing patterns and flying locally, collision avoidance will tend to be more "old-school" see-and-avoid, but it varies a lot with the local operation. If you intend to go cross country or fly in a contest it'll be a very different story. It's increasingly frowned upon to show up at a contest or OLC camp without one and some are now Flarm mandatory.

9B

[Casey Cox]

Ok. How long has Flarm been readily available/used, and is there anything starting to take its place that would make Flarm obsolete or not purchased as much in a couple of years?

[Richard]

On Monday, November 23, 2015 at 2:31:46 PM UTC-8, Casey Cox wrote:
> Ok. How long has Flarm been readily available/used, and is there anything starting to take its place that would make Flarm obsolete or not purchased as much in a couple of years?

I think I sold my first PowerFlarm in Spring 2011. I don't see anything in development to replace it or provide the collision avoidance features.

http://www.craggyaero.com/powerflarm.htm



Richard
www.craggyaero.com

[Andy Blackburn]

On Monday, November 23, 2015 at 2:31:46 PM UTC-8, Casey Cox wrote:

> Ok. How long has Flarm been readily available/used, and is there anything starting to take its place that would make Flarm obsolete or not purchased as much in a couple of years?

Here - read this. Should give you everything you need to know.

https://drive.google.com/drive/folders/0Bw1ChKkWEYLNNHJMU2ZyVy16QzQ

9B

[Sean Fidler]

FWIW, I have had at least 2 very close calls in which I would have been very, very close to a collision without FLARM. Equally important, I have had numerous FLARM warnings in which I was not aware of the glider nearby until the warning. These warnings (quite common) are invaluable and their situation awareess safety value is incalcuable.

The first close call was actually during the very first week that the flarm was released in the USA during the 2011 Uvulde glide. Two open class gliders flew right across my nose (45 degrees off head on). Less than 50 meters at the exact altitude. I saw the first at the last second (no flarm). I never would have seen the second glider (in trail of the first) without the flarm warning. Terrifying but I was able to get a visual on the second and dive below. We would have hit nose to nose without the dive. The collision was maybe 5 seocnds away. I was shaking for the next hour. Im not sure if they ever saw me.

From that moment on, I felt failry exposed flying without FLARM...and feel that gliders flying contrsts or busy enviornments without FLARM are failry dangerous. The other close call would have almost certainly been a head on collision in a pre-start situation. I am a "scan freak" and am always moving my head and my eyes, and try not to rely on FLARM at all as there are always at least a few non-flarm gliders in any group. Regardless of that flaw, FLARM warnings are almost always useful and highly acurate.

A good example of a FLARM warning is at the 9:10 point of this video: https://vimeo.com/52396659

So the short answer is yes, I am thankful of Flarm and thankful to the fellow pilots (and towpilots) who have invested in it.

7T

[bertvaneyken]

Even for gliders in the local pattern you should certainly consider buying a FLARM.
In our club we decided to install it in every aircraft, even the paraclub decided to install devices in their drop planes.

We had serveral very very close calls:
- The Cessna Grand caravan in short final aborted the approach because of the flarm beeping like crazy.
Our twin was just below in front of him in his blind spot. Luckily he didn't wait a blink of an eye longer.
- A tow pilot with glider on the rope not seeing another glider in the pattern, the instructor too busy with the student.
Only the flarm alerted them to make evasive manoevres.
- And a few others...

Flarm certainly saved our asses several times


Bert

[Ramy]

I think the reason that gliders for sale are not Flarm equipped is that their owners rather keep the Flarm and move it to their new ships, since once you fly with one you will never want to fly without it.

Ramy (With handful of Flarm saves in over 1000 hours with Flarm)

[Renny]

On Tuesday, November 24, 2015 at 5:26:50 AM UTC-7, Ramy wrote:
> I think the reason that gliders for sale are not Flarm equipped is that their owners rather keep the Flarm and move it to their new ships, since once you fly with one you will never want to fly without it.
>
> Ramy (With handful of Flarm saves in over 1000 hours with Flarm)

Agree 100% with Ramy. I had a portable PF in my Discus 2b, and when I sold it in early 2012, I kept the PF for my new LAK....As far as close calls, many of the folks that fly at Moriarty have had PowerFlarms since 2011 and I do believe it has been a major enhancement to safety. It has personally alerted me on several occasions over the past 5 seasons to gliders coming head on at high speed especially under cloudstreets. These alerts allowed me to alter my course and avoid any potential conflict. This past season we had an incident where two gliders came within 20-30 feet from each other and they never saw each other until the very last second. One glider had a PF and one did not....The pilot who did not have a PF went out and bought a PF immediately...

Finally, I do fly with a transponder and a PF as do many other folks at Moriarty. The use of transponders is also extremely important in our area as there is a fair amount of jet traffic passing over the area as they descend into Albuquerque. Albuquerque approach is very aware of gliders at Moriarty using 1202 on their transponders. When they "see" us they do try to route the airlines away from us and/or try to keep them above 18K as they pass west bound over the Moriarty area. Once past Moriarty they then allow them to descend into Albuquerque....This does really help minimize potential conflicts. Now, be safe out there! Thx - Renny

[James Metcalfe]

At 12:26 24 November 2015, Ramy wrote:
>... (With handful of Flarm saves in over 1000 hours with Flarm)

Interestingly, my experience is just the opposite: in 1593 hours in
the French Alps since 2007 (only 208 hours of which were without
Flarm), I have had no relevant alert from Flarm but hundreds of
false alarms. However I have experienced several dangerous or
very dangerous events (and many more daft ones) which can only
reasonably be ascribed to Flarm - or rather the false expectations
that some pilots seem to have of it.
The most stupid of these was two gliders simultaneously overtaking
me at speed from directly behind on a ridge, one each side, at
exactly my height, and with a horizontal separation of about a
wingspan. Fortunately, I had insisted that my pupil did *not* take
evasive action from the Flarm-announced threat, pointing out that
we might just turn into the path of the (imagined) single overtaker.
(I presume that the 2 overtakers thought "they know we're coming,
so they won't do anything stupid"!)
In the 2000+ hours in the Alps before Flarm I saw no such
dangerous behaviour; nor in the 208 hours 'gap' without Flarm in
2008.
Of course, nothing can be proved. But enthusiasts for Flarm should
be aware it has its down-sides.

[Richard]

Really James, I suspect something is very wrong with your Flarm.

I have approximately 1000 hours with PowerFlarm and have not experienced any issues with false alarms. 6 camps and contests with as many as 65 gliders.

Richard
www.craggyaero.com

[James Metcalfe]

At 18:03 24 November 2015, Richard wrote:
>... Really James, I suspect something is very wrong with your
Flarm. ...

Interesting thought. That would mean a fault in the Flarm
algorithms, or (highly improbable) a bad but operable installation of
the Flarm firmware. And, BTW, more than one Flarm unit was used
over those years.
J.

[Andy Blackburn]

Since you've owned several I guess it's safe to say there's more benefit than downside.

I'd be hard pressed to say I've ever had a false alarm - I guess it depends on how you define such a thing. If you mean an alarm when there were no other gliders in the air I would definitely look at whether you need to replace the hardware or firmware. If you mean you got an alarm for a glider in the area that you didn't think was an immediate threat you might consider 'competition mode' which sets the collision parameters tighter before issuing an alarm. We all have our comfort zone, but I'd be dubious about reports of alarms where that projected flight paths of the gliders involved weren't crossing within the radius of error that the algorithm assumes. As you may recall, Flarm projects curving flight paths, so you don't need to be on a straight-line converging path to generate an alarm. In a busy thermal you'll get lots of alarms, but the flying is so dynamic that the threats can come and go with regularity. It's not so much a false alarm in that case, but a transient conflict and probably not super-helpful, but technology has its limits in the analog world.

If the OP is considering whether to equip with Flarm I'd say if you intend to fly with other gliders, get one and if the other gliders don't all have them already, organize a group purchase.

I've had lots of useful alarms. I'd wager at least one prevented me from taking the silk elevator home.

9B

[Ramy]

One thing to point out is that James is likely referring to the European Flarm while most of us referring to Powerflarm which I understand is superior especially in the user interface side (butterfly display etc) and as such I believe better visually distinguishing between alerts and collision alarm.

Ramy

[Tango Whisky]

Am Dienstag, 24. November 2015 23:59:45 UTC+1 schrieb Ramy:
> One thing to point out is that James is likely referring to the European Flarm while most of us referring to Powerflarm which I understand is superior especially in the user interface side (butterfly display etc) and as such I believe better visually distinguishing between alerts and collision alarm.
>
> Ramy

I have about 1600 hours flying with the European Flarm in the French and Swiss Alps, and I have had more than one occasion where the Flarm warning solved a very hairy situation. I also have had many false alarms, but I can live with that - I'd always take a false positive over a false negative.
On the technical side, I take good care that my antenna coverage is acceptable in any direction (which requires more than one antenna on a carbon fuselage).

Bert
Ventus cM TW

[Stephen Damon]

It is amazing what we pay for gas, insurance, tow fees and hanger fees, and also life insurance. What is a parachute, the real life insurance not life insurance that pays your heirs. So what Flarm, another form of real life insurance, that will keep you from using your parachute incase you have too. Not to mention if you have had a collision with a sailplane or larger ship you will most likely be in bad shape. Yes I know chutes may need to be used with a collision. So to me, Flarm is just another form of real life saving insurance, that is pretty inexpensive for what it had and can do.

[Mark628CA]

I consider PowerFlarm to be a great asset in the cockpit. I have had a couple of warnings that may have made a difference. In one, I was thermalling with another glider when the warning went off. I was tempted to ignore it because I had "eyes on target" and I am sure the other pilot was watching me. A quick glance at the Flarm display indicated that the alarm was for someone in my low five o'clock position. Sure enough, a glance over my shoulder showed that another glider had joined us at speed and with a pullup into the circle. I was startled, but not freaked out- because I had the warning. If he hadn't had Flarm, it would have been much more disconcerting. I wish everybody had 'em, but I am not going to make a big deal out of it. I consider it one more source of insurance, just like my transponder, and yes, my glasses.

[ays...@gmail.com]

> On the technical side, I take good care that my antenna coverage is acceptable in any direction (which requires more than one antenna on a carbon fuselage).
>
> Bert
> Ventus cM TW

Bert,
Could you tell us where you place your multiple antennas on your carbon fuselage, and the type of antennas you are using.
Thanks,
Mark

[Tango Whisky]

I have an antenna splitter; one antenna is placed as a stripe antenna in the canopy to the side behind my head, and the other antenna is the standard "toothpick" placed next to a gear door.

Works well.

Bert
Ventus cM TW

[James Metcalfe]

At 21:44 24 November 2015, Andy Blackburn wrote:
>... Since you've owned several I guess it's safe to say there's
more benefit
>than downside. ...

Sorry to disappoint: I haven't owned any. These were 3 different
units in 2 club-owned two-seaters, flown in the French Alps
where Flarm was mandated by all the clubs in the area.

On balance Flarm *may* indeed be beneficial. But the purpose
of my post was to point out that there *are* significant
downsides. Pilots should be aware of these and avoid indulging
in gratuitously risky practices, under the illusion that Flarm will
protect them. They should also avoid making vigorous evasive
manoeuvres in response to Flarm alone: it is imperative to see
the threat before making anything other than a gentle
manoeuvre, perhaps a small wing-waggle to aid conspicuity.
This applies not only to threats from behind / blind spots. I am
sure that vigorous manoeuvres (unexpected by the other pilot,
who could see that the situation was under control) will result in
collisions - or perhaps already have ("such a shame ... and they
both had Flarm")

Finally I should say that my initial expectation of Flarm (and
BTW I love the technology!) was that it would significantly
reduce effective lookout - I'm afraid that's just my view of
human nature. That may or may not have happened - how could
I tell? However, as soon as I flew with Flarm, I was shocked to
discover what crazy manoeuvres other pilots were making,
which I had not experienced before, and which disappeared
when I next flew without Flarm.

>... I guess it depends on how you define [false alarm] ...

No, I didn't mean warnings given about empty space! I meant
collision warnings about a glider opposite me in the thermal, or
established in another, distant, thermal, or 500+ feet above or
below, etc. In other words, when no collision risk existed or
developed, regardless of how 'competitive' I felt.

J.

[James Metcalfe]

>Ramy

Indeed, I have not come across a Powerflarm unit, and don't know
what the differences are. But I don't feel that there is any
ambiguity in 'European' Flarm indications.
J.

[son_of_flubber]

Flarm just announced a new external antenna recommended for carbon and metal planes (Flarm and Powerflarm frequencies).

[jfitch]

I am curious about your experience with the interface. Did you just have the BF display, or was the Flarm also displaying targets on a moving map?

I have not had any Flarm warnings that would have saved a midair (3 years with it now). But I have always had Flarm targets displayed on the glide computer moving map, and so nearly always see them long before they could be considered a threat. Two times in those three years I have gotten an unexpected warning, though not close enough to require action to avoid collision. I use those events as a learning experience to see how I need to change my scans and operations, so that they do not happen again.

From this I conclude that the situational awareness, far away from an potential conflict, is more valuable for preventing potential conflicts in the first place than the actual warning facility.

Countless times that Flarm has identified and displayed glider within a km of me that I had not seen and might never have seen.

[Andy Blackburn]

On Wednesday, November 25, 2015 at 1:29:44 PM UTC-8, jfitch wrote:
>
> From this I conclude that the situational awareness, far away from an potential conflict, is more valuable for preventing potential conflicts in the first place than the actual warning facility.
>

Important observation. Pilots who fly in the thermal streets and convergence lines of the western US point this out pretty regularly. Head-to-head traffic at 17,999' can easily close at 5-6 statute miles per minute. In this case particularly (low-contrast, small head-on cross-section, potential for evasion maneuvers to make things worse with crossed wings) longer range situational awareness is critical to avoiding conflicts - often with a simple radio call to coordinate. Also a good reason to register with FarmNet - how many people really would be able to properly read and call out (or even recognize) an ICAO/Flarm ID in a time-constrained conflict situation? "AA8E2F, please turn right immediately!"

9B

[Richard]

I have also observed this situation many times in the Nephi OLC camps and contests. High closure rates and Configuring your PowerFlarm in the Stealth mode would make this situation a safety concern. It would limit the time to respond to a conflict situation. With the Stealth mode off these situation are visible for many miles and evasive action is easy.

Stealth mode on this situation is much more immediate and dangerous with little time to identify, find and respond to the threat.


Richard
www.craggyaero.com

[uncl...@ix.netcom.com]

On Saturday, November 21, 2015 at 9:29:27 PM UTC-5, Tim Taylor wrote:
> If you fly with other gliders, especially cross-country FLARM is the way to go.
>
> I have had several alerts at high altitude and high speeds that I would have never seen the other gliders in time without FLARM.
>
> I flew US Nats in 2009, 2010, and 2011. Three mid-airs, one fatal. Since 2012 all nats have had mostly FLARM equipped gliders, no mid-airs. I would not race without FLARM now and all our local group uses FLARM.
>
> TT

I recall a mid air(fatal) at Uvalde, and one at Parowan. Where was the third/
There is an implied cause and effect that is partially true. To get a better sense of this implication, it would be worthwhile to look to the preceding periods of time. Data point- the last fatal mid air before Uvalde was in the mid 80's at Ephata during a 70 glider race that was winner take all for team selection.
Do not misinterpret my comment. I use Flarm, and was a very early adoptor, but get quite tired of the well meaning true zealots over selling to make their case.
UH

[Andy Blackburn]

Here is the listing of all midairs for 1994-2013. There were 20 reported to FAA, so id doesn't include non-reported - which presumably would be more minor since they would unlikely include an insurance claim. It averages 1 per year. Uvalde had one fatal collision in 2010 and a non-fatal in 2012. There is some coding to show phase of flight and whether it was Glider-Glider, Glider-Towplane or Glider-GA as well as Takeoff, Landing or Mid-flight. Sorry for the poor formatting. A spreadsheet with all glider accidents in the US can be found here:

https://docs.google.com/spreadsheets/d/1Yx9bq_qivOzdo7BMqOQ3iJUvy7UoOul2hZIiMbiaav0/edit?usp=sharing


8/17/2012 Uvalde, TX SCHLEICHER ASG29-15M F-CIFB CEN12LA553A Non-Fatal 0 MIDFLT FLT MID G-G
8/17/2012 Uvalde, TX SCHLEICHER ASG29-15M D-6080 CEN12LA553B Non-Fatal 0 MIDFLT FLT MID G-G
6/7/2012 Sparks, NV SCHEMPP-HIRTH STANDARD CIRRUS N943SB WPR12LA250A Non-Fatal 0 MIDFLT FLT MID G-G
6/7/2012 Sparks, NV CENTRAIR C101A N101LV WPR12LA250B Non-Fatal 0 MIDFLT FLT MID G-G
8/4/2010 Batesville, TX ALEXANDER SCHLEICHER GMBH ASW 27-18 N8829A CEN10LA459B Fatal 1 MIDFLT FLT MID G-G
8/4/2010 Batesville, TX SCHEMPP-HIRTH VENTUS-2B N7470C CEN10LA459A Fatal 0 MIDFLT FLT MID G-G
6/15/2010 Parowan, UT SCHLEICHER ALEXANDER ASH 26 E N455S WPR10LA294A Non-Fatal 0 MIDFLT FLT MID G-G
6/15/2010 Parowan, UT SCHEMPP-HIRTH Ventus 2CT N514TW WPR10LA294A Non-Fatal 0 MIDFLT FLT MID G-G
2/6/2010 Boulder, CO SCHWEIZER SGS 2-32 N2472W CEN10FA115C Fatal 3 MIDFLT FLT MID TP-GA
11/28/2009 Middletown, CA SCHLEICHER ASW-27 N127AL WPR10FA068A Fatal 2 MIDLDG LDG MID G-TP
8/9/2008 Brackettville, TX Schempp-Hirth Ventus 2A N777UN DEN08LA137A Non-Fatal 0 MIDFLT FLT MID G-G
8/9/2008 Brackettville, TX AB Sportine Aviacija Genesis 2 N110RG DEN08LA137B Non-Fatal 0 MIDFLT FLT MID G-G
8/28/2006 Smith, NV Schleicher ASW27-18 N7729 LAX06FA277B Non-Fatal 0 MIDFLT FLT MID G-GA
4/1/2004 Oso, WA Glaser-Dirks DG-400 N400WJ SEA04LA063B Fatal 1 MIDFLT FLT MID G-G
4/1/2004 Oso, WA Glasflugel STD Libelle 201B N161D SEA04LA063A Fatal 0 MIDFLT FLT MID G-G
12/28/2003 Peoria, AZ Schleicher ASK-21 N274KS ANC04FA016B Fatal 4 MIDFLT FLT MID G-GA
5/1/1999 HILLTOWN, PA Burkhart Grob G-103 TWIN II N47938 IAD99FA041B Fatal 3 MIDFLT FLT MID G-TP
12/19/1998 OKEECHOBEE, FL Let L-13 N98KK MIA99LA051B Non-Fatal 0 MIDFLT FLT MID G-GA
6/29/1996 BOULDER, CO Burkhart Grob G103C TWIN III N103LM FTW96FA279B Fatal 2 MIDLDG LDG MID G-GA
5/8/1994 ELBERT, CO ROLLADEN-SCHNEIDER LS-4 N4MN FTW94LA151 Non-Fatal 0 MIDLDG LDG MID G-TP

[James Metcalfe]

At 21:29 25 November 2015, jfitch wrote:
>I am curious about your experience with the interface. Did you just have
>the BF display, or was the Flarm also displaying targets on a moving
map?
>
>I have not had any Flarm warnings that would have saved a midair (3
years
>with it now). But I have always had Flarm targets displayed on the glide
>computer moving map, and so nearly always see them long before they
could be
>considered a threat. Two times in those three years I have gotten an
>unexpected warning, though not close enough to require action to avoid
collision.
>I use those events as a learning experience to see how I need to change
my
>scans and operations, so that they do not happen again.
>
>From this I conclude that the situational awareness, far away from an
>potential conflict, is more valuable for preventing potential conflicts in

the

>first place than the actual warning facility.=20

>
>Countless times that Flarm has identified and displayed glider within a
km
>of me that I had not seen and might never have seen.

I have used only the 'butterfly' display. To be clear, of course I am
seeing target alerts all the time. That is not a problem, and even
occasionally interesting (such as when someone starts following).
The problem is with false collision warnings. Many pilots appear to (and
some of my pupils certainly do) find it almost impossible to resist turning

away from the Flarm direction of the 'threat', before they have seen the
target. That is dangerous, as I wrote in a post yesterday. And note that
the Flarm direction is often significantly different from the true
direction
(occasionally diametrically opposite), as it is track-based, not heading-
based.

I can see that my experience of Flarm in a very busy environment (the
French Alps) will be very different from that of those flying largely in
isolation (such as flatlands, particularly with what I would regard as high

cloudbases (I'm a Brit!))
J.

[Tim Taylor]

UH,

I should have been clearer, these were contests I was personally flying in.

We had three years in a row at contests where I was flying. Uvalde, Parowan, and then Uvalde again. I was beginning to wonder if this was becoming the norm or I was just really bad luck and should stop going to contests.

I flew at Mifflin in 2012, which was the first US nationals where PowerFlarm was available for many contestants. We were installing them during the rain days as you remember. Every contest after that has seen an increase in the number of pilots with PowerFlarm and I have not had to personally listen to the radio calls of the aftermath of a midair. After the last one at Uvalde I never want to hear it again.

I hope that PowerFlarm is mandatory at all Nationals in the future.

Tim (TT)

[Steve Koerner]

On Thursday, November 26, 2015 at 4:14:08 PM UTC-7, Tim Taylor wrote:
> UH,
>
> I should have been clearer, these were contests I was personally flying in.
>
> We had three years in a row at contests where I was flying. Uvalde, Parowan, and then Uvalde again. I was beginning to wonder if this was becoming the norm or I was just really bad luck and should stop going to contests.

I was at all three of those contests that Tim mentions. Listening to the radio traffic was nothing compared to listening to the wail of the wife being informed at Uvalde. I went home straight away on the determination that I would never fly another contest day.

The adoption of PowerFlarm allowed me to change that determination.

Someone here just said that they're tired of listening to people oversell PowerFlarm. I say that's not possible.

I find myself quite irritated when there are still typically one or two folks that will show up at a given contest without a PowerFlarm and that they are permitted to fly.

[jfitch]

James, if you are plagued by false alarms coming even from the wrong heading, I am all the more curious. I have not had any false alarms, perhaps some false negatives (probably should had been an alarm). Never from the wrong direction. Do you have the IGC files from a flight in which you remember that happening? It would be interesting to put it into SeeYou or other software (or even look at it in a text editor) to see what the accuracy of fix was. I have noticed that the Flarm GPS is typically reporting a larger error, and in some cases quite large. I'm not sure what the algorithms do with the precision of fix, but it seems like that is the most likely source of the errors you describe. For example the Flarm IGC file from my glider will show a typical precision of fix of around 3 - 4 meters, but sometimes it will go up to 30-40 for unknown reasons. The Air Avionics gps will show a precision of 1 - 2 meters on the same flight and might also go up in the same areas but not as much. Ridge flying in the Alps you might have the antenna shaded on one or more sides, which will increase the HDOP. The precision is the normally the last three digits of the B record in the IGC file. All of my flying is high altitude and with a clear view of the sky.

[Jonathan St. Cloud]

I thought there were two posts worth repeating below and hope everyone takes an honest look. Steve's post was poignant. I did hear the contest committee will require Flarm in stealth mode at contests, if you have one.

Shouldn't preserving life be our highest goal, even more important than winning a contest or being annoyed by the theoretical possibility of someone leaching for a few thermals?

For the price of a parachute you can save two lives.

Steve Koerner wrote:

I was at all three of those contests that Tim mentions. Listening to the radio traffic was nothing compared to listening to the wail of the wife being informed at Uvalde. I went home straight away on the determination that I would never fly another contest day.

The adoption of PowerFlarm allowed me to change that determination.

Someone here just said that they're tired of listening to people oversell PowerFlarm. I say that's not possible.

I find myself quite irritated when there are still typically one or two folks that will show up at a given contest without a PowerFlarm and that they are permitted to fly.

Richard from craggyaero wrote:

I have also observed this situation many times in the Nephi OLC camps and contests. High closure rates and Configuring your PowerFlarm in the Stealth mode would make this situation a safety concern. It would limit the time to respond to a conflict situation. With the Stealth mode off these situation are visible for many miles and evasive action is easy.

Stealth mode on this situation is much more immediate and dangerous with little time to identify, find and respond to the threat.

[jpg...@gmail.com]

Re "alarms coming from the wrong direction". Flarm uses true tracks not headings. On ridges with a high crosswind component and low airspeed an alert being indicated as being straight ahead may be from 30 degrees or more offset with respect to one's own glider heading. This was highlighted in 2007 in our Scottish Gliding Centre trial and should be understood and allowed for by users. There is no practical technical way to avoid that - not until we all have electronic compasses out on our wingtips anyway.

[David Salmon]

What James may be referring to is the fact that Flarm indications are in
relation to your ground track not heading. The extreme example is if
flying in very strong winds, say in wave, and actually going backwards.
Another glider coming from your 6 o'clock will actually show as head on.
This effect is still there in any cross wind.
This is a fundamental flaw in Flarm, which surely could be much improved by
building in a wind algorithm to correct the indication nearer to heading.
All navigation programs have them.
Dave

At 03:22 27 November 2015, jfitch wrote:
>On Thursday, November 26, 2015 at 2:45:07 PM UTC-8, James Metcalfe wrote:
>> At 21:29 25 November 2015, jfitch wrote:
>> >I am curious about your experience with the interface. Did you just
have
>> >the BF display, or was the Flarm also displaying targets on a

moving=20
>> map?
>> >
>> >I have not had any Flarm warnings that would have saved a midair (3=20

>> years
>> >with it now). But I have always had Flarm targets displayed on the
glide

>> >computer moving map, and so nearly always see them long before they=20

>> could be
>> >considered a threat. Two times in those three years I have gotten an
>> >unexpected warning, though not close enough to require action to

avoid=
>=20

>> collision.
>> >I use those events as a learning experience to see how I need to

change=
>=20

>> my
>> >scans and operations, so that they do not happen again.
>> >
>> >From this I conclude that the situational awareness, far away from an
>> >potential conflict, is more valuable for preventing potential
conflicts

>=
>in
>>=20
>> the
>> >first place than the actual warning facility.=3D20

>> >
>> >Countless times that Flarm has identified and displayed glider within

a=
>=20

>> km
>> >of me that I had not seen and might never have seen.

>>=20

>> I have used only the 'butterfly' display. To be clear, of course I

am=20
>> seeing target alerts all the time. That is not a problem, and even=20

>> occasionally interesting (such as when someone starts following).
>> The problem is with false collision warnings. Many pilots appear to

(and=
>=20

>> some of my pupils certainly do) find it almost impossible to resist

>turni=
>ng
>>=20

>> away from the Flarm direction of the 'threat', before they have seen

the=
>=20

>> target. That is dangerous, as I wrote in a post yesterday. And note

that=
>=20

>> the Flarm direction is often significantly different from the true

>> direction=20

>> (occasionally diametrically opposite), as it is track-based, not
heading-
>> based.

>>=20

>> I can see that my experience of Flarm in a very busy environment

(the=20

>> French Alps) will be very different from that of those flying largely

in=
>=20

>> isolation (such as flatlands, particularly with what I would regard as

>hi=
>gh
>>=20

>> cloudbases (I'm a Brit!))
>> J.
>
>James, if you are plagued by false alarms coming even from the wrong

>headin=

>g, I am all the more curious. I have not had any false alarms, perhaps

>some=

> false negatives (probably should had been an alarm). Never from the
wrong

>=

>direction. Do you have the IGC files from a flight in which you remember

>th=

>at happening? It would be interesting to put it into SeeYou or other

>softw=

>are (or even look at it in a text editor) to see what the accuracy of fix

>w=

>as. I have noticed that the Flarm GPS is typically reporting a larger

>error=

>, and in some cases quite large. I'm not sure what the algorithms do with

>t=

>he precision of fix, but it seems like that is the most likely source of

>th=

>e errors you describe. For example the Flarm IGC file from my glider will

>s=

>how a typical precision of fix of around 3 - 4 meters, but sometimes it

>wil=

>l go up to 30-40 for unknown reasons. The Air Avionics gps will show a

>prec=

>ision of 1 - 2 meters on the same flight and might also go up in the same

>a=

>reas but not as much. Ridge flying in the Alps you might have the antenna

>s=

>haded on one or more sides, which will increase the HDOP. The precision
is

>=

>the normally the last three digits of the B record in the IGC file. All
of

>=

[clewi...@gmail.com]

"This is a fundamental flaw in Flarm, which surely could be much improved by
building in a wind algorithm to correct the indication nearer to heading.
All navigation programs have them."

As another poster mentioned, you really need a heading input to achieve this. Whilst PNA's use drift while circling amongst other methods to determine the wind, they require frequent & sustained 'circles' to achieve this - not so good for wave & ridge. LX quote 3 circles from memory and all the operating notes warn of the associated unreliability. An attempt to use an algorithm to achieve this in Flarm would result in large variations in accuracy. Sometimes the relative bearings provided would be correct and sometimes, they wouldn't. Though currently an imperfect system, at least it's consistent.

CJ

[David Salmon]

What James may be referring to is the fact that Flarm indications are in
relation to your ground track not heading. The extreme example is if
flying in very strong winds, say in wave, and actually going backwards.
Another glider coming from your 6 o'clock will actually show as head on.
This effect is still there in any cross wind.

This is a fundamental flaw in Flarm, which surely could be much improved by
building in a wind algorithm to correct the indication nearer to heading.
All navigation programs have them.

Dave




At 03:22 27 November 2015, jfitch wrote:

>On Thursday, November 26, 2015 at 2:45:07 PM UTC-8, James Metcalfe wrote:
>> At 21:29 25 November 2015, jfitch wrote:
>> >I am curious about your experience with the interface. Did you just
have
>> >the BF display, or was the Flarm also displaying targets on a

moving=20
>> map?
>> >
>> >I have not had any Flarm warnings that would have saved a midair (3=20

>> years
>> >with it now). But I have always had Flarm targets displayed on the
glide

>> >computer moving map, and so nearly always see them long before they=20

>> could be
>> >considered a threat. Two times in those three years I have gotten an
>> >unexpected warning, though not close enough to require action to

avoid=
>=20

>> collision.
>> >I use those events as a learning experience to see how I need to

change=
>=20

>> my
>> >scans and operations, so that they do not happen again.
>> >
>> >From this I conclude that the situational awareness, far away from an
>> >potential conflict, is more valuable for preventing potential
conflicts

>=
>in
>>=20
>> the
>> >first place than the actual warning facility.=3D20

>> >
>> >Countless times that Flarm has identified and displayed glider within

a=
>=20

>> km
>> >of me that I had not seen and might never have seen.

>>=20

>> I have used only the 'butterfly' display. To be clear, of course I

am=20
>> seeing target alerts all the time. That is not a problem, and even=20

>> occasionally interesting (such as when someone starts following).
>> The problem is with false collision warnings. Many pilots appear to

(and=
>=20

>> some of my pupils certainly do) find it almost impossible to resist

>turni=
>ng
>>=20

>> away from the Flarm direction of the 'threat', before they have seen

the=
>=20

>> target. That is dangerous, as I wrote in a post yesterday. And note

that=
>=20

>> the Flarm direction is often significantly different from the true

>> direction=20

>> (occasionally diametrically opposite), as it is track-based, not
heading-
>> based.

>>=20

>> I can see that my experience of Flarm in a very busy environment

(the=20

>> French Alps) will be very different from that of those flying largely

in=
>=20

>> isolation (such as flatlands, particularly with what I would regard as

>hi=
>gh
>>=20

>> cloudbases (I'm a Brit!))
>> J.
>
>James, if you are plagued by false alarms coming even from the wrong

>headin=

>g, I am all the more curious. I have not had any false alarms, perhaps

>some=

> false negatives (probably should had been an alarm). Never from the
wrong

>=

>direction. Do you have the IGC files from a flight in which you remember

>th=

>at happening? It would be interesting to put it into SeeYou or other

>softw=

>are (or even look at it in a text editor) to see what the accuracy of fix

>w=

>as. I have noticed that the Flarm GPS is typically reporting a larger

>error=

>, and in some cases quite large. I'm not sure what the algorithms do with

>t=

>he precision of fix, but it seems like that is the most likely source of

>th=

>e errors you describe. For example the Flarm IGC file from my glider will

>s=

>how a typical precision of fix of around 3 - 4 meters, but sometimes it

>wil=

>l go up to 30-40 for unknown reasons. The Air Avionics gps will show a

>prec=

>ision of 1 - 2 meters on the same flight and might also go up in the same

>a=

>reas but not as much. Ridge flying in the Alps you might have the antenna

>s=

>haded on one or more sides, which will increase the HDOP. The precision
is

>=

>the normally the last three digits of the B record in the IGC file. All
of

>=

[David Salmon]

What James may be referring to is the fact that Flarm indications are in
relation to your ground track not heading. The extreme example is if
flying in very strong winds, say in wave, and actually going backwards.
Another glider coming from your 6 o'clock will actually show as head on.
This effect is still there in any cross wind.
This is a fundamental flaw in Flarm, which surely could be much improved by
building in a wind algorithm to correct the indication nearer to heading.
All navigation programs have them.
Dave




At 03:22 27 November 2015, jfitch wrote:

>On Thursday, November 26, 2015 at 2:45:07 PM UTC-8, James Metcalfe wrote:
>> At 21:29 25 November 2015, jfitch wrote:
>> >I am curious about your experience with the interface. Did you just
have
>> >the BF display, or was the Flarm also displaying targets on a

moving=20
>> map?
>> >
>> >I have not had any Flarm warnings that would have saved a midair (3=20

>> years
>> >with it now). But I have always had Flarm targets displayed on the
glide

>> >computer moving map, and so nearly always see them long before they=20

>> could be
>> >considered a threat. Two times in those three years I have gotten an
>> >unexpected warning, though not close enough to require action to

avoid=
>=20

>> collision.
>> >I use those events as a learning experience to see how I need to

change=
>=20

>> my
>> >scans and operations, so that they do not happen again.
>> >
>> >From this I conclude that the situational awareness, far away from an
>> >potential conflict, is more valuable for preventing potential
conflicts

>=
>in
>>=20
>> the
>> >first place than the actual warning facility.=3D20

>> >
>> >Countless times that Flarm has identified and displayed glider within

a=
>=20

>> km
>> >of me that I had not seen and might never have seen.

>>=20

>> I have used only the 'butterfly' display. To be clear, of course I

am=20
>> seeing target alerts all the time. That is not a problem, and even=20

>> occasionally interesting (such as when someone starts following).
>> The problem is with false collision warnings. Many pilots appear to

(and=
>=20

>> some of my pupils certainly do) find it almost impossible to resist

>turni=
>ng
>>=20

>> away from the Flarm direction of the 'threat', before they have seen

the=
>=20

>> target. That is dangerous, as I wrote in a post yesterday. And note

that=
>=20

>> the Flarm direction is often significantly different from the true

>> direction=20

>> (occasionally diametrically opposite), as it is track-based, not
heading-
>> based.

>>=20

>> I can see that my experience of Flarm in a very busy environment

(the=20

>> French Alps) will be very different from that of those flying largely

in=
>=20

>> isolation (such as flatlands, particularly with what I would regard as

>hi=
>gh
>>=20

>> cloudbases (I'm a Brit!))
>> J.
>
>James, if you are plagued by false alarms coming even from the wrong

>headin=

>g, I am all the more curious. I have not had any false alarms, perhaps

>some=

> false negatives (probably should had been an alarm). Never from the
wrong

>=

>direction. Do you have the IGC files from a flight in which you remember

>th=

>at happening? It would be interesting to put it into SeeYou or other

>softw=

>are (or even look at it in a text editor) to see what the accuracy of fix

>w=

>as. I have noticed that the Flarm GPS is typically reporting a larger

>error=

>, and in some cases quite large. I'm not sure what the algorithms do with

>t=

>he precision of fix, but it seems like that is the most likely source of

>th=

>e errors you describe. For example the Flarm IGC file from my glider will

>s=

>how a typical precision of fix of around 3 - 4 meters, but sometimes it

>wil=

>l go up to 30-40 for unknown reasons. The Air Avionics gps will show a

>prec=

>ision of 1 - 2 meters on the same flight and might also go up in the same

>a=

>reas but not as much. Ridge flying in the Alps you might have the antenna

>s=

>haded on one or more sides, which will increase the HDOP. The precision
is

>=

>the normally the last three digits of the B record in the IGC file. All
of

>=

[David Salmon]

At 13:30 27 November 2015, clewi...@gmail.com wrote:
>"This is a fundamental flaw in Flarm, which surely could be much improved

>b=
>y=20

>building in a wind algorithm to correct the indication nearer to

heading.=
>=20

>All navigation programs have them."
>
>As another poster mentioned, you really need a heading input to achieve

>thi=

>s. Whilst PNA's use drift while circling amongst other methods to

>determin=

>e the wind, they require frequent & sustained 'circles' to achieve this -

>n=

>ot so good for wave & ridge. LX quote 3 circles from memory and all the

>op=

>erating notes warn of the associated unreliability. An attempt to use an

>a=

>lgorithm to achieve this in Flarm would result in large variations in

>accur=

>acy. Sometimes the relative bearings provided would be correct and

>sometim=

>es, they wouldn't. Though currently an imperfect system, at least it's

>con=
>sistent.
>
>CJ
>
I only mentioned wave to illustrate the extreme example. Some error is
always there unless you are flying straight up or down wind. It is far
from consistent, the amount depends on the wind speed and your angle to it,
two variables.
So whats wrong with flying 2/3 circles, I often circle in wave. In any case
Paolo Ventrafridda developed a method for LK8000, of flying S & L on one of
several headings for say 10 secs at a constant airspeed.
If the will is there, it can be done, and even if slightly imperfect, it
would be better than the present almost always wrong indication.
However another approach would be a way of manually putting the wind into
Flarm, using the vario/navigator readout, which I'm sure everyone flying
with Flarm, is equipped with as well.
Dave

[jfitch]

James mentioned false alarms while diametrically opposed in thermals. That is highly unlikely to be due to wind drift.

[jpg...@gmail.com]

My colleague corresponded with Flarm during our Scottish trial in 2007 about the possibility of correcting the track/heading difference by wind estimates from circling and they said they would look it it but never introduced it. One of the obvious issues is that the modes of flight during which this difference is most obvious (ridge and wave) are less likely to entail a lot of circling. Also in mountain ridge flying we are more likely to experience varying local winds.

I think that trying to do this would introduce too many uncertainties and different calculations between gliders.

Even without Flarm a pilot who can't figure out his track versus heading when ridge flying would be looking out the window in the wrong place for conflicting gliders.

John Galloway

[Jim White]

At 06:34 27 November 2015, Jonathan St. Cloud wrote:
>I thought there were two posts worth repeating below and hope everyone

>take=

>s an honest look. Steve's post was poignant. I did hear the contest

>committ=

>ee will require Flarm in stealth mode at contests, if you have one.
>
>Shouldn't preserving life be our highest goal, even more important than

>win=

>ning a contest or being annoyed by the theoretical possibility of someone

>l=
>eaching for a few thermals? =20
>
This has been done over a thousand times. If you want a super safe
competition don't leave the ground.

Competition in gliders is inherently dangerous. But, Flarm or not, it is
not probable that you will have a fatal accident. Competition pilots weigh
up risk all the time and understand that by taking part they are taking a
risk.

The risk is small and made smaller by the use of Flarm. We should not avoid
risk as our highest goal. We should aim to collectively enjoy the sport
with an appropriate level of risk - mitigated by Flarm.

I believe Flarm should be mandated in competition and also believe it
should be used in stealth mode to allow handling and soaring skill to be
more relevant than radar reading and tactical flying.

Jim

[Dan Daly]

On Friday, November 27, 2015 at 12:32:47 PM UTC-5, jpg...@gmail.com wrote:
> On Friday, November 27, 2015 at 4:00:05 PM UTC, David Salmon wrote:

From the flarm.com press release of 2015-01-28, in part: "...It includes safety features that increase the effectiveness and robustness of collision warnings, further decreasing nuisance alarms, for example by taking into account wind."

It also talks about the FLARM TrackingServer release "...in spring 2015...", which as far as I can tell, didn't happen.

It would be helpful if someone from FLARM could comment on how the wind is taken into account, and the status of the TrackingServer. I note it would be convenient if they had a forum/bulletin board where customers of their expensive and complex products could interact with them and each other.

[Martin Gregorie]

On Fri, 27 Nov 2015 09:31:17 -0800, jfitch wrote:

> James mentioned false alarms while diametrically opposed in thermals.
> That is highly unlikely to be due to wind drift.

... which is something I've never experienced, but maybe I've never
shared a thermal with an idiot since I've had FLARM fitted. That said, at
my club there was one collision in a thermal between two FLARM-equipped
gliders. AFAICT from talking to the pilots, one of them was far from
being on the diametrically opposite side of the thermal and then misread
the intentions of the other pilot. Under these conditions FLARM won't
help because the time between its warning being triggered and the
collision is likely to be too short for either pilot to do anything about
it.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[jfitch]

The short warning you get in thermals is a limitation of Flarm. Mitigated by a very good tactical screen of which there are unfortunately few examples. One of the compromises that appear to have been made to eliminate false alarms in thermals is a very short warning distance. I have flown close to other gliders in thermals (yes they were aware) to see just when the alarms occur. I'm not criticizing Flarm for this, something I think they had to do. Too many extraneous alarms is as bad as no alarms at all.

On a good tactical screen (the original Winpilot remains the very best by a wide margin) gives you a 3D map of all the gliders in the thermal near your altitude. Very easy at a glance to see where everyone is. I do not know of another display with this capability but I found it very informative. Unfortunately the original Winpilot doesn't work with modern equipment anymore, so the facility has been lost.

[XC]

I am still seeing a lot of misinformation out there. I have two points to make supporting the use FLARM stealth mode in contests.

1) Stealth mode still allows the display and audio warning for threat aircraft no matter what the range.

and

2) FLARM used without stealth mode leads to an invalid score sheet. This is more true in eastern U.S. or European contests with lower working bands and more potential landouts.


First, I'd like folks to understand that FLARM sends two different messages to the display devices.

The $PFLAU sentence has priority and contains info about intruder alerts and obstacles. The contest ID is removed in stealth mode. Alerts are unaffected no matter the range. It really works quite well with the algorithm the FLARM people have developed.

The $PFLAA sentence is info about proximate aircraft displayed on your device. In stealth mode this info limited to aircraft within 2 km and +/- 300 meters vertically. Stealth or competition mode also removes ID, climb rate, track and speed from the display output for these proximate aircraft. It continues to use these variables to calculate the collision avoidance algorithm in $PFLAU.

Folks should read FLARM release notes for FLARM 6.02 Firmware, FLARM data port specification TFD-12 and FTD-14 FLARM Configuration Specification for full understanding. Anyway, we found in Elmira last year it worked quite well and the contest was definitely still fun for all.

High Western conditions versus lower Eastern (US) conditions: Without the use of stealth mode, in a contest with a lower working band, a pilot relying on FLARM technology can drive harder without fearing a landout, knowing there are gliders ahead to mark thermals. This does work in the east where thermals are closer together and you may be one thermal away from a landout. Even a mediocre pilot who might not even be able to get around the course by him/herself that day can use FLARM to pick the best thermals, found by others, and do fairly well on the score sheet. I agree in most cases this will not get a pilot the win. I do believe FLARM without stealth mode jumbles the middle of the score sheet and leads to an invalid result.

So, do what you want when flying cross countries at home. However, I go to contests to see how I am stacking up against some great pilots. Stealth mode (soon to have more appropriate name) is the way to go here. It retains all the safety features it was designed to deliver, keeps your eyes outside of the cockpit where they should be and at the end of the contest period the score sheet shows which pilots have the best soaring skills.

XC

[ucanem...@gmail.com]

"The $PFLAA sentence is info about proximate aircraft displayed on your device. In stealth mode this info limited to aircraft within 2 km and +/- 300 meters vertically. Stealth or competition mode also removes ID, climb rate, track and speed from the display output for these proximate aircraft. It continues to use these variables to calculate the collision avoidance algorithm in $PFLAU. "

Imagine two gliders flying in Utah at the nationals at 17,000 feet 100 knots indicated under cloud street on opposite courses. Say the 100 knots indicated is 134 knots true. Closure rate 268 knots or 496 kph, covering 2Km is about 1/4 a second warning. Just saying.

[Tango Eight]

On Friday, November 27, 2015 at 3:49:53 PM UTC-5, ucanem...@gmail.com wrote:

> Imagine two gliders flying in Utah at the nationals at 17,000 feet 100 knots indicated under cloud street on opposite courses. Say the 100 knots indicated is 134 knots true. Closure rate 268 knots or 496 kph, covering 2Km is about 1/4 a second warning. Just saying.

What is it that you think is going to go wrong in stealth mode? My reading of flarm's docs says alerts will be delivered normally, i.e. first warning about 25 seconds before closest approach.

T8

[Jonathan St. Cloud]

With all due respect, it should go without saying that if you are going to quote someone, do not later paraphrase with a completely new meaning!!!! What I said is "shouldn't preserving life be our highest goal". I did not say nor did I mean what you later paraphrased as "We should not avoid risk as our highest goal". Those are your words intentional miscontrueing plain simple English that I clearly communicated to anyone with a fourth grade education! Thank you very much.

On Friday, November 27, 2015 at 9:45:06 AM UTC-8, Jim White wrote:
> At 06:34 27 November 2015, Jonathan St. Cloud wrote:

> >Shouldn't preserving life be our highest goal, even more important than
> >win=
> >ning a contest or being annoyed by the theoretical possibility of someone
> >l=
> >eaching for a few thermals? =20
> >

>..Jim White wrote:
>
> ...Competition in gliders is inherently dangerous. But, Flarm or not, it is

> not probable that you will have a fatal accident. Competition pilots weigh
> up risk all the time and understand that by taking part they are taking a
> risk.
>
> The risk is small and made smaller by the use of Flarm. We should not avoid
> risk as our highest goal. We should aim to collectively enjoy the sport

> with an appropriate level of risk - mitigated by Flarm....
>

> Jim

[XC]

Once again I'll say - That is not the way it works. The 2 km does not apply to an aircraft determined to be a threat. In the case stated above the alarm and display would go off at x secs regardless of the distance. I am not sure what the number of seconds is but it is based on a safe reaction time. The warning would be limited by the reception range of the FLARM set up and any limitations the pilot has set in $PFLAU portion of the configuration file. This would be true stealth or not. The specifics of how the threat is painted and the audio warning is left to manufacturer of the display device.

Proximate aircraft which are not a threat are only displayed if they are within 2 km and +/- 300 m, etc.

XC

[Martin Gregorie]

On Fri, 27 Nov 2015 12:49:50 -0800, ucanemailmoi wrote:

> Imagine two gliders flying in Utah at the nationals at 17,000 feet 100
> knots indicated under cloud street on opposite courses. Say the 100
> knots indicated is 134 knots true. Closure rate 268 knots or 496 kph,
> covering 2Km is about 1/4 a second warning. Just saying.
>

I think its a bit longer than that.

A closing speed of 496 kph is 138 m/s, so it will take 14.5 seconds
between first warning at 2km separation to the collision if nobody takes
avoiding action.

[Mark628CA]

From a previous post:

"Say the 100 knots indicated is 134 knots true. Closure rate 268 knots or 496 kph, covering 2Km is about 1/4 a second warning. Just saying."

Uh- I don't think so. 2 m in .25 sec = 8 km/sec = 480 km/min = 28,800 km/hr = 17,856 mph = orbital velocity.

Obviously not a script writer for "The Martian."

"Interstellar," maybe.

[Martin Gregorie]

Yes - agreed. I wasn't criticising FLARM at all for this. IMO the reality
of thermal gaggles is that everybody *must* maintain situational
awareness in a multiply occupied thermal. Thinking about it a bit
further, if everybody at more or less the same height in a thermal flies
sensibly, the time to go from safe to collision takes enough time to make
avoidance fairly easy. It would take at least one pilot to be grossly out
of position to make a collision imminent (think leaving by blasting
across the centre or getting too close behind or below another glider).
FLARM will spot a dangerous joining manoeuvre but whether the warning
would do you any good may depend on where the other glider(s) in the
thermal are, i.e. do you have an escape route that doesn't endanger
anybody else.

[jfitch]

On Friday, November 27, 2015 at 11:57:18 AM UTC-8, XC wrote:

Yet peculiarly in the pilots poll, twice as many pilots said non-stealth Flarm enhanced enjoyment of a contest, as wanted it mandatory. In nationals 30% wanted mandatory stealth, in regionals 20%. Yet 40% said keeping track of the other gliders through non-stealth flarm enhanced their enjoyment of the contest. Looking at all of the responses to those three questions one can only conclude that a significant number of pilots do not want to enjoy contests. Maybe that's why participation is declining?

[Mark628CA]

Oops!

Make the first line read "2 KM in .25 sec"

[Andy Blackburn]

I don't think that's the issue people are raising. The only way you get a warning from Flarm is if the glider is on an intersecting track within a fairly narrow "uncertainty cone". It is only valid over any distance for gliders that don't maneuver. As we all know that is rarely the case - glider maneuver all the time.

The issue is that a glider that hooks a turnpoint or leaves a thermal or otherwise changes course can go from being invisible to a threat at a distance that is roughly 10-15 seconds away from impact.

The RC is aware of this shortcoming and is engaging with the IGC and Flarm to ensure that course changes cannot generate surprise threats without proper IDs (remember, a radio call to a known Contest ID to coordinate evasive action is the best practice in head-to-head scenarios). It is particularly an issue for high-altitude, high speed street flying that is common in the US west and other places where converging speeds can top 350 MPH. At 2km for Flarm stealth mode this is a 12 seconds of warning. Most pilots who fly under these conditions use longer range situational awareness to avoid conflicts rather than having to react with very little time to: 1) identify and orient the threat, 2) determine the best course of action, 3) raise the other glider on the radio by Contest Number - or worse, Flarm ID (who memorizes theirs?), 4) coordinate an evasive maneuver that isn't "you zig, I zag". Ask the guys that fly the convergence and strong streets out west all the time. Less than a minute to do all that concerns them - deeply. I asked them and got their feedback.

Also, I don't think if you ask the guys in the middle of the scoresheet they'd be super wild about deliberately creating more landouts (and everything that goes with that in terms of hassle and the odd insurance claim) out of some sense that missing a thermal on a random glide that someone who flew 1/16 of a mile to the east stumbled into for a save somehow is more valid. Mostly we devalue contests with landouts because we think landouts are an indicator of less valid conditions. In fact we polled people and they said what they think.

But that's another discussion about philosophy. :-)

9B

[Andy Blackburn]

On Friday, November 27, 2015 at 2:12:24 PM UTC-8, Martin Gregorie wrote:
> On Fri, 27 Nov 2015 12:49:50 -0800, ucanemailmoi wrote:
>
> > Imagine two gliders flying in Utah at the nationals at 17,000 feet 100
> > knots indicated under cloud street on opposite courses. Say the 100
> > knots indicated is 134 knots true. Closure rate 268 knots or 496 kph,
> > covering 2Km is about 1/4 a second warning. Just saying.
> >
> I think its a bit longer than that.
>
> A closing speed of 496 kph is 138 m/s, so it will take 14.5 seconds
> between first warning at 2km separation to the collision if nobody takes
> avoiding action.
>

LOL. I think he meant 1/4 minute. At 110 kts at 17,500 and 40 deg F it's closer to 1/6 of a minute.

9B

[XC]

The case that folks are making regarding high converging speeds are in clouds streets, wave and ridge lift. Theses are predictable situations that are easily handled by the FLARM algorithm. In the worse case scenario, 10-15 seconds is plenty of time to alter course to avoid a mid-air

The argument that a radio call to a known ID is the best course of action is false. The best way to avoid a mid-air is to turn to avoid the danger using predetermined right-of-way rules, not to establish radio communication and coordinate a plan.

Lastly, good glider pilots don't stumble into saves. They know where the lift is likely to be. They manage risk to get there with altitude to use it and have a back up plan. Some people are good at this and others are not as good. The score sheet should reflect this fact. The rules should ensure the integrity of the sport and keep it the adventure it was always supposed to be - not water it down. You'd attract a lot more people to the sport by having soaring heroes like we used to have rather than trying to placate everyone's desire to make it home for dinner.

[Andy Blackburn]

On Friday, November 27, 2015 at 6:43:55 PM UTC-8, XC wrote:
> The case that folks are making regarding high converging speeds are in clouds streets, wave and ridge lift. Theses are predictable situations that are easily handled by the FLARM algorithm. In the worse case scenario, 10-15 seconds is plenty of time to alter course to avoid a mid-air

Disagree - totally - this is inconsistent with experience.

>
> The argument that a radio call to a known ID is the best course of action is false. The best way to avoid a mid-air is to turn to avoid the danger using predetermined right-of-way rules, not to establish radio communication and coordinate a plan.
>

Ask anyone who it has happened to. "XC please turn right" beats guessing which way you are going to go and even the Flarm guys recommend strongly agains making an impulsive turn because even if both glider guess to turn away from each other it turns their wings into a perfect "X". Not good.

> Lastly, good glider pilots don't stumble into saves. They know where the lift is likely to be. They manage risk to get there with altitude to use it and have a back up plan. Some people are good at this and others are not as good. The score sheet should reflect this fact. The rules should ensure the integrity of the sport and keep it the adventure it was always supposed to be - not water it down. You'd attract a lot more people to the sport by having soaring heroes like we used to have rather than trying to placate everyone's desire to make it home for dinner.

This is folklore - if you really believed that we should devalue speed days and not devalue days where one "hero" gets around and everyone else lands out - yet we do the opposite. Look at Elmira - many of the top PRL guys got knocked out on the landout days. I'd say bunk to the contention that superior skill has very much to do with it above a certain level of experience.

9B

[Tim Taylor]

On Friday, November 27, 2015 at 7:43:55 PM UTC-7, XC wrote:
> The case that folks are making regarding high converging speeds are in clouds streets, wave and ridge lift. Theses are predictable situations that are easily handled by the FLARM algorithm. In the worse case scenario, 10-15 seconds is plenty of time to alter course to avoid a mid-air
>
> The argument that a radio call to a known ID is the best course of action is false. The best way to avoid a mid-air is to turn to avoid the danger using predetermined right-of-way rules, not to establish radio communication and coordinate a plan.
>
> Lastly, good glider pilots don't stumble into saves. They know where the lift is likely to be. They manage risk to get there with altitude to use it and have a back up plan. Some people are good at this and others are not as good. The score sheet should reflect this fact. The rules should ensure the integrity of the sport and keep it the adventure it was always supposed to be - not water it down. You'd attract a lot more people to the sport by having soaring heroes like we used to have rather than trying to placate everyone's desire to make it home for dinner.
>
> XC

Sean,

I have seen several days at Nephi in the last two years plus many days at Parowan and Uvalde where 15 to 20 seconds is marginal for planning. While I really like Flarm, I also recognize that interpreting a warning and then deciding how to respond takes time and can be very disconcerting at high speeds. I am still not used to the fact that I have to pull my focus back in the cockpit just when I really need to be scanning for the traffic.

Two years ago on a contest day we had a single street the last few miles into and out of the first turnpoint. We were flying at over 110 knots indicated at about 13,000 feet. I was flying with IRS (Mark) on my right wing and fortunately we had about five miles Flarm range because we were head-on and same altitude with 9B (Andy) and ZL (Dave) running at the same speed in the opposite direction. Andy and I were coordinating from about 4 miles apart to maintain separation but I still never saw ZL when the two passed. Andy went between Mark and me both horizontally and vertically with only a hundred feet vertical separation (I show IRS and 9B as close as 4 feet vertically as we passed). It would be easy to turn to avoid one warning only to cross the path of a second glider if you did not know they were coming.


I don't have a perfect answer on the stealth versus not discussion. I understand that non-stealth changes the game dramatically but I also like having more warning time to prepare for meeting other gliders when we are closing at 250 mph. I am not ready to make stealth required at all contests until we have some experience with it under western conditions.

Tim

[ucanem...@gmail.com]

My math is correct, my typing was not: 1/4 of a minute warning! That is actually not much time to be alerted, accept the alert, come up with a plan of action and react. This is why it is better to have Flarm set you can see the gliders coming your way, while there is enough to plan not just react. Western flying at speed and altitude under mountain generated clouds streets is different than eastern flying, and requires its own set of safety parameters and flying style. Not every peg fits in every hole.

[jpg...@gmail.com]

1/4 minute is ample time - that is about when Flarm issues its first acoustic collision alert. I have participated in several head on collision scenarios during a Flarm trial. Even waiting until the third level of Flarm alarm before reacting all that is required is a gentle change of direction a few degrees. The key thing is that Flarm has alerted you to visually acquire the potential threat that you might not otherwise have done.

BTW my strong belief is the the first response to a Flarm acoustic alert should be to look along track, to see a possible head on threat, before looking at the visual display. Head on threats are the most high energy.

There is far too much concentration on Flarm visual displays (eyes down) instead of the acoustic alert (eyes outside).

[mur...@earthlink.net]

I sounds like coordination between gliders has limited usefulness. It involves several extra steps, heads down time, plus everyone has to be working together. I agree with the fellow who said audio warning plus eyes outside is the best way to go.

Have you tried stealth mode in a contest? It works well. Try it and I think you find it is fine.

Perhaps a better path for you and Andy would be to get involved in the ongoing discussion about the best range to show proximate traffic in competition (stealth) mode. (Remember intruder traffic is displayed at any range the FLARM set up can detect). Perhaps the range should be configurable to show proximate traffic farther away in western contests. The algorithm could also be modified to identify more threats. These are all possibilities. I still see no need to display contest ID, climb rate, i.e. all the competitive stuff. Relative altitude is displayed.

Also, I think we can agree a few degrees of bank is all that is need to avoid traffic at 110 kts.

XC

[Mike the Strike]

I have some experience of head-on meetings under cloud streets and narrowly avoided a couple of collisions in my pre-Flarm days. Closing speeds are impressively high and the interval between seeing a glider head-on and avoiding it impressively short. Fifteen seconds warning is almost certain to be a lot better than you have visually.

However, I cannot understand how anyone believes that reducing the amount of information on glider positions by using stealth mode does anything other than reduce safety. I believe the concern over leeching is seriously misplaced.

Mike

[John Godfrey (QT)]

An issue with this argument is the assumption that integrating an in-cockpit display into ones awareness has no cost. I believe this is a fallacy. Anything that directs your attention inside the glider potentially adversely affects safety. Folks are making the "situational awareness" argument with the premise that sll objects you need to be aware of are FLARM equipped and that all FLARMs are operating correctly.

WRT thermals, one prior poster observed that Winpilot is excellent for displaying gliders in a thermal. The idea of someone in a thermal not looking out the window 100% of the time is troubling to me. There have been at least two instances I am personally aware of where FLARM equipped gliders have collided in a thermal.

QT

[clewi...@gmail.com]

"So whats wrong with flying 2/3 circles, I often circle in wave. In any case
Paolo Ventrafridda developed a method for LK8000, of flying S & L on one of
several headings for say 10 secs at a constant airspeed.
If the will is there, it can be done, and even if slightly imperfect, it
would be better than the present almost always wrong indication.
However another approach would be a way of manually putting the wind into
Flarm, using the vario/navigator readout, which I'm sure everyone flying
with Flarm, is equipped with as well. "

Nothing wrong with circling, but pilots aren't going to stop and circle just to improve the accuracy of their wind calculation. It comes down the to quality of the data being fed to the device. Whether derived internally or fed from an external source (such as the PNA's you suggest), unless it's always accurate it, it's going to result in inaccurate relative bearing information. To the best of my knowledge, Flarm presently resolves traffic warnings as a relative bearing based on *track*. It may not always be accurate with regards to *heading* but at least it's consistent and thus can be allowed for by the pilot. The only time things go to pot is when roughly holding position in wave. If Flarm was alternating between heading and track based relative bearings, based on the accuracy of the wind solution at the time, you'd never know where to look.

CJ

[John Carlyle]

Sean, you say you're against using Flarm in non-stealth mode because "it leads to an invalid score sheet", essentially arguing that mediocre pilots could use Flarm for electronic leeching.

You've been a superior contest pilot for long enough that I think you're forgetting (1) the intensive learning that happens during contests by mediocre pilots and (2) just why those mediocre pilots are at the contest. They're at the contest because they're trying to become better pilots, and they learn that by observing what superior pilots are doing.

I submit that Flarm, in addition to being a safety device, offers a superior method for observing where other gliders are located, allowing a mediocre pilot to learn better how to read the sky and terrain. It's possible that some could use Flarm for leeching, but that behavior would show up in the IGC files and could be easily dealt with (with an unsporting conduct penalty).

-John, Q3

[Richard]

John,

I agree, but! Why would we want to allow mediocre pilots to get a chance for all the woman and money?

This is a game for enjoyment and those that think differently are already racing very few like minded pilots.

Richard

[Jonathan St. Cloud]

I am always perplexed by the argument that a device that gives you more situational awareness has a cost because you are not looking outside for one bloody second, rather looking inside at something that tells you what you have not been able to see by looking outside. Ever heard of synthetic vision? I have over two thousand hours flying much faster aircraft than gliders equipped with Mode S traffic position displays and/or TCAS. These amazing devices, yes including Flarm, are more about giving you the entire picture that you cannot see, so you can avoid the drama of extreme near misses or of the actual collision. A second looking at an instrument inside the cockpit can tell you more than you have seen with your scan the last 30 or more seconds.

I am not sure why the gliding community resists technology when we fly airfoils that are designed by some of the fastest computers on the planet. This debate is reminiscent of the GPS debate of 18 or so years ago. Looking back on that debate does anyone think the anti-GPS opinion was right or just plain silly. The head in the cockpit was used by the anti-GPS faction also. Imagine taking photos of turn points. Think of the fancy new instruments we have that would not have been developed had the anti-GPS debate won.

Maybe the Amish have a gliding club with bungee cords, wood and fabric gliders and pellet varios.

No vitriol intended, just trying to make a point that seems so obvious to me and with my real world experience using traffic awareness technology. Again no offense intended to any parties including the anti-GPS faction who were so clearly wrong and short sighted :)

[Dan Marotta]

All this talk about speed and distance.  Why not combine the two and think in terms of time?

With a first warning at, say, 15 seconds, make a gentle turn according to the right of way rules.  What could be simpler?  Why would you need anything more complex?  The algorithm will compute tracks and issue warnings.  Look outside, make a gentle turn, and enjoy the flight.  Talking about "crossed wings" clouds the issue under discussion.  If you make a small course correction at the initial collision warning, getting that close won't happen.  That's more of a thermalling thing, not a near head-on approach.  Worrying about someone getting a bit of a lead in a contest at the risk of getting run over is, in a word, stupid.

Full disclosure:  I do not use Flarm, but that's not to say that it's not on my list of future upgrades.

--
Dan, 5J

[XC]

John and Richard,

I do remember my cross country skills improved greatly when I was mentored at home by W3. I quickly found that by following him around the course I stopped making my own decisions and I got nothing out of it. We then went to a system where we started together for fun, soon split off to follow our own decisions and raced around the course. Comparing my decisions to a seasoned pilot at the end of the day is very useful and much more gratifying.

I go to contests to do the same thing - put up my best effort against the other pilots at the contest and compare the results in the end. I enjoy this very much. I recommend flying your own flight to anyone who enjoys getting better.

XC

[John Carlyle]

Richard,

Ah, yes, the women and the money - silly me! Or were you referring to the woman I annoy and the money I spend to attend contests?

-John, Q3

[XC]

John and Richard,

I do remember the days when I had no clue how to fly cross country. Luckily, I had an experienced pilot like W3 to fly with at the home base. I quickly realized that following him was no way to get better. Instead, we have gone to setting a task and starting together for fun. After a few clouds we end up making different decisions and splitting off. After racing around the course we compare results to see who did it better and how. This is really fun and much more gratifying.

I go to contests to do the same thing. I put up my best effort and compare it to other pilots at the end of the day. Contests are a great way to improve your soaring skills. I recommend making your own decisions and flying your own flight to anyone who enjoys getting better.

Displaying other pilot's contest ID's and climb rates via FLARM not only make the results of other pilots at the end of the day less meaningful, but each pilot will not have the same sense that they accomplished the flight themselves. Not entirely so, but to some extent. Surely, racing pilots will make some use of this data if available. This is what I mean by watering down the sport and decreasing the adventure of it all.

XC

[Andy Blackburn]

On Saturday, November 28, 2015 at 5:13:00 AM UTC-8, mur...@earthlink.net wrote:
>
> Perhaps a better path for you and Andy would be to get involved in the ongoing discussion about the best range to show proximate traffic in competition (stealth) mode. (Remember intruder traffic is displayed at any range the FLARM set up can detect). Perhaps the range should be configurable to show proximate traffic farther away in western contests. The algorithm could also be modified to identify more threats. These are all possibilities. I still see no need to display contest ID, climb rate, i.e. all the competitive stuff. Relative altitude is displayed.

Good idea. As it happens, that's exactly what's happening. I agree climb rate display is not needed, but undithered altitude difference is important as is Contest ID - or you have no solution to the "you zig, I zag" problem - this is also an issue with ridge flying.

Don't forget what got one of our friends killed in Uvalde involved multiple ship formations - which also happens a lot. Who is the alarm for? Is there another glider to one side or the other? You don't know until you have only 10 seconds to (yikes!) look at the display and decide - and hope the other guy(s) don't null out your adjustment. There really is no perfect substitute for better situational awareness. Most pilots I talk to who fly these conditions think it's better to avoid a conflict than react to one where you may (or may not) need to make an impulse move because you don't know which way to turn (and the other pilot(s) may not make complementary turn decisions). Also keep in mind that you are more likely to get an alarm from a glider maneuvering to become a threat than is right on a collision course from max range all the way in. The odds that you will have a track on a glider from max range (and hold it) is low. The idea that Flarm will generate an alarm for conflicts at max range is only a partial solution.

> Also, I think we can agree a few degrees of bank is all that is need to avoid traffic at 110 kts.

That's more true the further out the target is so you are making my point for me. A couple of degrees of bank is an easy fix 4-5 miles out because you can observe the change in tracks, it's less certain at 5-15 seconds and there is no backup plan when one glider goes right and the other goes left - that's a very bad oops!

This is analogous to two people walking down the hall at each other. Flarm open mode is with the lights on. Stealth mode is in a pitch black hallway where each person has a small, narrow beam flashlight. Now try it while you're running. Then try it while you're running a gentle slalom.

Note: I realize we flew for years without Flarm and only killed a handful of guys per decade. My main point is that if we have the technology installed to make most of that go away that is amazing! Why are proposing to go to a bunch of trouble to mandate less and require people to enforce rules that make it ANY worse when even the strongest advocates for stealth mode argue that it mostly affects middle of the scoresheet guys on marginal days (days that we already devalue as having a lot of luck factor) and the main benefit is we get more landouts - presumably with some more landout accidents and unhappy pilots. Generating more landouts isn't high on my list of priorities - it's a recipe for a smaller sport.

The pilot community was pretty clear they like flying with more situational awareness - for safety as well as enjoyment reasons. If we chase a lot of pilots out of racing to OLC and XC camp formats (or something else) how valid will contest result be then? Finishing third out of four competitors when the fourth guy was only fourth because he landed out on a marginal day is hardly a podium placing to take much pride in.

9B

[Andy Blackburn]

True - or mostly true. I learn a bit every time from observing another pilot's decision-making. I think it's important to make your own decisions and observe when others make different ones - what did they see? - what was their reasoning? - did I have a better idea? Sometimes you learn more by going your own way and playing your hunch out, seeing what happens down course, sometimes you learn more by making the mental note that you'd have done it differently, that it was probably not as good a choice and staying together for the next decision. The important point is to always be thinking about what you think you should be doing next. You can't learn with your brain turned off - plus it's super annoying to the people with their brains turned on.

9B

[mur...@earthlink.net]

The initial thought I had at Uvalde is the he probably had his head down adjusting the scale on his PDA as he went into (out of) the turn. This is just speculation but it truly was what we were thinking on that day.

Andy, you're really overselling this. I never said I was in favor of more land outs, just that pilots should not be able to artificially increase their achieved speeds by routinely using other people's thermals which are conveniently labeled with climb rates.

Everyone should count out loud 10 seconds as a worse case scenario and see if it enough time to avoid a glider or a formation of gliders while looking outside your glider. I think it is. If folks want to go back in forth between outside and your cockpit display and analyze things then they are going to get caught looking in the wrong place.

XC

[Richard]

XC

I absolutely agree compromising safety will increase the adventure of it all.

As for the approximately 14 seconds you get at 2km. Let us start the count after you identify a head on glider with a closure rate of 260 knots. Assuming you ever see the glider. Eyes don't see point sources that don't have relative movement. I suggest much less time to avoid.

Richard

[John Carlyle]

Sean,

I'm not saying "follow the better pilots", I'm saying be aware of where other pilots are and factor that into your own decision making. That way, if you become aware you're out in left field because you read the sky wrong, you have a chance to correct your mistaken judgment before it's too late.

I agree with you, following someone without thinking (ie, leeching) teaches you nothing. But going to a tricky site, making poor decisions and landing out denies you a lot of in-flight learning opportunity that you sacrificed a good deal of time and money to try and get.

What I'm saying is that less experienced pilots can use non-stealthed Flarm to get hints during contest flights and use those hints to make their own decisions without leeching. Denying them those hints is equivalent to teaching someone to swim by throwing them in deep water.

-John, Q3

[Andy Blackburn]

On Saturday, November 28, 2015 at 11:15:23 AM UTC-8, mur...@earthlink.net wrote:
>

> The initial thought I had at Uvalde is the he probably had his head down adjusting the scale on his PDA as he went into (out of) the turn. This is just speculation but it truly was what we were thinking on that day.
>

We'll never know what Chris was doing and I'm loathe to get too much deeper into a painful memory in this discussion. I did talk to the other pilot, who's a friend, at great length - it's in the Soaring article on Flarm from 2014. Suffice it to say at least one person was looking and scanning pretty hard. It's a very challenging visual problem for humans - we weren't bred to pick these kinds of thing up.

>
> Andy, you're really overselling this. I never said I was in favor of more land outs, just that pilots should not be able to artificially increase their achieved speeds by routinely using other people's thermals which are conveniently labeled with climb rates.
>

I've always just been looking for the scenario that is being solved for. Either there will be more landouts from missed saves or there's not much benefit being generated. If I accept your point but assume zero incremental landouts, just that one course line might have a superior climb in it and some other line might not. First, that's one scoop skill, one scoop local knowledge and one scoop dumb luck). I wager for the non-random part it benefits different pilots on different days by a minute or two - or 8-14 points on the days when it works. So you're up 8 one day, no benefit three other days and down 14 another day for minus 6 points net at the end of a week. It's so far down in the noise of random events at a contest that the signal to noise ratio isn't even measurable. Add to that the fact that pilots who systematically take other people's thermals rather than their own generate about 10-15% slower climbs on average (actual data from suspected leech-heavy contests). At the end of the contest you end up with people who try to use Flarm to follow being down several hundred points for having been a sucker - not counting any other shortcomings they may have.

I'm fine with deleting climb rates, I find them useless anyway, they are snapshots with no total energy - I normally pick up the pullup (+10 its or so), followed by a lot of randomness.

>

> Everyone should count out loud 10 seconds as a worse case scenario and see if it enough time to avoid a glider or a formation of gliders while looking outside your glider. I think it is. If folks want to go back in forth between outside and your cockpit display and analyze things then they are going to get caught looking in the wrong place.

Should be fine. Hope it'll be fine - until you see the other guy in quartering trail behind the alarm target or realize the target glider turned right just as you turned left. It's hard to pick that up on the display (do you look out the canopy or down at the display to sort that out?) at one update per second so you need a couple of updates to see where he went - or you try to pick him up by looking in that direction, but your odds of seeing him in time are about 50/50 - from FAA and NTSB experimental studies.

The suggestion is to have some range so you avoid collision courses all together rather than waiting for them to happen.

Yes these are small probabilities of horrific events - but that was the whole point of Flarm in the first place. Part of the reason why stealth mode "works just fine" is that flying without Flarm works just fine even if you don't look out the window - almost all the time.

I'll surely fly in a stealth mandated contest if there is no reasonable alternative, but I've been finding the less restricted OLC/XC events pretty enjoyable too and it will certainly affect my choice of mix. That's just me. The poll would indicate more pilots are not fond of stealth than are fond of stealth.9q1

9B

[Andy Blackburn]

On Saturday, November 28, 2015 at 1:19:12 PM UTC-8, Andy Blackburn wrote:

One other perspective. I really hate getting collision alarms - particularly on course where you by definition have missed something if it happens. It generates a near-panic emotional response because you are potentially seconds from being hit. A little tunnel vision sets in as you look down to the display to try to make out the direction and relative altitude of the target and then swing your gaze to pick them up - and figure out what to do. I have on occasion picked up the wrong (farther away) glider in the same general direction - that leads to a very nasty surprise.

Flarm is architected as a multi-layer defense against collisions. The collision alarm is the last line of defense and the broader target tracking is the more important preventative layer - much the way ATC vectoring of traffic is the more important part of keeping airliners apart and TCAS is the last line of defense.

I find degrading the first line of defense and relying only on the last line of defense to not only be somewhat additionally risky because you are counting on everyone to do the right thing in a few seconds under stress, but it is also more anxiety producing to rely almost entirely on an alarm of an impending collision, rather than staying out of each other's way - even if it works out perfectly every time an alarm happens. I don't think very many people would be comfortable getting on airliners if they sent all the air traffic controllers home and relied just on TCAS - even if it worked perfectly every single time.

I know - I've totally lost my sense of excitement and adventure.

9B

[jfitch]

On Saturday, November 28, 2015 at 6:51:46 AM UTC-8, John Godfrey (QT) wrote:

>

> WRT thermals, one prior poster observed that Winpilot is excellent for displaying gliders in a thermal. The idea of someone in a thermal not looking out the window 100% of the time is troubling to me. There have been at least two instances I am personally aware of where FLARM equipped gliders have collided in a thermal.
>
> QT

WRT to tac display in thermals, I am more concerned about the gliders I cannot see, than the ones I can. The latter have already been accounted for. The former will not be seen even if I put 200% of my attention outside the cockpit. These are the ones behind or below in the circle. A poor tactical display may require too much attention to process, leading to a loss of overall situational awareness. A good one requires a 1 second glance to process everything.

[jfitch]

1/4 minute may be ample in controlled tests between two gliders. It may not be in the real world.

Imagine three gliders at 200 kph slightly separated vertically, horizontally, and longitudenally running a street, meeting 3 gliders similarly displaced on an opposite heading. This is not all that uncommon over the Whites in the west. You have 12 seconds to visually ID the three opposing gliders, account for the two with you, decide on an evasive action and implement it, all without knowing the plans of the 5 other gliders, and making further adjustments when 2 of the other 5 didn't do what you guessed. You cannot visually ID a glider head on against clouds at 2 km, hard even at 1 in a short time. Had you seen them 5 or 10 km away, the situation will not even arise since a minor adjustment would have completely eliminated the possibility.

I have argued against considering Flarm to be that much of a safety device, given that mid air collisions are quite rare. But to have it in the cockpit and then disable it in precisely the conditions most likely to cause a mid air (most of them have been in contests) is odd logic.

[jpg...@gmail.com]

There seems to be some misunderstanding and dysfunctional response to Flarm alarms being described here. When an alarm sounds look out and scan fully and quickly (including above) rather than looking at the display first. If you see no glider that appears to be on a collision course you are in the same position as you would be if you didn't have Flarm but were being really attentive to see and avoid PLUS the other glider that you can't see is also getting an alarm and he can probably see you if you can't see him. People seem to forget in theur response to alerts that Flarm is two way and we are also giving out alarms.

Local soaring for my club is many gliders on the same short ridge soaring back and forth at similar altitudes and we can get several Flarm alerts per hour on a busy day. Sometines it isn't possible to tell which glider you're sharing an alert with. I rarely look at the display in gaggles and local hill soaring and if ahead and all around and above seems clear and the then I just make a slight deviation and trust that I am in the view of the other glider. Often alerts go away without me knowing where it came from. In this scenario, as in busy thermals, we Flarm equipped pilots are far better off by having our See and Avoid continually stimulated.

The problem is gliders that don't have Flarn and we had a collision between two of those on our ridge a couple of years ago.

[Jonathan St. Cloud]

So let me understand what you are saying. You are flying along doing a scan as always and then when you get a Flarm alert you continue the same scan, only more quickly, that has not yielded any results because to glance at the screen for a position of the possible collision target would be dysfunctional? And oh, if you have not seen the collision target glider, don't worry he has probably seen you. Just beautiful.

On Saturday, November 28, 2015 at 11:41:01 PM UTC-8, jpg...@gmail.com wrote:
> There seems to be some misunderstanding and dysfunctional response to Flarm alarms being described here. When an alarm sounds look out and scan fully and quickly (including above) rather than looking at the display first. If you see no glider that appears to be on a collision course you are in the same position as you would be if you didn't have Flarm but were being really attentive to see and avoid PLUS the other glider that you can't see is also getting an alarm and he can probably see you if you can't see him. People seem to forget in theur response to alerts that Flarm is two way and we are also giving out alarms.
>

[James Metcalfe]

At 03:22 27 November 2015, jfitch wrote:
>James, if you are plagued by false alarms coming even from
the wrong
>heading, I am all the more curious. I have not had any false
alarms, perhaps
>some false negatives (probably should had been an alarm).
Never from the wrong
>direction. Do you have the IGC files from a flight in which you
remember
>that happening? It would be interesting to put it into SeeYou or
other
>software (or even look at it in a text editor) to see what the
accuracy of fix
>was. I have noticed that the Flarm GPS is typically reporting a
larger
>error, and in some cases quite large. I'm not sure what the
algorithms do with
>the precision of fix, but it seems like that is the most likely
source of
>the errors you describe. For example the Flarm IGC file from
my glider will
>show a typical precision of fix of around 3 - 4 meters, but
sometimes it
>will go up to 30-40 for unknown reasons. The Air Avionics gps
will show a
>precision of 1 - 2 meters on the same flight and might also go
up in the same
>areas but not as much. Ridge flying in the Alps you might have
the antenna
>shaded on one or more sides, which will increase the HDOP.
The precision is
>the normally the last three digits of the B record in the IGC
file. All of
>my flying is high altitude and with a clear view of the sky.

Others have now posted in more detail on the track vs. heading
errors of Flarm. These are inevitable (until wind information is
available to Flarm), and not (I’m confident) a problem with any
of the 3 installations which I have used. I’m afraid I have not
kept a log of the various incidents to which I have referred, nor
do I have the IGC files.

It seems to me that you yourself have provided the explanation
of the differences in our experiences of Flarm:
- You fly largely alone, in wide open spaces, but occasionally
meeting other gliders on the same cloud street.
- I fly mainly in a busy Alpine setting, constantly close to (and
co-operating with) other gliders on ridges and in thermals. (If I
find myself alone I am reassured that it is not just me who is
finding the conditions difficult to soar in!)
J.

[jfitch]

A diametrically opposed false alarm in a thermal suggests wind in the 30 - 60 knot range. I have not seen good thermal development in those conditions, even in extremely strong western desert conditions. I have flown in gaggles of 10 - 15 gliders near the same altitude in the same thermal and have never had such a false alarm.

[jfitch]

On Saturday, November 28, 2015 at 11:41:01 PM UTC-8, jpg...@gmail.com wrote:

Another point about tac displays and warnings vs. attention: A voice warning system eliminates any visual attention deficit, no glance it necessary. The voice warnings from the Air Avionics vario are very good. On the other hand keeping track of nearby traffic on the tactical display when they are farther away, is exactly the time you can afford the attention to it, process the information, and plan avoidance maneuvers, compared to an unexpected warning giving only a few seconds to do all of that.

[jpg...@gmail.com]

Given that Flarm is comparing predicted flight paths of the two gliders and issuing alerts based on calculations of possible conflicts up to 18 seconds ahead you would have to be certain that both gliders were flying exactly concentric circles of the same radius and speed before you could be sure that an alert from a diametrically opposed glider was a "false alarm". It would be more likely that the Flarm units were performing as designed and within their fairly large buffers 18 seconds ahead. Granted, our personal buffer zones in thermals are tighter than the those of the Flarm algorithms. As I wrote previously I have demonstrated in flight to a copilot that what he thought was a false alarm from an almost diametrically opposed glider was in fact proven to be a valid alarm about 3/4 turn later. The other glider was diametrically opposed but not flying concentrically with us.