PowerFlarm and ADS-B solution, can we find one? [Archive]

Andrzej Kobus

January 4th 16, 11:08 PM

I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
Let's try to define some criteria that might be acceptable to all:
1) Should targets be visible on PowerFlarm display?
2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
3) Do we allow for displaying altitude of another glider on PowerFlarm display?
4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
5) Do we need to be able to identify a conflicting glider?
6) What are the minimum requirements for identification of conflicting traffic?
7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
9) Anything else?

(1) I suggest "Yes" otherwise there is no situational awareness at all:
a. In my opinion some situational awareness in the vicinity is required
b. one evasive action can cause another dangerous situation
c. it is very stressful to be reacting to sudden alarms without prior awareness of where the traffic might be coming from and this can lead to development of other dangerous situations
(2) Let's do some math. Two gliders on traveling in opposite directions at 17k feet can easily be closing distance at the rate of 260 kts. Let's remember about TAS at high altitude. That is almost 500 km/hour. Let's use the 60 seconds as an adequate awareness time. This leads to a distance of 8km. If we desire to use 5km as a minimum than we have 37 seconds of advanced warning. Is that enough? Each of us will have different criteria. I think 37 seconds might be enough for me if I am rested and there is good visibility. Let's remember it is not only reaction time but also achieving meaningful separation, and knowing which way to turn and then maybe have some room for a mistake (like turning the same way for by gliders)
(3) I think I would like to know altitude difference and if traffic is climbing or descending or just altitude. I really don't care much about what the rate of change is.
(4) Answered above
(5) Initially I thought this was not required but I think being able to communicate might be important in some situations.
(6) I do not think we need contest ids we could create another way of identifying gliders, however with time people would figure out what the opponent codes are if they really wanted to.
(7) Absolutely "YES" This is where "Stealth" mode fails.
(8) I have seen power traffic cruising happily under cloud bases. That is why I have ADS-B out and I also have ADS-B In on both 1090 and 978. I get traffic from ground stations. I put the ADS-B out so I can see the power traffic around me and not to freak out every time I see a ring on PCAS not knowing where the traffic is. The only way I see we could control ADS-B in is if PowerFlarm updated its ADSB-in to include ground station transitions, which I thought they did, but maybe not. Then we could limit ADS-B traffic to 5 km, which could be a huge mistake because at 17k feet power traffic can go really fast. This is a real problem. Additional ADS-B in equipment I have in my glider to receive ground station traffic cannot be limited to 5km. I would be willing to get the other equipment out of my glider as long as I get traffic transmitting by ground stations on PF, but what to do about fast power traffic? Anyone has a good idea? Filter based on speed?
As you can see, complexity of working out a solution is huge as there are many variables. We would need to deal not only with flarm traffic but also with ADS-B traffic and consider you might deal with high speed ADS-B traffic..

Let's see if we could agree on technical specifications for future competition mode that would be acceptable to everyone, but it needs to include ADS-B in. I am not sure there is a solution, but let's try.

Let's give each other some room and that includes RC. It would also be nice to get a briefing from RC where things are with Flarm and what is being considered by Flarm. Lastly as you can see there are many variables. It would be nice if we could agree to not attempt to make any changes for 2016 and instead spend time trying to figure out what a solution should be and test it properly. Again, a solution should meaningfully deal with ADS-B.

I hope we could keep this thread focused on a solution and not question our positions. We have done enough of that.

[email protected]

January 4th 16, 11:48 PM

On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:

> (8) I have seen power traffic cruising happily under cloud bases. That is why I have ADS-B out and I also have ADS-B In on both 1090 and 978. I get traffic from ground stations. I put the ADS-B out so I can see the power traffic around me and not to freak out every time I see a ring on PCAS not knowing where the traffic is. The only way I see we could control ADS-B in is if PowerFlarm updated its ADSB-in to include ground station transitions, which I thought they did, but maybe not. Then we could limit ADS-B traffic to 5 km, which could be a huge mistake because at 17k feet power traffic can go really fast. This is a real problem. Additional ADS-B in equipment I have in my glider to receive ground station traffic cannot be limited to 5km. I would be willing to get the other equipment out of my glider as long as I get traffic transmitting by ground stations on PF, but what to do about fast power traffic? Anyone has a good idea? Filter based on speed?
> As you can see, complexity of working out a solution is huge as there are many variables. We would need to deal not only with flarm traffic but also with ADS-B traffic and consider you might deal with high speed ADS-B traffic.
>

What ADS-B "in/out" transceiver do you use?

What hardware do you use to display the ADS-B "in" traffic and weather information?

Andrzej Kobus

January 4th 16, 11:54 PM

On Monday, January 4, 2016 at 6:48:41 PM UTC-5, wrote:
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>
> > (8) I have seen power traffic cruising happily under cloud bases. That is why I have ADS-B out and I also have ADS-B In on both 1090 and 978. I get traffic from ground stations. I put the ADS-B out so I can see the power traffic around me and not to freak out every time I see a ring on PCAS not knowing where the traffic is. The only way I see we could control ADS-B in is if PowerFlarm updated its ADSB-in to include ground station transitions, which I thought they did, but maybe not. Then we could limit ADS-B traffic to 5 km, which could be a huge mistake because at 17k feet power traffic can go really fast. This is a real problem. Additional ADS-B in equipment I have in my glider to receive ground station traffic cannot be limited to 5km. I would be willing to get the other equipment out of my glider as long as I get traffic transmitting by ground stations on PF, but what to do about fast power traffic? Anyone has a good idea? Filter based on speed?
> > As you can see, complexity of working out a solution is huge as there are many variables. We would need to deal not only with flarm traffic but also with ADS-B traffic and consider you might deal with high speed ADS-B traffic.
> >
>
> What ADS-B "in/out" transceiver do you use?
>
> What hardware do you use to display the ADS-B "in" traffic and weather information?

FreeFlight 1201 over Trig 22 and Stratus 2s with ForeFlight on iPhone 6s Plus. For contest only 1090 receiver and ForeFlight on iPhone 6s Plus so I do not get accused of using in flight weather.

smfidler

January 5th 16, 02:20 AM

Good thought process Andrzej!

Agree climb rates are useless and cause a great deal of the insecurity about Flarm. It also provides little situational awareness value (safety). Only realtive altitude matters (+100, -500, +1000, etc).

But in general location of all objects in the air that could potentially kill me, or I them, I want to be able to detect, with a huge margin of safety error, as coverage is not 100% (never will be for Flarm) and they are not mandatory (never will be after this debate).

Sean

January 5th 16, 07:03 AM

What if FLARM were to integrate with ADS-B out. This box would use the existing FLARM technology to determine conflicts and to display proximate targets with other FLARM equipped gliders and not use that glider's ADS-B signal.. FLARM is better for glider to glider collision avoidance. If the glider got out of FLARM range the box would automatically start using the ABS-B technology. The display of this glider might change to a different color on the display as is goes to ADS-B. All aircraft with ADS-B and no FLARM would be displayed all the time at any selected range.

Okay, I know that there are technical difficulties and enforcement issues. Here's the question:

Would a competition mode that allows unlimited range and just doesn't display FLARM equipped gliders that are more +/-1000 difference in altitude be acceptable? If you need +/- 1500 ft okay.

Again, outside of FLARM range (6-10 sm) ADS-B picks up and displays everything for this glider. Non-participants with ADS-B, especially powered traffic is always shown.

Technical issues aside for now, doesn't this give plenty of collision avoidance and also work as a competition mode.

XC

[email protected]

January 5th 16, 02:02 PM

On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> Let's try to define some criteria that might be acceptable to all:
> 1) Should targets be visible on PowerFlarm display?
> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> 5) Do we need to be able to identify a conflicting glider?
> 6) What are the minimum requirements for identification of conflicting traffic?
> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> 9) Anything else?
>
>
In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
1- Yes
2- I have suggested 5km previously
3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
4 No
5- Yes if it is an identified conflict.
6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
Again- Thanks for fostering a constructive exchange.
UH

jfitch

January 5th 16, 05:14 PM

On Tuesday, January 5, 2016 at 6:02:51 AM UTC-8, wrote:
<SNIP>> Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant.

I don't believe that is correct. All the information on stealth mode (actually named PRIV in the documents) suggests that the implementation is on the receive end. When the PRIV flag is set, the broadcasts contain the same information, but are marked with the PRIV flag, telling the receiver not to forward the information to the serial port for display (regardless of display). Since the receivers are also running Flarm firmware, they respect this flag. The information is there for the hacking today by someone determined enough. All that needs to be done for non-contestants is to allow the receiver to make the decision based on its PRIV flag. If I was not flying in the contest and did not have the PRIV flag set, my receiver would forward the information to the serial port and the display. The vulnerability to cheating and hacking is the same as now. The change to the firmware to do this should be trivial.

From the dataport spec: "The stealth flag indicates whether the own broadcasted data shall be solely used for collision avoidance15, i.e. where not all the received information is forwarded to the serial data-port and therefore is not available to external, graphical displays or PDA's to prevent abuse in competitions."

jfitch

January 5th 16, 05:36 PM

Since the paranoia seems to surround the theoretical possibility of Flarm leeching, here is a suggestion: I believe you may be able to determine leeching (provided someone can define it) by using the Flarm IGC file. In it are comment lines which enumerate each Flarm contact. I'm not sure if I am decoding these correctly but it seems as though the received Flarm is identified uniquely. To leech in the way that is the source of the paranoia, one would need to keep in Flarm contact throughout the day. This should be quite apparent from an analysis of the contact comments, perhaps in combination with the position reports to see who is leading and who trailing. Some definition of leeching would need to be proposed based on leading/following, % time in contact, etc. There is no information there that is not already contained in the relevant IGC position data, but it is easier to process, and adds proof that the target of the leech was in Flarm contact (which must be part of any Flarm leeching by definition).

Note that the same thing can be done for ADS-B, at least with Mode S transponders and a PowerFlarm log. It would flag visual leeching as well, since visual leeching is a subset of Flarm leeching.

All this appears to be technically feasible, except perhaps for the definition of leeching which has so far been elusive. The log checking can be an automated part of the scoring process, or applied in the event of a protest.

[email protected]

January 5th 16, 08:10 PM

On Tuesday, January 5, 2016 at 12:14:30 PM UTC-5, jfitch wrote:
> On Tuesday, January 5, 2016 at 6:02:51 AM UTC-8, wrote:
> <SNIP>> Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant.
>
> I don't believe that is correct. All the information on stealth mode (actually named PRIV in the documents) suggests that the implementation is on the receive end. When the PRIV flag is set, the broadcasts contain the same information, but are marked with the PRIV flag, telling the receiver not to forward the information to the serial port for display (regardless of display). Since the receivers are also running Flarm firmware, they respect this flag. The information is there for the hacking today by someone determined enough. All that needs to be done for non-contestants is to allow the receiver to make the decision based on its PRIV flag. If I was not flying in the contest and did not have the PRIV flag set, my receiver would forward the information to the serial port and the display. The vulnerability to cheating and hacking is the same as now. The change to the firmware to do this should be trivial.
>
> From the dataport spec: "The stealth flag indicates whether the own broadcasted data shall be solely used for collision avoidance15, i.e. where not all the received information is forwarded to the serial data-port and therefore is not available to external, graphical displays or PDA's to prevent abuse in competitions."

From Flarm card:
Stealth Mode
The data FLARM(R)
receives from other is available at the serial
port to external devices like PDA's or graphical displays which
can thus display the nearby environment in detail. While this
information is useful for you, you might not want your
competitors to make use of this information, and others might
have the similar asymmetrical preferences. With the stealth
mode (named 'Privacy' before) in FLARM(R)
, you can choose
the trade-off acceptable for you between two modes:
* 'Stealth Mode' unchecked: you have full access to the data
you receive from others with Stealth Mode disabled and,
and others have full access to the data you send about
yourself if they have Stealth Mode disabled, or
* 'Stealth Mode' checked: you have limited access to the
data you receive from others and, and others have limited
access to the data you send about yourself independent of
their Stealth Mode setting.

I interpret this as saying info out to others is limited in Stealth mode which is the basis for my comment. I originally thought filtering was only on the receiving side which as you said, but this information contradicts that. I think I stand by my comment.
UH

Tango Eight

January 5th 16, 08:21 PM

On Tuesday, January 5, 2016 at 12:36:54 PM UTC-5, jfitch wrote:
> Since the paranoia[...]

Can we please have just one flarm-in-competition thread that is constructive? Enough of the loaded comments, goading and scare mongering!

UH: all filtering occurs on receiving end. It has to be this way, else anti-collision warning performance would be compromised.

T8

[email protected]

January 5th 16, 08:42 PM

On Tuesday, January 5, 2016 at 3:21:30 PM UTC-5, Tango Eight wrote:
> On Tuesday, January 5, 2016 at 12:36:54 PM UTC-5, jfitch wrote:
> > Since the paranoia[...]
>
> Can we please have just one flarm-in-competition thread that is constructive? Enough of the loaded comments, goading and scare mongering!
>
> UH: all filtering occurs on receiving end. It has to be this way, else anti-collision warning performance would be compromised.
>
> T8

Does the Flarm info I showed above not disagree with what you just stated?, and if not, please help me understand why.
Additionally, if info out is not changed, why does my use of Stealth affect what others not using Stealth see related to me?
Thx
UH

Luke Szczepaniak

January 5th 16, 09:14 PM

> Additionally, if info out is not changed, why does my use of Stealth affect what others not using Stealth see related to me?

If your FLARM is set to STEALTH it will not show all the info it receives on your display regardless of source. The STEALTH FLARM sends a message out telling other FLARM units that you are in STEALTH. When another unit sees this as part of the message it will not display your information on their own display.

Luke Szczepaniak

Andrzej Kobus

January 5th 16, 10:56 PM

On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
> > I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> > Let's try to define some criteria that might be acceptable to all:
> > 1) Should targets be visible on PowerFlarm display?
> > 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> > 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> > 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> > 5) Do we need to be able to identify a conflicting glider?
> > 6) What are the minimum requirements for identification of conflicting traffic?
> > 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> > 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> > 9) Anything else?
> >
> >
> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
> 1- Yes
> 2- I have suggested 5km previously
> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
> 4 No
> 5- Yes if it is an identified conflict.
> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
> Again- Thanks for fostering a constructive exchange.
> UH

I think we can find a common ground on a number of points:
(1), (2), (4), (5), (6), (7)
In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
Let's consider this closely:
We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.

The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.

Let's consider an edge case both gliders change altitude 10 m/s each, quite possible in western conditions. This gives you 20 m/s combined vertical closure speed. If you want to obtain reaction time of 37 seconds (same as for the 5 km distance) you need 720 meters of separation. That means you need to be able to see traffic that is either 2000 feet above you or below you (I rounded the number down). Of course any lower number would be problematic.. I hope you agree with this reasoning.

Now the hard part (8), the information that ADS-B provides can be utilized to show whatever one wants with the right smart phone software. The only way to restrict that would be to run approved displays. In the USA however all ADS-B in solutions that are useful are provided by companies that have nothing to do with gliding.

One option I see is that PowerFlarm upgrades software of their unit to ensure proper reception of ground station information (if there is enough processing power within the unit to deal with both ground station broadcast and Flarm functions). Then display manufacturers could filter traffic the same way as they would do for gliders. With the exception of traffic moving faster than e.g. 150 kts where no filtering would take place. That leaves us with a case where there is not enough ground station coverage (west) and where 978 Mhz band is useful to identify traffic equipped with ADS-B out UAT. Maybe PF units could be upgraded, difficult to say.

Maybe a better solution would be for someone e.g. LXNav or Flarm to create a receiver for both 1090 Mhz and 978 Mhz frequencies that could be configured to restrict output in the same way as with the new mode that we described above.

This is a tough nut to crack and it also limits choices for buyers so a solution would need to be very well priced. An open source project is another opportunity but it would require someone to start it and push forward. The hardware is there but there is still a problem integrating the devices to common display. This is doable but not simple, especially for the market of our size. Although ADS-B In solution that is well priced might be something that many more pilots could get interested in.

Let's keep this thread technical.

jfitch

January 5th 16, 11:26 PM

On Tuesday, January 5, 2016 at 12:10:14 PM UTC-8, wrote:
> On Tuesday, January 5, 2016 at 12:14:30 PM UTC-5, jfitch wrote:
> > On Tuesday, January 5, 2016 at 6:02:51 AM UTC-8, wrote:
> > <SNIP>> Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant.
> >
> > I don't believe that is correct. All the information on stealth mode (actually named PRIV in the documents) suggests that the implementation is on the receive end. When the PRIV flag is set, the broadcasts contain the same information, but are marked with the PRIV flag, telling the receiver not to forward the information to the serial port for display (regardless of display). Since the receivers are also running Flarm firmware, they respect this flag. The information is there for the hacking today by someone determined enough. All that needs to be done for non-contestants is to allow the receiver to make the decision based on its PRIV flag. If I was not flying in the contest and did not have the PRIV flag set, my receiver would forward the information to the serial port and the display. The vulnerability to cheating and hacking is the same as now. The change to the firmware to do this should be trivial.
> >
> > From the dataport spec: "The stealth flag indicates whether the own broadcasted data shall be solely used for collision avoidance15, i.e. where not all the received information is forwarded to the serial data-port and therefore is not available to external, graphical displays or PDA's to prevent abuse in competitions."
>
>
> From Flarm card:
> Stealth Mode
> The data FLARM(R)
> receives from other is available at the serial
> port to external devices like PDA's or graphical displays which
> can thus display the nearby environment in detail. While this
> information is useful for you, you might not want your
> competitors to make use of this information, and others might
> have the similar asymmetrical preferences. With the stealth
> mode (named 'Privacy' before) in FLARM(R)
> , you can choose
> the trade-off acceptable for you between two modes:
> * 'Stealth Mode' unchecked: you have full access to the data
> you receive from others with Stealth Mode disabled and,
> and others have full access to the data you send about
> yourself if they have Stealth Mode disabled, or
> * 'Stealth Mode' checked: you have limited access to the
> data you receive from others and, and others have limited
> access to the data you send about yourself independent of
> their Stealth Mode setting.
>
> I interpret this as saying info out to others is limited in Stealth mode which is the basis for my comment. I originally thought filtering was only on the receiving side which as you said, but this information contradicts that. I think I stand by my comment.
> UH

The sending unit must always send all the data, and the receiving unit receive it. Otherwise how will they determine if a conflict exists? Stealth only decides if the data will be forwarded to the serial port out for display, otherwise it is held sequestered in the box. I don't see anything in what you quoted that contradicts this. However someone knows, and could clarify this finally.

Andy Blackburn[_3_]

January 6th 16, 02:14 AM

On Tuesday, January 5, 2016 at 6:02:51 AM UTC-8, wrote:
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
> > I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> > Let's try to define some criteria that might be acceptable to all:
> > 1) Should targets be visible on PowerFlarm display?
> > 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> > 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> > 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> > 5) Do we need to be able to identify a conflicting glider?
> > 6) What are the minimum requirements for identification of conflicting traffic?
> > 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> > 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> > 9) Anything else?
> >
> >
> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
> 1- Yes
> 2- I have suggested 5km previously
> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
> 4 No
> 5- Yes if it is an identified conflict.
> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
> Again- Thanks for fostering a constructive exchange.
> UH

Andrzej must build bridges for a living.

Replying to two different topics raised in this thread.

1) Yes
2) I'd consider 5km bare minimum as the "Situational Awareness Crowd" out west will be heads down more frequently street-running with as little as 35-40 seconds of forward visibility - scanning the screen every 20 seconds is a bit high. It would be preferable to have a bit more.
3,4) Relative altitude +/-750 meters - high altitude zooms and pushes are a lot more than 200m when done in opposition - plus opposite lift/sink. Having someone pop into your SA zone from below right when you are rolling out of a thermal and pushing over - hard to deal with.
5,6) Flarm ID plus FlarmNet ID if available for conflicts. Flam ID is next to useless for making contact for converging multi-ship situations - if having stealth allow us to require FlarmNet for safety reasons, so much the better.
7) This can't be allowed in any future incarnation of stealth - too much other traffic want 5 mile separation and can be coming in a lot hotter than glider speeds if it gets deployed in jets (mostly a European/UK issue for now - but it's one code base). Also, subjecting the uninitiated to Stealth mode without their knowledge or any briefing is a really bad idea - among other things it makes it harder to stay out of the way of the gaggle, etc.
8) Honestly I think ADS-B is hopeless in terms of implementing any kind of stealth mode. It would involve trying to coordinate the efforts of too many OEMs, may have regulatory implications if the glider exemption falls (as it seems likely to), won't deal with TIS-B Mode C traffic at all and might require burdensome racing-only approved equipment lists. Plus unless the exact Flarm algorithm is used on a combined dataset of ADS-B plus Flarm traffic you'll never be able to dedup the traffic leading to ghosting, multiple alarms - makes my head spin. Ultimately, ADS-B puts an end to any practical stealth implementation without draconian equipment restrictions and intractable technical difficulties - and is even more certain with an end to the glider exemption for transponders and/or ADS-B Out.

I am 99.9% certain that it is impossible for Flarm Stealth to be implemented on the transmit side. IIRC, part of the collision algorithm involves projected position estimates performed on the transmit side and sent to all receivers for comparison with each internal projected position. You can't perform collision warning without this information and stealth would cut it out if done pre-transmission. Without a way to estimate whether a target is a collision conflict to pass it through to the collision display you need both received and local position estimates. Since the Flarm documentation clearly states that alarms can be generated outside the stealth 2km traffic radius it's just logically impossible for this to happen based on data that is cut off before being transmitted.

If you want to chase your tail logically, ask yourself if position data could be transmitted only for collision threats but not for non-threats. Answer: What if everybody did that?

BTW, someone needs to confirm how far out Flarm projects future position for collision warning - I thought I remembered 15 seconds from some conversation. If so, that would presumably be the maximum collision threat advanced warning you'd get under stealth unless you had more range on the traffic display side.

9B

Dan Marotta

January 6th 16, 03:36 PM

In the spirit of technical discussion I must point out what seems to me
to be a basic flaw in logic.

The statement that you can gain or lose altitude at 10 m/s (~20 kt) is
certainly valid in the US southwest. However the supposition that two
gliders traveling in opposite directions with 200 meter vertical
separation would be at risk of collision due to one suddenly dropping
and the other suddenly climbing /_in the same airmass_/ does not appear
to be a serious risk. To do this would require one or both of the
gliders to pull up in sink or push over in lift. In reality both would
either pull up or push over thus keeping the vertical separation nearly
the same.

As to the stealth argument, if only ID and (claimed) climb rate are
masked, with position and relative altitude still displayed, where's the
loss in situational awareness? Remember that there are still right of
way rules to follow to avoid swapping paint.

Someone mentioned the danger of one glider pushing over to leave a
thermal as another is pulling up into the same thermal. This is a valid
concern, though a special case. Assuming both aircraft are equipped
with some sort of anti-collision device then a maintained situational
awareness should preclude any abrupt maneuvers in close proximity to
another glider. I realize that some folks have a "get out of my way"
philosophy and no device can be expected to keep them from doing
something unexpected.

On 1/5/2016 3:56 PM, Andrzej Kobus wrote:
> On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
>> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>>> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
>>> Let's try to define some criteria that might be acceptable to all:
>>> 1) Should targets be visible on PowerFlarm display?
>>> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
>>> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
>>> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
>>> 5) Do we need to be able to identify a conflicting glider?
>>> 6) What are the minimum requirements for identification of conflicting traffic?
>>> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
>>> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
>>> 9) Anything else?
>>>
>>>
>> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
>> 1- Yes
>> 2- I have suggested 5km previously
>> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
>> 4 No
>> 5- Yes if it is an identified conflict.
>> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
>> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
>> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
>> Again- Thanks for fostering a constructive exchange.
>> UH
> I think we can find a common ground on a number of points:
> (1), (2), (4), (5), (6), (7)
> In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
> Let's consider this closely:
> We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.
>
> The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.
>
> Let's consider an edge case both gliders change altitude 10 m/s each, quite possible in western conditions. This gives you 20 m/s combined vertical closure speed. If you want to obtain reaction time of 37 seconds (same as for the 5 km distance) you need 720 meters of separation. That means you need to be able to see traffic that is either 2000 feet above you or below you (I rounded the number down). Of course any lower number would be problematic. I hope you agree with this reasoning.
>
> Now the hard part (8), the information that ADS-B provides can be utilized to show whatever one wants with the right smart phone software. The only way to restrict that would be to run approved displays. In the USA however all ADS-B in solutions that are useful are provided by companies that have nothing to do with gliding.
>
> One option I see is that PowerFlarm upgrades software of their unit to ensure proper reception of ground station information (if there is enough processing power within the unit to deal with both ground station broadcast and Flarm functions). Then display manufacturers could filter traffic the same way as they would do for gliders. With the exception of traffic moving faster than e.g. 150 kts where no filtering would take place. That leaves us with a case where there is not enough ground station coverage (west) and where 978 Mhz band is useful to identify traffic equipped with ADS-B out UAT. Maybe PF units could be upgraded, difficult to say.
>
> Maybe a better solution would be for someone e.g. LXNav or Flarm to create a receiver for both 1090 Mhz and 978 Mhz frequencies that could be configured to restrict output in the same way as with the new mode that we described above.
>
> This is a tough nut to crack and it also limits choices for buyers so a solution would need to be very well priced. An open source project is another opportunity but it would require someone to start it and push forward. The hardware is there but there is still a problem integrating the devices to common display. This is doable but not simple, especially for the market of our size. Although ADS-B In solution that is well priced might be something that many more pilots could get interested in.
>
> Let's keep this thread technical.
>
>

--
Dan, 5J

jfitch

January 6th 16, 05:13 PM

On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
> In the spirit of technical discussion I must point out what seems to
> me to be a basic flaw in logic.
>
>
>
> The statement that you can gain or lose altitude at 10 m/s (~20 kt)
> is certainly valid in the US southwest.* However the supposition
> that two gliders traveling in opposite directions with 200 meter
> vertical separation would be at risk of collision due to one
> suddenly dropping and the other suddenly climbing in the same
> airmass does not appear to be a serious risk.* To do
> this would require one or both of the gliders to pull up in sink or
> push over in lift.* In reality both would either pull up or push
> over thus keeping the vertical separation nearly the same.
>
>
>
> As to the stealth argument, if only ID and (claimed) climb rate are
> masked, with position and relative altitude still displayed, where's
> the loss in situational awareness?* Remember that there are still
> right of way rules to follow to avoid swapping paint.
>
>
>
> Someone mentioned the danger of one glider pushing over to leave a
> thermal as another is pulling up into the same thermal.* This is a
> valid concern, though a special case.* Assuming both aircraft are
> equipped with some sort of anti-collision device then a maintained
> situational awareness should preclude any abrupt maneuvers in close
> proximity to another glider.* I realize that some folks have a "get
> out of my way" philosophy and no device can be expected to keep them
> from doing something unexpected.
>
>
>
>
> On 1/5/2016 3:56 PM, Andrzej Kobus
> wrote:
>
>
>
> On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
>
>
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>
>
> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> Let's try to define some criteria that might be acceptable to all:
> 1) Should targets be visible on PowerFlarm display?
> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> 5) Do we need to be able to identify a conflicting glider?
> 6) What are the minimum requirements for identification of conflicting traffic?
> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> 9) Anything else?
>
>
>
>
> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
> 1- Yes
> 2- I have suggested 5km previously
> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
> 4 No
> 5- Yes if it is an identified conflict.
> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
> Again- Thanks for fostering a constructive exchange.
> UH
>
>
> I think we can find a common ground on a number of points:
> (1), (2), (4), (5), (6), (7)
> In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
> Let's consider this closely:
> We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.
>
> The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.

Dan Marotta

January 6th 16, 08:03 PM

Protocol - it's there for a reason. I understand coordinating in a
thermal, e.g., "BD, I'm inside your turn at 5 o'clock low", but calling
someone almost a mile away and suggesting that he make a turn so as not
to collide with me when I can simply make my own turn doesn't make sense.

Do you really need information on another aircraft within 300 meters
vertical spacing from you? That's almost 1000 feet! IFR and VFR
traffic routinely pass each other head on, over taking, and at oblique
angles with only 152 meters (500') vertical separation. I can
understand your concerns in and around thermals, but not in cruise.

On 1/6/2016 10:13 AM, jfitch wrote:
> On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
>> In the spirit of technical discussion I must point out what seems to
>> me to be a basic flaw in logic.
>>
>>
>>
>> The statement that you can gain or lose altitude at 10 m/s (~20 kt)
>> is certainly valid in the US southwest. However the supposition
>> that two gliders traveling in opposite directions with 200 meter
>> vertical separation would be at risk of collision due to one
>> suddenly dropping and the other suddenly climbing in the same
>> airmass does not appear to be a serious risk. To do
>> this would require one or both of the gliders to pull up in sink or
>> push over in lift. In reality both would either pull up or push
>> over thus keeping the vertical separation nearly the same.
>>
>>
>>
>> As to the stealth argument, if only ID and (claimed) climb rate are
>> masked, with position and relative altitude still displayed, where's
>> the loss in situational awareness? Remember that there are still
>> right of way rules to follow to avoid swapping paint.
>>
>>
>>
>> Someone mentioned the danger of one glider pushing over to leave a
>> thermal as another is pulling up into the same thermal. This is a
>> valid concern, though a special case. Assuming both aircraft are
>> equipped with some sort of anti-collision device then a maintained
>> situational awareness should preclude any abrupt maneuvers in close
>> proximity to another glider. I realize that some folks have a "get
>> out of my way" philosophy and no device can be expected to keep them
>> from doing something unexpected.
>>
>>
>>
>>
>> On 1/5/2016 3:56 PM, Andrzej Kobus
>> wrote:
>>
>>
>>
>> On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
>>
>>
>> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>>
>>
>> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
>> Let's try to define some criteria that might be acceptable to all:
>> 1) Should targets be visible on PowerFlarm display?
>> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
>> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
>> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
>> 5) Do we need to be able to identify a conflicting glider?
>> 6) What are the minimum requirements for identification of conflicting traffic?
>> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
>> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
>> 9) Anything else?
>>
>>
>>
>>
>> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
>> 1- Yes
>> 2- I have suggested 5km previously
>> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
>> 4 No
>> 5- Yes if it is an identified conflict.
>> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
>> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
>> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
>> Again- Thanks for fostering a constructive exchange.
>> UH
>>
>>
>> I think we can find a common ground on a number of points:
>> (1), (2), (4), (5), (6), (7)
>> In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
>> Let's consider this closely:
>> We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.
>>
>> The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.
>>
>> Let's consider an edge case both gliders change altitude 10 m/s each, quite possible in western conditions. This gives you 20 m/s combined vertical closure speed. If you want to obtain reaction time of 37 seconds (same as for the 5 km distance) you need 720 meters of separation. That means you need to be able to see traffic that is either 2000 feet above you or below you (I rounded the number down). Of course any lower number would be problematic. I hope you agree with this reasoning.
>>
>> Now the hard part (8), the information that ADS-B provides can be utilized to show whatever one wants with the right smart phone software. The only way to restrict that would be to run approved displays. In the USA however all ADS-B in solutions that are useful are provided by companies that have nothing to do with gliding.
>>
>> One option I see is that PowerFlarm upgrades software of their unit to ensure proper reception of ground station information (if there is enough processing power within the unit to deal with both ground station broadcast and Flarm functions). Then display manufacturers could filter traffic the same way as they would do for gliders. With the exception of traffic moving faster than e.g. 150 kts where no filtering would take place. That leaves us with a case where there is not enough ground station coverage (west) and where 978 Mhz band is useful to identify traffic equipped with ADS-B out UAT. Maybe PF units could be upgraded, difficult to say.
>>
>> Maybe a better solution would be for someone e.g. LXNav or Flarm to create a receiver for both 1090 Mhz and 978 Mhz frequencies that could be configured to restrict output in the same way as with the new mode that we described above.
>>
>> This is a tough nut to crack and it also limits choices for buyers so a solution would need to be very well priced. An open source project is another opportunity but it would require someone to start it and push forward. The hardware is there but there is still a problem integrating the devices to common display. This is doable but not simple, especially for the market of our size. Although ADS-B In solution that is well priced might be something that many more pilots could get interested in.
>>
>> Let's keep this thread technical.
>>
>>
>>
>>
>>
>>
>>
>> --
>>
>> Dan, 5J
> Climb rate is already effectively masked by Flarm, since it is so wildly inaccurate as to be fantasy. ID masking eliminates the possibility of calling the other glider, and this is most useful at longer range. You are not going to reliably call another glider, receive a response, negotiate a passing protocol, then execute it in 10 seconds. But if something has to be done, then in my view climb rates could go easily (they do not really exist now, so that is a no op). The next thing I would miss least is relative altitude, if greater than (pick a number). That potentially carries tactical information. If they are within 300 meters altitude or so I would like to know, for situational awareness. Contest ID, is useful at 60+ seconds out to discuss intentions (though I do this rarely with good situational awareness) ID is useful close in to match alerts/warnings with sailplanes, when the sky is crowded. For example flying in a thermal with 3 other gliders I may get (expected) alerts about them. If a 4th joins, I might mistake an alert from it for an expected one (the false positive test problem) - but would not if all are displayed and identified on screen. Still I would see 4 gliders instead of the previous 3, so to a great extent SA is preserved.

--
Dan, 5J

jfitch

January 6th 16, 10:55 PM

On Wednesday, January 6, 2016 at 12:03:56 PM UTC-8, Dan Marotta wrote:
> Protocol - it's there for a reason.* I understand coordinating in a
> thermal, e.g., "BD, I'm inside your turn at 5 o'clock low", but
> calling someone almost a mile away and suggesting that he make a
> turn so as not to collide with me when I can simply make my own turn
> doesn't make sense.
>
>
>
> Do you really need information on another aircraft within 300 meters
> vertical spacing from you?* That's almost 1000 feet!* IFR and VFR
> traffic routinely pass each other head on, over taking, and at
> oblique angles with only 152 meters (500') vertical separation.* I
> can understand your concerns in and around thermals, but not in
> cruise.
>
>
>
>
>
>
> On 1/6/2016 10:13 AM, jfitch wrote:
>
>
>
> On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
>
>
> In the spirit of technical discussion I must point out what seems to
> me to be a basic flaw in logic.
>
>
>
> The statement that you can gain or lose altitude at 10 m/s (~20 kt)
> is certainly valid in the US southwest.* However the supposition
> that two gliders traveling in opposite directions with 200 meter
> vertical separation would be at risk of collision due to one
> suddenly dropping and the other suddenly climbing in the same
> airmass does not appear to be a serious risk.* To do
> this would require one or both of the gliders to pull up in sink or
> push over in lift.* In reality both would either pull up or push
> over thus keeping the vertical separation nearly the same.
>
>
>
> As to the stealth argument, if only ID and (claimed) climb rate are
> masked, with position and relative altitude still displayed, where's
> the loss in situational awareness?* Remember that there are still
> right of way rules to follow to avoid swapping paint.
>
>
>
> Someone mentioned the danger of one glider pushing over to leave a
> thermal as another is pulling up into the same thermal.* This is a
> valid concern, though a special case.* Assuming both aircraft are
> equipped with some sort of anti-collision device then a maintained
> situational awareness should preclude any abrupt maneuvers in close
> proximity to another glider.* I realize that some folks have a "get
> out of my way" philosophy and no device can be expected to keep them
> from doing something unexpected.
>
>
>
>
> On 1/5/2016 3:56 PM, Andrzej Kobus
> wrote:
>
>
>
> On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
>
>
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>
>
> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> Let's try to define some criteria that might be acceptable to all:
> 1) Should targets be visible on PowerFlarm display?
> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> 5) Do we need to be able to identify a conflicting glider?
> 6) What are the minimum requirements for identification of conflicting traffic?
> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> 9) Anything else?
>
>
>
>
> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
> 1- Yes
> 2- I have suggested 5km previously
> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
> 4 No
> 5- Yes if it is an identified conflict.
> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
> Again- Thanks for fostering a constructive exchange.
> UH
>
>
> I think we can find a common ground on a number of points:
> (1), (2), (4), (5), (6), (7)
> In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
> Let's consider this closely:
> We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.
>
> The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.

January 6th 16, 11:09 PM

On Wednesday, January 6, 2016 at 3:03:56 PM UTC-5, Dan Marotta wrote:
> Protocol - it's there for a reason.* I understand coordinating in a
> thermal, e.g., "BD, I'm inside your turn at 5 o'clock low", but
> calling someone almost a mile away and suggesting that he make a
> turn so as not to collide with me when I can simply make my own turn
> doesn't make sense.
>
>
>
> Do you really need information on another aircraft within 300 meters
> vertical spacing from you?* That's almost 1000 feet!* IFR and VFR
> traffic routinely pass each other head on, over taking, and at
> oblique angles with only 152 meters (500') vertical separation.* I
> can understand your concerns in and around thermals, but not in
> cruise.
>
>
>
>
>
>
> On 1/6/2016 10:13 AM, jfitch wrote:
>
>
>
> On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
>
>
> In the spirit of technical discussion I must point out what seems to
> me to be a basic flaw in logic.
>
>
>
> The statement that you can gain or lose altitude at 10 m/s (~20 kt)
> is certainly valid in the US southwest.* However the supposition
> that two gliders traveling in opposite directions with 200 meter
> vertical separation would be at risk of collision due to one
> suddenly dropping and the other suddenly climbing in the same
> airmass does not appear to be a serious risk.* To do
> this would require one or both of the gliders to pull up in sink or
> push over in lift.* In reality both would either pull up or push
> over thus keeping the vertical separation nearly the same.
>
>
>
> As to the stealth argument, if only ID and (claimed) climb rate are
> masked, with position and relative altitude still displayed, where's
> the loss in situational awareness?* Remember that there are still
> right of way rules to follow to avoid swapping paint.
>
>
>
> Someone mentioned the danger of one glider pushing over to leave a
> thermal as another is pulling up into the same thermal.* This is a
> valid concern, though a special case.* Assuming both aircraft are
> equipped with some sort of anti-collision device then a maintained
> situational awareness should preclude any abrupt maneuvers in close
> proximity to another glider.* I realize that some folks have a "get
> out of my way" philosophy and no device can be expected to keep them
> from doing something unexpected.
>
>
>
>
> On 1/5/2016 3:56 PM, Andrzej Kobus
> wrote:
>
>
>
> On Tuesday, January 5, 2016 at 9:02:51 AM UTC-5, wrote:
>
>
> On Monday, January 4, 2016 at 6:08:40 PM UTC-5, Andrzej Kobus wrote:
>
>
> I think it is time to end this back and forth ping pong about restricting the use of PF. We have to agree to disagree and try to come up with a solution that could work for both groups.
> Let's try to define some criteria that might be acceptable to all:
> 1) Should targets be visible on PowerFlarm display?
> 2) If (1) is "Yes" then what is the desired distance at which targets should be visible on PowerFlarm display?
> 3) Do we allow for displaying altitude of another glider on PowerFlarm display?
> 4) Do we allow for displaying information pertaining to climb rate or simply indicate if a glider is ascending or descending?
> 5) Do we need to be able to identify a conflicting glider?
> 6) What are the minimum requirements for identification of conflicting traffic?
> 7) Should we aim not to degrade PF functions for non-contest participating PF users in the area of a contest?
> 8) How do we deal with ADS-B in a glider? I have ADS-B out plus I have ADS-B in on both 1090 and 978.
> 9) Anything else?
>
>
>
>
> In the interest of having a constructive discussion on the topic- THANK YOU ANDRZEJ!, I will provide my personal opinions.
> 1- Yes
> 2- I have suggested 5km previously
> 3- Relative altitude only, with limit of 200meters(admittedly somewhat arbitrary)
> 4 No
> 5- Yes if it is an identified conflict.
> 6- Provide whatever ID the other glider is using. With ID's suppressed for tactical purposes, I think more pilots would be likely to make them available for conflict resolution.
> 7- Yes. To me this is the greatest shortcoming of existing Stealth. This is a double sided problem to solve. Plus- it provides little if any degradation of safety for other stake holders. This factor was the principle reason why the BGA stopped the Stealth mandate over there. Negative- it is much harder to ensure that the new mode performs equally for all without hackers turning it wide open again. This would require use of flight displays running programs shown to be compliant. Nothing is without complication. The other negative is that it could enable ground tracking . Possibly the privacy settings could prevent this.
> 8- I don't have enough visibility into how effective ADSB information will be tactically compared to Flarm to have an opinion. From a tactical point of view, I'd love it to be not there at all. From a safety point of view, I'd like it to be effective.
> Again- Thanks for fostering a constructive exchange.
> UH
>
>
> I think we can find a common ground on a number of points:
> (1), (2), (4), (5), (6), (7)
> In regards to (3) I would suggest we increase the 200 meters and this is why. Flying in Ely, NV I learned that I can gain or lose 200 meters is just 20 seconds flying straight. I almost busted class A once.
> Let's consider this closely:
> We have two gliders flying in opposite directions. One glider gains altitude the other loses altitude. The other glider may all of the sudden appear on your display say 1 km in front of you with 200 meters of vertical separation (very difficult to see). You would be left with just 10 seconds to avoid collision.
>
> The 5 km of horizontal distance gives us about 37 seconds of warning. We need to come up with the same 37 seconds of warnings for vertical separation.

Jonathan St. Cloud

January 7th 16, 12:16 AM

Dan Marotta

January 7th 16, 04:25 PM

You are correct. I do not have a Flarm and do not plan to purchase one,
though that could change if only there were not so many wild claims,
suggestions, scare tactics, calls for mandatory use, etc.

I only posted to this thread because of the illogic of some of the
claims and the outright falsity of others. Without going to the
calculus, I'll challenge anyone here to gain 1000' in a pullup in a
glider from 140 KIAS without performing some sort of unusual attitude
recovery afterwards.

Before retiring I worked as a systems engineer for 35 years so I know
something about specifying, designing, building, integrating, testing,
and delivering complex systems and, frankly, a lot of claims and
suggestions made here are just hogwash. You may now flame away - I'm
through trying convince some of you that the world is, indeed, round
(sorta).

On 1/6/2016 5:16 PM, Jonathan St. Cloud wrote:
> On Wednesday, January 6, 2016 at 12:03:56 PM UTC-8, Dan Marotta wrote:
>> Protocol - it's there for a reason. I understand coordinating in a
>> thermal, e.g., "BD, I'm inside your turn at 5 o'clock low", but
>> calling someone almost a mile away and suggesting that he make a
>> turn so as not to collide with me when I can simply make my own turn
>> doesn't make sense.
>>
>>
>>
>> Do you really need information on another aircraft within 300 meters
>> vertical spacing from you? That's almost 1000 feet! IFR and VFR
>> traffic routinely pass each other head on, over taking, and at
>> oblique angles with only 152 meters (500') vertical separation. I
>> can understand your concerns in and around thermals, but not in
>> cruise.
>>
> Am I mistaken or did you post that you do not have a Flarm and do not plan to purchase one?

--
Dan, 5J

Andy Blackburn[_3_]

January 8th 16, 02:20 AM

jfitch

January 8th 16, 03:24 AM

On Thursday, January 7, 2016 at 6:20:32 PM UTC-8, Andy Blackburn wrote:
> On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
> > In the spirit of technical discussion I must point out what seems to
> > me to be a basic flaw in logic.
> >
> >
> >
> > The statement that you can gain or lose altitude at 10 m/s (~20 kt)
> > is certainly valid in the US southwest.* However the supposition
> > that two gliders traveling in opposite directions with 200 meter
> > vertical separation would be at risk of collision due to one
> > suddenly dropping and the other suddenly climbing in the same
> > airmass does not appear to be a serious risk.*
>
> I think the idea is that they'd be in *different*, adjacent airmasses. Where you have strong lift you tend to have similar sink adjacent to the lift, this is true for wave, convergence and thermals. It's one reason why it's common to push over when exiting a thermal, so you can quickly traverse the sinking air surrounding the thermal (what goes up comes down somewhere nearby - that way all the air doesn't end up above the boundary layer). I've gained 1,000' pulling up in strong lift and I've seen similar opposite situations thunderstorm shelf-running. The climbing and descending gliders would not be maneuvering in the same thermal to be sure as it's hard to imagine in that case the pushing over into sink glider and the pulling up in lift glider doing anything other than diverging, but one glider pushing over to get through a veil of rain and sink while another glider is just pulling up into the strong lift under the shelf just beyond. You'd like to see that guy coming rather then letting him sneak in below the Stealth invisibility cloak and pop up into a conflict. Maybe it's just me, but I don't like surprises.
>
> Part of the challenge with selectively degrading a device like Flarm is making sure you haven't made an assumption about the scenarios that can (or can't) come up.
>
> 9B

Some people do push over in lift, and nearly everybody pulls up in lift. If you are near cloud base in a thermal and you expect sink in the ring around it (very common), a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink. This is exactly when a glider entering is pulling up. 1000 ft is nothing in this scenario.

Tango Eight

January 8th 16, 10:59 AM

On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
> a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.

No.

T8

[email protected]

January 8th 16, 01:36 PM

On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
>
>
> Some people do push over in lift, and nearly everybody pulls up in lift. If you are near cloud base in a thermal and you expect sink in the ring around it (very common), a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink. This is exactly when a glider entering is pulling up. 1000 ft is nothing in this scenario.

That is so George Moffat 70's right out of Winning on the Wind.
There is very rarely an improvement in speed made good by some very dynamic exit of a thermal. The case that would favor it is very strong lift surrounded by strong sink.
A better technique is to use the lift at the end of the climb to smoothly accelerate the glider to the desired speed before hitting the sink. Rarely would this require more than a few hundred feet at most. Modern gliders get up to speed with very little loss of altitude.
What you are describing may be fun but it is not very efficient.
Pull ups obviously can and are more dynamic but even there smoothness pays off. UH

jfitch

January 8th 16, 05:09 PM

On Friday, January 8, 2016 at 5:36:33 AM UTC-8, wrote:
<SNIP>The case that would favor it is very strong lift surrounded by strong sink.

There ya go: +10 followed by -10 not that uncommon here. The tradeoff between altitude and speed is mathematically fixed by classical physics: 1st law of thermo which I think everybody believes. It hasn't changed since the 70s (or even the 1770s). Drag of sailplanes has reduced very slightly in 45 years, which affects it very slightly. 90 knots speed reduction (from 140 -> 50) is around 700 ft. (minus energy lost due to inefficiency, but plus gain due to 10 knot thermal). Pushover form 50 -> 140 is the same, reversed.

No, I would not do that on a day with 2 knot thermals topping at 2500 ft. But I assume we want a Flarm stealth solution that works in all conditions?

Dan Marotta

January 8th 16, 05:26 PM

I'm with you, T8.

I read this exact strategy back in the 80s; I think it was in
Reichmann's book. I couldn't wait to perform a Split-S through a
thermal. I was a new guy and thought that would be cool. The "come to
Jesus" meeting at the end of the day with the other occupants of the
thermal was, shall we say, enlightening.

So here's my take on this whole Flarm "stealth" thing:

Those who want stealth mode, don't want others to be able to identify
them and become remoras. That seems a nicer word than leeches. They
state the reasons for their opposition in clear terms.

Those who don't want stealth mode want to be remoras but don't want to
admit it. In an attempt to push their view, they fall back on Mom,
apple pie, children, lawyers, and safety. We see the same arguments all
the time in other activities and they become more unlikely and extreme
with each round.

On 1/8/2016 3:59 AM, Tango Eight wrote:
> On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
>> a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.
> No.
>
> T8

--
Dan, 5J

January 8th 16, 07:56 PM

On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
> On Thursday, January 7, 2016 at 6:20:32 PM UTC-8, Andy Blackburn wrote:
> > On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
> > > In the spirit of technical discussion I must point out what seems to
> > > me to be a basic flaw in logic.
> > >
> > >
> > >
> > > The statement that you can gain or lose altitude at 10 m/s (~20 kt)
> > > is certainly valid in the US southwest.* However the supposition
> > > that two gliders traveling in opposite directions with 200 meter
> > > vertical separation would be at risk of collision due to one
> > > suddenly dropping and the other suddenly climbing in the same
> > > airmass does not appear to be a serious risk.*
> >
> > I think the idea is that they'd be in *different*, adjacent airmasses. Where you have strong lift you tend to have similar sink adjacent to the lift, this is true for wave, convergence and thermals. It's one reason why it's common to push over when exiting a thermal, so you can quickly traverse the sinking air surrounding the thermal (what goes up comes down somewhere nearby - that way all the air doesn't end up above the boundary layer). I've gained 1,000' pulling up in strong lift and I've seen similar opposite situations thunderstorm shelf-running. The climbing and descending gliders would not be maneuvering in the same thermal to be sure as it's hard to imagine in that case the pushing over into sink glider and the pulling up in lift glider doing anything other than diverging, but one glider pushing over to get through a veil of rain and sink while another glider is just pulling up into the strong lift under the shelf just beyond. You'd like to see that guy coming rather then letting him sneak in below the Stealth invisibility cloak and pop up into a conflict. Maybe it's just me, but I don't like surprises.
> >
> > Part of the challenge with selectively degrading a device like Flarm is making sure you haven't made an assumption about the scenarios that can (or can't) come up.
> >
> > 9B
>
> Some people do push over in lift, and nearly everybody pulls up in lift. If you are near cloud base in a thermal and you expect sink in the ring around it (very common), a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink. This is exactly when a glider entering is pulling up. 1000 ft is nothing in this scenario.

i know thats what moffat says to do.... but that's not a good maneuver if you are sharing the thermal.

jfitch

January 8th 16, 09:35 PM

On Friday, January 8, 2016 at 11:56:50 AM UTC-8, ND wrote:

> i know thats what moffat says to do.... but that's not a good maneuver if you are sharing the thermal.

Which is why I started with "someone who thinks they are alone in the thermal might" (if you look up thread little further).

It is perhaps another east/west divide thing that need to be considered in any solution. The thermals in the west can be very strong, as the sink can also be, and speeds are quite high by comparison. I'm not sure the same parameters are going to apply to both, as others have also suggested. That means, without further epiphanies, two stealth modes.

Andy Blackburn[_3_]

January 8th 16, 10:18 PM

On Friday, January 8, 2016 at 5:36:33 AM UTC-8, wrote:
Rarely would this require more than a few hundred feet at most. Modern gliders get up to speed with very little loss of altitude.
> What you are describing may be fun but it is not very efficient.
> Pull ups obviously can and are more dynamic but even there smoothness pays off. UH

A little math would help - but this seems roughly right.

Any decending air outside a thermal would likely be more gentle than the rising air at the core. I have certainly found I could gain more than 1,000 feet within 15 or 20 seconds with a smooth pull-up into a strong thermal.

We are talking about having adequate closing time (of around 45 seconds) from first being put on the traffic screen until potential collision - and not being . A glider running in say 3 knots of sink at 110 kts will lose around 500 feet in 45 seconds and a glider pulling up into lift might gain 7-800 from the pull-up and another 3-500 from the lift over that time period for a total of 1500-1800 feet net change (assuming the run into the thermal didn't also have some lift). Anything less creates a scenario where you can sneak in outside of the altitude filter for stealth and come into view with less than the requisite 45 seconds. Less than 1200 or so and the surprise can be quite sudden - maybe 8-10 seconds.

Of course getting into lines of lift can yield many different scenarios - running storm shelves is a common tactic, but so is convergence and occasionally wave - all have pairings of strong lift and some level of sink and pairings of gliders maneuvering. The fact that sink tends to generate push-overs and lift tends to generate pull-ups means that the effects are amplified, rather than canceling, so you need to look at both together.

9B

January 9th 16, 04:19 AM

On Friday, January 8, 2016 at 8:03:36 PM UTC-8, Dan Marotta wrote:
> I'm with you, T8.
>
>
>
> I read this exact strategy back in the 80s; I think it was in
> Reichmann's book.* I couldn't wait to perform a Split-S through a
> thermal.* I was a new guy and thought that would be cool.* The "come
> to Jesus" meeting at the end of the day with the other occupants of
> the thermal was, shall we say, enlightening.
>
>
>
> So here's my take on this whole Flarm "stealth" thing:
>
>
>
> Those who want stealth mode, don't want others to be able to
> identify them and become remoras.* That seems a nicer word than
> leeches.* They state the reasons for their opposition in clear
> terms.
>
>
>
> Those who don't want stealth mode want to be remoras but don't want
> to admit it.* In an attempt to push their view, they fall back on
> Mom, apple pie, children, lawyers, and safety.* We see the same
> arguments all the time in other activities and they become more
> unlikely and extreme with each round.
>
>
>
>
> On 1/8/2016 3:59 AM, Tango Eight wrote:
>
>
>
> On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
>
>
> a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.
>
>
> No.
>
> T8
>
>
>
>
>
> --
>
> Dan, 5J

Hahaaaaa!
New subject.
Jim

kirk.stant

January 9th 16, 03:09 PM

On Friday, January 8, 2016 at 10:03:36 PM UTC-6, Dan Marotta wrote:

> So here's my take on this whole Flarm "stealth" thing:

> Those who want stealth mode, don't want others to be able to
> identify them and become remoras.* That seems a nicer word than
> leeches.* They state the reasons for their opposition in clear
> terms.

> Those who don't want stealth mode want to be remoras but don't want
> to admit it.* In an attempt to push their view, they fall back on
> Mom, apple pie, children, lawyers, and safety.* We see the same
> arguments all the time in other activities and they become more
> unlikely and extreme with each round.

Dan, considering you don't fly with a PowerFlarm and don't currently race, your comments are somewhat simplistic.

I've had PF since the day it came out, and have raced with it (in your stomping grounds, by the way). I love the situational awareness it provides, and think it makes racing a lot more fun, as well as safer. If you carefully read all the threads on this subject, you find a few hard core "IT WILL RUIN RACING AS WE KNOW IT!!!" proponents of stealth, a few hard core "MANDATE STEALTH AND ILL NEVER RACE AGAIN", and a lot of "I really like full flarm SA and I worry about mid-airs, is there a way we can compromise? My personal take is that the leeching argument is way overblown with the attendance at US contests, otherwise everybody would be carrying binoculars and all the young guys with 20-10 eyes would be winning. And having picked up USAFA Duo's(all USAFA racing gliders have PF) head on co-altitude under a cloud street over 10 km on the nose, I REALLY dont want to give up that capability.

All this knashing of teeth about how to tweek "stealth" to "competition" that will please everybody seems pointless to me. As others have pointed out, ADS-B out is coming, and if a cheap 1090ES system for UAVs comes out soon, I bet you will see it explode in gliders, and with PF you will see all those guys regardless of stealth or competition modes.

Instead of whining, we should all embrace the new technology and the capability it brings, and find new ways to use it. Despite what many nay-sayers are claiming, for the average racing pilot full up flarm makes a contest more enjoyable and safer - and isn't that really the point of it?

You should borrow a portable PF and try it - you may find that opens your eyes on what is really flying around in your airspace - you'll be able to see those airliners deviate around you!

Cheers from cold, wet, dreary St Louis.

Kirk
66

Andrzej Kobus

January 9th 16, 03:21 PM

On Friday, January 8, 2016 at 11:03:36 PM UTC-5, Dan Marotta wrote:
> I'm with you, T8.
>
>
>
> I read this exact strategy back in the 80s; I think it was in
> Reichmann's book.* I couldn't wait to perform a Split-S through a
> thermal.* I was a new guy and thought that would be cool.* The "come
> to Jesus" meeting at the end of the day with the other occupants of
> the thermal was, shall we say, enlightening.
>
>
>
> So here's my take on this whole Flarm "stealth" thing:
>
>
>
> Those who want stealth mode, don't want others to be able to
> identify them and become remoras.* That seems a nicer word than
> leeches.* They state the reasons for their opposition in clear
> terms.
>
>
>
> Those who don't want stealth mode want to be remoras but don't want
> to admit it.* In an attempt to push their view, they fall back on
> Mom, apple pie, children, lawyers, and safety.* We see the same
> arguments all the time in other activities and they become more
> unlikely and extreme with each round.
>
>
>
>
> On 1/8/2016 3:59 AM, Tango Eight wrote:
>
>
>
> On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
>
>
> a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.
>
>
> No.
>
> T8
>
>
>
>
>
> --
>
> Dan, 5J

Dan, I specifically asked to keep this thread clean from any comments not related to finding a solution. Please take your comments to another thread and argue there. These comments bring no value towards finding a solution. This thread was intended to bring people together to find a solution not to create another divide.

To all, let's not get engaged in questioning each other motives.

Regards,
Andrzej

Steve Koerner

January 9th 16, 03:33 PM

Well said Kirk.

The premise of this thread, that there should be some acceptable way to degrade the behavior of a safety device is just off base. We should only be looking to Flarm folks for ways to improve safety performance. That is their mission - no nonsense, no confusion about goals please.

Dan Marotta

January 9th 16, 05:14 PM

Hi Kirk,

Yes, I've towed you during at least one contest at Moriarty and I've
admired your LS-6.

Please understand that I don't "poo-poo" Flarm in my comments, I only
respond to the comments of some, which I believe are unreasonable or
downright wrong. I always welcome logical proofs like the math-based
analysis of the pull-up (in a previous thread).

And yes, I think Flarm is a great tool for situational awareness but I
don't think that knowing a blip's ID is a requirement for safety. And
I'm neither for nor against "stealth" mode - I don't care either way.
The idea of coordinating an escape plan with another aircraft 5 miles
away by radio is simply ludicrous. Remember when contests were fully
manned and there was no Flarm or GPS? I'm not against either, as a lot
of the folks here think, but I think a lot of the fun has gone and
that's the main reason I don't fly contests any more.

So why do I keep posting? It's out of a genuine concern that false
perceptions, unchallenged, will eventually become policy, and I don't
want any more policies.

On 1/9/2016 8:09 AM, kirk.stant wrote:
> On Friday, January 8, 2016 at 10:03:36 PM UTC-6, Dan Marotta wrote:
>
>> So here's my take on this whole Flarm "stealth" thing:
>> Those who want stealth mode, don't want others to be able to
>> identify them and become remoras. That seems a nicer word than
>> leeches. They state the reasons for their opposition in clear
>> terms.
>> Those who don't want stealth mode want to be remoras but don't want
>> to admit it. In an attempt to push their view, they fall back on
>> Mom, apple pie, children, lawyers, and safety. We see the same
>> arguments all the time in other activities and they become more
>> unlikely and extreme with each round.
> Dan, considering you don't fly with a PowerFlarm and don't currently race, your comments are somewhat simplistic.
>
> I've had PF since the day it came out, and have raced with it (in your stomping grounds, by the way). I love the situational awareness it provides, and think it makes racing a lot more fun, as well as safer. If you carefully read all the threads on this subject, you find a few hard core "IT WILL RUIN RACING AS WE KNOW IT!!!" proponents of stealth, a few hard core "MANDATE STEALTH AND ILL NEVER RACE AGAIN", and a lot of "I really like full flarm SA and I worry about mid-airs, is there a way we can compromise? My personal take is that the leeching argument is way overblown with the attendance at US contests, otherwise everybody would be carrying binoculars and all the young guys with 20-10 eyes would be winning. And having picked up USAFA Duo's(all USAFA racing gliders have PF) head on co-altitude under a cloud street over 10 km on the nose, I REALLY dont want to give up that capability.
>
> All this knashing of teeth about how to tweek "stealth" to "competition" that will please everybody seems pointless to me. As others have pointed out, ADS-B out is coming, and if a cheap 1090ES system for UAVs comes out soon, I bet you will see it explode in gliders, and with PF you will see all those guys regardless of stealth or competition modes.
>
> Instead of whining, we should all embrace the new technology and the capability it brings, and find new ways to use it. Despite what many nay-sayers are claiming, for the average racing pilot full up flarm makes a contest more enjoyable and safer - and isn't that really the point of it?
>
> You should borrow a portable PF and try it - you may find that opens your eyes on what is really flying around in your airspace - you'll be able to see those airliners deviate around you!
>
> Cheers from cold, wet, dreary St Louis.
>
> Kirk
> 66

--
Dan, 5J

January 9th 16, 08:08 PM

On Saturday, January 9, 2016 at 12:14:07 PM UTC-5, Dan Marotta wrote:
> Hi Kirk,
>
>
>
> Yes, I've towed you during at least one contest at Moriarty and I've
> admired your LS-6.
>
>
>
> Please understand that I don't "poo-poo" Flarm in my comments, I
> only respond to the comments of some, which I believe are
> unreasonable or downright wrong.* I always welcome logical proofs
> like the math-based analysis of the pull-up (in a previous thread).
>
>
>
> And yes, I think Flarm is a great tool for situational awareness but
> I don't think that knowing a blip's ID is a requirement for safety.*
> And I'm neither for nor against "stealth" mode - I don't care either
> way.* The idea of coordinating an escape plan with another aircraft
> 5 miles away by radio is simply ludicrous.* Remember when contests
> were fully manned and there was no Flarm or GPS?* I'm not against
> either, as a lot of the folks here think, but I think a lot of the
> fun has gone and that's the main reason I don't fly contests any
> more.
>
>
>
> So why do I keep posting?* It's out of a genuine concern that false
> perceptions, unchallenged, will eventually become policy, and I
> don't want any more policies.

Thank you Dan for your posts. Your opinion is important, too. I especially agree with this last paragraph.

I'll give you one example that needs to be challenged stated just a little while back. One post says"the requisite 45 seconds" and goes into some simple calculations based on 45 seconds on the display. I would like to see some actual physics calculated, but aside from that there is no basis for the 45 seconds. This is the kind of overstatement I keep talking about. It is not a lie but people are trying so hard to make their case for the outcome they desire they sometimes overstate the facts.

Pull out your iPhone and run the timer for 45seconds and you'll see it is a lot of time. There are other alternatives that may help. When a new target appears on the screen there can be simple audio alert letting you know of the new bogie. I would suggest that in this case 25 seconds of warning is plenty if collision avoidance is what you are really after. Don't take my word for it though, use some real science to come up with a real number.

The TCAS operators guide that I am looking at allows 5 secs as the outside reaction time to initiate corrective action (pitch change in the case of TCAS) resolution advisory. This is similar to the FLARM warning when a collision path is detected. I don't have complete TCAS specs readily available but perhaps other time values from TCAS could be used since their research is probably more thorough.

It makes a big difference in the final numbers if you use 45 seconds or 25 seconds. Let's make sure these numbers are based on some evidence.

XC

kirk.stant

January 9th 16, 09:56 PM

On Saturday, January 9, 2016 at 11:14:07 AM UTC-6, Dan Marotta wrote:
> Hi Kirk,
>
>
>
> Yes, I've towed you during at least one contest at Moriarty and I've
> admired your LS-6.
>
>
>
> Please understand that I don't "poo-poo" Flarm in my comments, I
> only respond to the comments of some, which I believe are
> unreasonable or downright wrong.* I always welcome logical proofs
> like the math-based analysis of the pull-up (in a previous thread).
>
>
>
> And yes, I think Flarm is a great tool for situational awareness but
> I don't think that knowing a blip's ID is a requirement for safety.*
> And I'm neither for nor against "stealth" mode - I don't care either
> way.* The idea of coordinating an escape plan with another aircraft
> 5 miles away by radio is simply ludicrous.* Remember when contests
> were fully manned and there was no Flarm or GPS?* I'm not against
> either, as a lot of the folks here think, but I think a lot of the
> fun has gone and that's the main reason I don't fly contests any
> more.
>
>
>
> So why do I keep posting?* It's out of a genuine concern that false
> perceptions, unchallenged, will eventually become policy, and I
> don't want any more policies.

Dan, by all means keep on posting - we need some grown-up input here now and then! But seriously, I haven't been convinced by any of the pro-stealth arguments. I would argue we should go the other way - full tracking of ALL contestants, shown in the cockpit, and let everyone share the info from all.. This may come from my sailing experience (racing Lasers), where you are immersed in the fleet, know who the hot shots are, and can see who is benefiting from wind changes, lulls, etc - all of which makes the race a much more involving event, and from my dislike of "OLC racing", which I find pretty boring (aside from not being racing in the real sense, IMO).

But then, I like the company of other gliders when I race - I must be channeling some residual Red Flag memories ;^).

Cheers,

Kirk
66

jfitch

January 10th 16, 12:30 AM

On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
<SNIP>>Let's make sure these numbers are based on some evidence.

Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.

The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.

Dave Leonard

January 10th 16, 01:33 AM

On Saturday, January 9, 2016 at 5:30:48 PM UTC-7, jfitch wrote:
> On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> <SNIP>>Let's make sure these numbers are based on some evidence.
>
> Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
>
> The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.

TCAS is a completely different kind of system designed to work in an IFR environment. It is not GPS based. It is on board radar / transponder based. It gives specific commands to the flight crew to avoid the possible collision. Simple pull up or push over commands. The crew is expected to just do what the machine says, then tell ATC they got an RA and that's why they deviated. Visually spotting the traffic is irrelevant. Reaction time is just how quickly the crew can execute the command. No decision about what to do, just safely interrupt current process and execute.

FLARM makes absolutely no attempt to recommend how to avoid a collision. It just points out traffic and highlights potentially conflicting traffic based on the assumption both aircraft will continue to do what they have been doing. Its up to the pilot(s) to decide what to do, preferably after visually spotting the threat.

January 10th 16, 01:47 AM

On Saturday, January 9, 2016 at 7:30:48 PM UTC-5, jfitch wrote:
> On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> <SNIP>>Let's make sure these numbers are based on some evidence.
>
> Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
>
> The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.

More details about TCAS for comparison:

5 sec. is the maximum expected reaction time for a warning or RA. That is with the autopilot engaged and the pilot not actively engaged on the flight controls. The anticipated reaction time to reverse, increase or decrease vertical speed once the pilot is flying the machine is 2.5 sec.

"Initial vertical speed reaction to a RA is expected within 5 seconds; maneuvering G forces should be similar to those felt when responding to an ATC clearance to climb or defend "immediately" (+/- 0.25 G change in load factor)." That doesn't sound too panicked.

The TCAS display is selectable Above/Norm/Below. My company recommends normal in all phases of flight which gives +/- 2700 ft on the display. This is for aircraft capable of climbing or descending 6000 ft/min. "Above" can be selected in the climb which would give a view of aircraft 7000 ft above and 2700 ft below.

Now this is a different system, I understand, but my point is that it is not cross referenced continuously as a source of SA. Rather, it is an alert system that provides traffic advisories (TA) as aircraft are getting to be a factor ("Traffic") and resolution advisories (RA) ("Traffic, Climb/Descend)"when action is required by the pilot. The audio alerts and warnings have priority and have been determined to be more effective than the instrument panel display for collision avoidance.

Similarly, displaying all traffic on FLARM at these greater distances and relative altitudes is not required for SA or collision avoidance. In fact, spending too much time looking down at the display may be contrary to safety.. Again, this discussion goes beyond collision avoidance and gets into pilots wanting to track other gliders for tactical reasons.

XC

smfidler

January 10th 16, 05:57 AM

XC,

Again, you assume the flawless function of the Flarm system. 25 seconds, if the Flarm "network" is not perfectly functional due to say structural interference, may be reduced to 5 seconds. Or zero. Arbitrary discussions about were "safety ends" and "philosophical Flarm fairness?" (whatever the hell this should be) begins has proven quite frightening to observe.

The longer the time period the Flarm has to make a potential warning (beep as "bogey" appears), the better. This is a fact (from a safety viewpoint). Artificial reductions in Flarms engineered performance potential will by definition also increase the odds of a dangerous situation occurring. While being far better than nothing, the Flarm network is still prone to regular coverage challenges and clearly does not have, perfect, 100%, 360 degree coverage at all times. Far, FAR from it.

We need to kill this whole idea for at least one year. It's out of control.. It is irresponsible (at best) to screw around with Flarms potential range at this point. The unintended consequences are potentially huge. The philosophical competitive "fairness" argument is simply no peer to safety. It's not even on the same planet as safety. Stop treating this discussion like this as a debate between equals. Start respecting the fact that Flarm, while valuable for safety, is far, far from perfect or infallible. So when you say a supposed time value that you find acceptable for your little crusade, imagine that the gliders 25 seconds away from a potential collision are not seeing each others antenna at 25 seconds for whatever reason. Or maybe you get a proximity "beep" and then lose coverage for 15 seconds.

Bottom line, some here care far more about philosophical fairness arguments than the significant safety value Flarm provides via its ability to create situational awareness for us. This crusade become an literal obsession for some.

I won't debate or compromise Flarm at this point until some sort of impartial, objective study (and extensive testing) has been completed. This was the requirement of my initial support for a limitation. Since then, the almost reckless abandon that many supporters (almost certainly coordinated in a pseudo RAS Flarm "mode" campaign) have demonstrated here is a real problem. The USRC opinion poll does not support this desperate position.

Perhaps the FAA should be involved. Has anyone discussed this topic with the FAA? I wonder what their take would be.

Sean

jfitch

January 10th 16, 07:07 AM

On Saturday, January 9, 2016 at 5:47:04 PM UTC-8, XC wrote:
> On Saturday, January 9, 2016 at 7:30:48 PM UTC-5, jfitch wrote:
> > On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> > <SNIP>>Let's make sure these numbers are based on some evidence.
> >
> > Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
> >
> > The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.
>
> More details about TCAS for comparison:
>
> 5 sec. is the maximum expected reaction time for a warning or RA. That is with the autopilot engaged and the pilot not actively engaged on the flight controls. The anticipated reaction time to reverse, increase or decrease vertical speed once the pilot is flying the machine is 2.5 sec.
>
> "Initial vertical speed reaction to a RA is expected within 5 seconds; maneuvering G forces should be similar to those felt when responding to an ATC clearance to climb or defend "immediately" (+/- 0.25 G change in load factor)." That doesn't sound too panicked.
>
> The TCAS display is selectable Above/Norm/Below. My company recommends normal in all phases of flight which gives +/- 2700 ft on the display. This is for aircraft capable of climbing or descending 6000 ft/min. "Above" can be selected in the climb which would give a view of aircraft 7000 ft above and 2700 ft below.
>
> Now this is a different system, I understand, but my point is that it is not cross referenced continuously as a source of SA. Rather, it is an alert system that provides traffic advisories (TA) as aircraft are getting to be a factor ("Traffic") and resolution advisories (RA) ("Traffic, Climb/Descend)"when action is required by the pilot. The audio alerts and warnings have priority and have been determined to be more effective than the instrument panel display for collision avoidance.
>
> Similarly, displaying all traffic on FLARM at these greater distances and relative altitudes is not required for SA or collision avoidance. In fact, spending too much time looking down at the display may be contrary to safety. Again, this discussion goes beyond collision avoidance and gets into pilots wanting to track other gliders for tactical reasons.
>
> XC

In searching for the best anti collision system, few people hold out TCAS as the ideal. I have heard much more criticism of it than praise, the latter usually confined to "it's better than nothing". This is why the regulators and industry worldwide are moving as fast as they possibly can towards ADS-B, a system much more like Flarm. Before we decide that the metrics of TCAS are ideal or even adequate, we should ask why that system is being discarded in favor of one that shows all aircraft within 15 miles, all the time: position, altitude, and tail number. Going by that metric, the FAA has already decided that 15 miles range is the right answer. Even at 1000 mph closing speed, 15 miles gives over 50 seconds warning. I propose 50 seconds is the best supported number.

Darryl Ramm

January 10th 16, 07:54 AM

On Saturday, January 9, 2016 at 11:07:04 PM UTC-8, jfitch wrote:
> On Saturday, January 9, 2016 at 5:47:04 PM UTC-8, XC wrote:
> > On Saturday, January 9, 2016 at 7:30:48 PM UTC-5, jfitch wrote:
> > > On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> > > <SNIP>>Let's make sure these numbers are based on some evidence.
> > >
> > > Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
> > >
> > > The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.
> >
> > More details about TCAS for comparison:
> >
> > 5 sec. is the maximum expected reaction time for a warning or RA. That is with the autopilot engaged and the pilot not actively engaged on the flight controls. The anticipated reaction time to reverse, increase or decrease vertical speed once the pilot is flying the machine is 2.5 sec.
> >
> > "Initial vertical speed reaction to a RA is expected within 5 seconds; maneuvering G forces should be similar to those felt when responding to an ATC clearance to climb or defend "immediately" (+/- 0.25 G change in load factor)." That doesn't sound too panicked.
> >
> > The TCAS display is selectable Above/Norm/Below. My company recommends normal in all phases of flight which gives +/- 2700 ft on the display. This is for aircraft capable of climbing or descending 6000 ft/min. "Above" can be selected in the climb which would give a view of aircraft 7000 ft above and 2700 ft below.
> >
> > Now this is a different system, I understand, but my point is that it is not cross referenced continuously as a source of SA. Rather, it is an alert system that provides traffic advisories (TA) as aircraft are getting to be a factor ("Traffic") and resolution advisories (RA) ("Traffic, Climb/Descend)"when action is required by the pilot. The audio alerts and warnings have priority and have been determined to be more effective than the instrument panel display for collision avoidance.
> >
> > Similarly, displaying all traffic on FLARM at these greater distances and relative altitudes is not required for SA or collision avoidance. In fact, spending too much time looking down at the display may be contrary to safety. Again, this discussion goes beyond collision avoidance and gets into pilots wanting to track other gliders for tactical reasons.
> >
> > XC
>
> In searching for the best anti collision system, few people hold out TCAS as the ideal. I have heard much more criticism of it than praise, the latter usually confined to "it's better than nothing". This is why the regulators and industry worldwide are moving as fast as they possibly can towards ADS-B, a system much more like Flarm. Before we decide that the metrics of TCAS are ideal or even adequate, we should ask why that system is being discarded in favor of one that shows all aircraft within 15 miles, all the time: position, altitude, and tail number. Going by that metric, the FAA has already decided that 15 miles range is the right answer. Even at 1000 mph closing speed, 15 miles gives over 50 seconds warning. I propose 50 seconds is the best supported number.

Oh what a pile of utter nonsense. TCAS II *is* the gold standard in collision avoidance. ADS-B does not replace TCAS II in *any* way. Not a single FAA regulation currently or proposed allows for replacement of TCAS II mandatory carriage with any ADS-B product.

TCAS II is not being discarded/abandoned for anything, including ADS-B anything. There is no technology that uses ADS-B for active collision avoidance similar to TCAS available as any RTCA standard and so nothing that can be build and no research projects that could be turned into such a standards any time soon. So at best anything based on ADS-B would likely be decades away. I have now idea where you are getting this 15 miles from. The ADS-B ground services hockey-puck diameter? That really has no direct relevance to TCAS. It is a stopgap layered on a complex dual-link mess.

TCAS II version 7.1 (the current standard) makes use of ADS-B In data to reduce the activeTCAS II transponder interrogation rates and provide better long range tracking of targets (esp. without excessive RF congestion). These systems do not use ADS-B data to issue an RA, that is all determined by active TCAS II to transponder interrogation. One of the specific advantages of Change 7.1 ADS-B integration is improved long range (much longer than 15nm you mention) traffic display... which in USA Class A airspace they will be able to rely on every aircraft being quipped with after 2020.

So not a single thing you stated is correct.

January 10th 16, 10:42 AM

On Sunday, January 10, 2016 at 12:57:03 AM UTC-5, smfidler wrote:
> XC,
>
> Again, you assume the flawless function of the Flarm system. 25 seconds, if the Flarm "network" is not perfectly functional due to say structural interference, may be reduced to 5 seconds. Or zero. Arbitrary discussions about were "safety ends" and "philosophical Flarm fairness?" (whatever the hell this should be) begins has proven quite frightening to observe.
>
> The longer the time period the Flarm has to make a potential warning (beep as "bogey" appears), the better. This is a fact (from a safety viewpoint). Artificial reductions in Flarms engineered performance potential will by definition also increase the odds of a dangerous situation occurring. While being far better than nothing, the Flarm network is still prone to regular coverage challenges and clearly does not have, perfect, 100%, 360 degree coverage at all times. Far, FAR from it.
>
> We need to kill this whole idea for at least one year. It's out of control. It is irresponsible (at best) to screw around with Flarms potential range at this point. The unintended consequences are potentially huge. The philosophical competitive "fairness" argument is simply no peer to safety. It's not even on the same planet as safety. Stop treating this discussion like this as a debate between equals. Start respecting the fact that Flarm, while valuable for safety, is far, far from perfect or infallible. So when you say a supposed time value that you find acceptable for your little crusade, imagine that the gliders 25 seconds away from a potential collision are not seeing each others antenna at 25 seconds for whatever reason. Or maybe you get a proximity "beep" and then lose coverage for 15 seconds.
>
> Bottom line, some here care far more about philosophical fairness arguments than the significant safety value Flarm provides via its ability to create situational awareness for us. This crusade become an literal obsession for some.
>
> I won't debate or compromise Flarm at this point until some sort of impartial, objective study (and extensive testing) has been completed. This was the requirement of my initial support for a limitation. Since then, the almost reckless abandon that many supporters (almost certainly coordinated in a pseudo RAS Flarm "mode" campaign) have demonstrated here is a real problem. The USRC opinion poll does not support this desperate position.
>
> Perhaps the FAA should be involved. Has anyone discussed this topic with the FAA? I wonder what their take would be.
>

I was just pointing out some of the time values involved in operating with TCAS. I suspect that research was more extensive and the technology is more proven. Many TCAS resolution advisories occur before they are displayed as targets on the screen. The pilot's eyes are directed to the display (on the VSI in our case) to make a correction because it is a system used during IFR.

With FLARM the eyes are directed outside as they should be. The best way to do this is through the audio warning system. More could be done with this to improve safety. For example, there could be a warning "Multiple traffic, One o'clock high." This is another real suggestion that would enhance the FLARM system. The TCAS time values are real numbers to add perspective to the discussion.

XC

Greg Delp

January 10th 16, 02:45 PM

On Sunday, January 10, 2016 at 5:42:30 AM UTC-5, XC wrote:
> On Sunday, January 10, 2016 at 12:57:03 AM UTC-5, smfidler wrote:
> > XC,
> >
> > Again, you assume the flawless function of the Flarm system. 25 seconds, if the Flarm "network" is not perfectly functional due to say structural interference, may be reduced to 5 seconds. Or zero. Arbitrary discussions about were "safety ends" and "philosophical Flarm fairness?" (whatever the hell this should be) begins has proven quite frightening to observe.
> >
> > The longer the time period the Flarm has to make a potential warning (beep as "bogey" appears), the better. This is a fact (from a safety viewpoint). Artificial reductions in Flarms engineered performance potential will by definition also increase the odds of a dangerous situation occurring. While being far better than nothing, the Flarm network is still prone to regular coverage challenges and clearly does not have, perfect, 100%, 360 degree coverage at all times. Far, FAR from it.
> >
> > We need to kill this whole idea for at least one year. It's out of control. It is irresponsible (at best) to screw around with Flarms potential range at this point. The unintended consequences are potentially huge. The philosophical competitive "fairness" argument is simply no peer to safety.. It's not even on the same planet as safety. Stop treating this discussion like this as a debate between equals. Start respecting the fact that Flarm, while valuable for safety, is far, far from perfect or infallible. So when you say a supposed time value that you find acceptable for your little crusade, imagine that the gliders 25 seconds away from a potential collision are not seeing each others antenna at 25 seconds for whatever reason. Or maybe you get a proximity "beep" and then lose coverage for 15 seconds.
> >
> > Bottom line, some here care far more about philosophical fairness arguments than the significant safety value Flarm provides via its ability to create situational awareness for us. This crusade become an literal obsession for some.
> >
> > I won't debate or compromise Flarm at this point until some sort of impartial, objective study (and extensive testing) has been completed. This was the requirement of my initial support for a limitation. Since then, the almost reckless abandon that many supporters (almost certainly coordinated in a pseudo RAS Flarm "mode" campaign) have demonstrated here is a real problem. The USRC opinion poll does not support this desperate position.
> >
> > Perhaps the FAA should be involved. Has anyone discussed this topic with the FAA? I wonder what their take would be.
> >
>
> I was just pointing out some of the time values involved in operating with TCAS. I suspect that research was more extensive and the technology is more proven. Many TCAS resolution advisories occur before they are displayed as targets on the screen. The pilot's eyes are directed to the display (on the VSI in our case) to make a correction because it is a system used during IFR.
>
> With FLARM the eyes are directed outside as they should be. The best way to do this is through the audio warning system. More could be done with this to improve safety. For example, there could be a warning "Multiple traffic, One o'clock high." This is another real suggestion that would enhance the FLARM system. The TCAS time values are real numbers to add perspective to the discussion.
>
> XC

Then point out all the time values not just the ones that seem to support your stance on stealth. TCAS Non threat traffic more than 6 miles away can be displayed to well over 40 miles away. Proximity intruder traffic less than 6 miles away fill in the diamond display(visual no audio) to get your attention and provide situation awareness to prevent surprise TA and RA alerts. Traffic Alerts (TA) for potential collisions will happen from 20-48 seconds to closest point of approach(collision) with a visual change to yellow diamond and audio "Traffic Traffic" Under normal conditions a TA will proceed an RA by 15 seconds which prepares the pilots for any required RA avoidance maneuver while giving time to acquire the target visually if possible.. Resolution Advisories (RA) which TCAS deems an imminent collision threat with a time of closest approach of 15-35 seconds warns with a red diamond visual cue and audio avoidance commands (Climb Climb Climb, Monitor Vertical speed etc...) as well as the required vertical speed required for the 5 second maneuver you posted.

TCAS uses these multiple steps of awareness from well over 40 miles away to try and prevent surprise RAs as well as to give crews the time required to scan visually for the traffic. I also find it very hard to believe there have been many instant RAs without the targets going through the normal threat scales of non threat, proximity, TA, RA, Clear of Conflict or at least some of them. Does it happen yes but it is not the norm.

To suggest that your eyes are inside looking at the TCAS only because you are IFR is misleading. It gives you the fastest way of locating the direction and altitude of the potential collision traffic so you can then start looking visually for the traffic if your not in clouds. No one using TCAS gets a pop up TA and starts randomly visually scanning the sky hoping to see the traffic. It takes much longer than looking at the TCAS visual display for a split second to find out where the traffic is then back outside to find it visually.

This is exactly the same method that FLARM uses with a scaled response to traffic threats as they get closer and are deemed a threat. Both TCAS and FLARM allow much better situational awareness of traffic. I would argue that FLARM stealth mode is exactly like the pop up surprise TCAS RA example you used. It should never happen as there is only 5 seconds to respond. TCAS users get the advantage of a computer giving an immediately calculated escape maneuver. FLARM users only have seconds to find the traffic visually to find out what to do.

Andy Blackburn[_3_]

January 10th 16, 04:50 PM

On Sunday, January 10, 2016 at 6:45:59 AM UTC-8, Greg Delp wrote:
> On Sunday, January 10, 2016 at 5:42:30 AM UTC-5, XC wrote:
> > On Sunday, January 10, 2016 at 12:57:03 AM UTC-5, smfidler wrote:
> > > XC,
> > >
> > > Again, you assume the flawless function of the Flarm system. 25 seconds, if the Flarm "network" is not perfectly functional due to say structural interference, may be reduced to 5 seconds. Or zero. Arbitrary discussions about were "safety ends" and "philosophical Flarm fairness?" (whatever the hell this should be) begins has proven quite frightening to observe.
> > >
> > > The longer the time period the Flarm has to make a potential warning (beep as "bogey" appears), the better. This is a fact (from a safety viewpoint). Artificial reductions in Flarms engineered performance potential will by definition also increase the odds of a dangerous situation occurring. While being far better than nothing, the Flarm network is still prone to regular coverage challenges and clearly does not have, perfect, 100%, 360 degree coverage at all times. Far, FAR from it.
> > >
> > > We need to kill this whole idea for at least one year. It's out of control. It is irresponsible (at best) to screw around with Flarms potential range at this point. The unintended consequences are potentially huge. The philosophical competitive "fairness" argument is simply no peer to safety. It's not even on the same planet as safety. Stop treating this discussion like this as a debate between equals. Start respecting the fact that Flarm, while valuable for safety, is far, far from perfect or infallible. So when you say a supposed time value that you find acceptable for your little crusade, imagine that the gliders 25 seconds away from a potential collision are not seeing each others antenna at 25 seconds for whatever reason. Or maybe you get a proximity "beep" and then lose coverage for 15 seconds..
> > >
> > > Bottom line, some here care far more about philosophical fairness arguments than the significant safety value Flarm provides via its ability to create situational awareness for us. This crusade become an literal obsession for some.
> > >
> > > I won't debate or compromise Flarm at this point until some sort of impartial, objective study (and extensive testing) has been completed. This was the requirement of my initial support for a limitation. Since then, the almost reckless abandon that many supporters (almost certainly coordinated in a pseudo RAS Flarm "mode" campaign) have demonstrated here is a real problem. The USRC opinion poll does not support this desperate position.
> > >
> > > Perhaps the FAA should be involved. Has anyone discussed this topic with the FAA? I wonder what their take would be.
> > >
> >
> > I was just pointing out some of the time values involved in operating with TCAS. I suspect that research was more extensive and the technology is more proven. Many TCAS resolution advisories occur before they are displayed as targets on the screen. The pilot's eyes are directed to the display (on the VSI in our case) to make a correction because it is a system used during IFR.
> >
> > With FLARM the eyes are directed outside as they should be. The best way to do this is through the audio warning system. More could be done with this to improve safety. For example, there could be a warning "Multiple traffic, One o'clock high." This is another real suggestion that would enhance the FLARM system. The TCAS time values are real numbers to add perspective to the discussion.
> >
> > XC
>
> Then point out all the time values not just the ones that seem to support your stance on stealth. TCAS Non threat traffic more than 6 miles away can be displayed to well over 40 miles away. Proximity intruder traffic less than 6 miles away fill in the diamond display(visual no audio) to get your attention and provide situation awareness to prevent surprise TA and RA alerts. Traffic Alerts (TA) for potential collisions will happen from 20-48 seconds to closest point of approach(collision) with a visual change to yellow diamond and audio "Traffic Traffic" Under normal conditions a TA will proceed an RA by 15 seconds which prepares the pilots for any required RA avoidance maneuver while giving time to acquire the target visually if possible. Resolution Advisories (RA) which TCAS deems an imminent collision threat with a time of closest approach of 15-35 seconds warns with a red diamond visual cue and audio avoidance commands (Climb Climb Climb, Monitor Vertical speed etc...) as well as the required vertical speed required for the 5 second maneuver you posted.
>
>
> TCAS uses these multiple steps of awareness from well over 40 miles away to try and prevent surprise RAs as well as to give crews the time required to scan visually for the traffic. I also find it very hard to believe there have been many instant RAs without the targets going through the normal threat scales of non threat, proximity, TA, RA, Clear of Conflict or at least some of them. Does it happen yes but it is not the norm.
>
> To suggest that your eyes are inside looking at the TCAS only because you are IFR is misleading. It gives you the fastest way of locating the direction and altitude of the potential collision traffic so you can then start looking visually for the traffic if your not in clouds. No one using TCAS gets a pop up TA and starts randomly visually scanning the sky hoping to see the traffic. It takes much longer than looking at the TCAS visual display for a split second to find out where the traffic is then back outside to find it visually.
>
> This is exactly the same method that FLARM uses with a scaled response to traffic threats as they get closer and are deemed a threat. Both TCAS and FLARM allow much better situational awareness of traffic. I would argue that FLARM stealth mode is exactly like the pop up surprise TCAS RA example you used. It should never happen as there is only 5 seconds to respond. TCAS users get the advantage of a computer giving an immediately calculated escape maneuver. FLARM users only have seconds to find the traffic visually to find out what to do.

There has been lots of good work on human reaction times (much of it as relates to OODA-loop types of cognitive processing). If you also look at the research studies done on visual scan and collision avoidance, you realize that there are some profound differences between how Flarm and TCAS operate with the pilot(s) in the loop. An RA climb/decend command is pretty unambiguous and the context is pretty clear - push or pull on the stick as commanded or you will hit someone. You can act with confidence that the systems is giving complementary commands if both aircraft are TCAS II equipped. The "Orient" phase of this "Observe-Orient-Decide-Act" loop in collision avoidance has the biggest potential variance in time because it is not always 100% clear what is happening based on limited inputs. An RA cuts this time down dramatically, just Act on what the system tells you. Flarm doesn't do this so the pilot needs to go through an entire OODA-loop cycle to figure out what to do.

I'd also call into question the wisdom and effectiveness of trying to implement any strategy that is 100% eyes out the window with audio cues only. Audio cues take a long time (multiple seconds) to generate precise information on distance, relative altitude, track, speed, orientation, yet much of this information can be important in the "Orient-Decide" part of the loop. Picking up a collision target visually is hard (as opposed to one that is not a threat and therefore has angular movement in the pilot's visual field). The pilot has to orient his gaze to the right location +/- about 2 degrees to pick up a target - peripheral vision isn't much help. With enough scanning around you may pick up the target, but getting into the right ballpark more precisely with the aid of a look at the display may in fact be a faster and more effective way to acquire a threat target visually.

I don't think TCAS is intended for RAs to be the first line of defense, rather, they are the last line. Being able to have most of the "Observe-Orient" part of collision avoidance mostly taken care of with traffic 5+ miles away is preferred, especially since most of the preemptive maneuvering will be with an Air Traffic Controller in the loop for TCAS-equipped traffic. Flarm and gliders instead of SSR/TCAS and jets present very different scenarios so direct comparisons are challenging, especially if you are talking about timing.

9B

jfitch

January 10th 16, 06:00 PM

On Saturday, January 9, 2016 at 11:54:33 PM UTC-8, Darryl Ramm wrote:
> On Saturday, January 9, 2016 at 11:07:04 PM UTC-8, jfitch wrote:
> > On Saturday, January 9, 2016 at 5:47:04 PM UTC-8, XC wrote:
> > > On Saturday, January 9, 2016 at 7:30:48 PM UTC-5, jfitch wrote:
> > > > On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> > > > <SNIP>>Let's make sure these numbers are based on some evidence.
> > > >
> > > > Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
> > > >
> > > > The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.
> > >
> > > More details about TCAS for comparison:
> > >
> > > 5 sec. is the maximum expected reaction time for a warning or RA. That is with the autopilot engaged and the pilot not actively engaged on the flight controls. The anticipated reaction time to reverse, increase or decrease vertical speed once the pilot is flying the machine is 2.5 sec.
> > >
> > > "Initial vertical speed reaction to a RA is expected within 5 seconds; maneuvering G forces should be similar to those felt when responding to an ATC clearance to climb or defend "immediately" (+/- 0.25 G change in load factor)." That doesn't sound too panicked.
> > >
> > > The TCAS display is selectable Above/Norm/Below. My company recommends normal in all phases of flight which gives +/- 2700 ft on the display. This is for aircraft capable of climbing or descending 6000 ft/min. "Above" can be selected in the climb which would give a view of aircraft 7000 ft above and 2700 ft below.
> > >
> > > Now this is a different system, I understand, but my point is that it is not cross referenced continuously as a source of SA. Rather, it is an alert system that provides traffic advisories (TA) as aircraft are getting to be a factor ("Traffic") and resolution advisories (RA) ("Traffic, Climb/Descend)"when action is required by the pilot. The audio alerts and warnings have priority and have been determined to be more effective than the instrument panel display for collision avoidance.
> > >
> > > Similarly, displaying all traffic on FLARM at these greater distances and relative altitudes is not required for SA or collision avoidance. In fact, spending too much time looking down at the display may be contrary to safety. Again, this discussion goes beyond collision avoidance and gets into pilots wanting to track other gliders for tactical reasons.
> > >
> > > XC
> >
> > In searching for the best anti collision system, few people hold out TCAS as the ideal. I have heard much more criticism of it than praise, the latter usually confined to "it's better than nothing". This is why the regulators and industry worldwide are moving as fast as they possibly can towards ADS-B, a system much more like Flarm. Before we decide that the metrics of TCAS are ideal or even adequate, we should ask why that system is being discarded in favor of one that shows all aircraft within 15 miles, all the time: position, altitude, and tail number. Going by that metric, the FAA has already decided that 15 miles range is the right answer. Even at 1000 mph closing speed, 15 miles gives over 50 seconds warning. I propose 50 seconds is the best supported number.
>
> Oh what a pile of utter nonsense. TCAS II *is* the gold standard in collision avoidance. ADS-B does not replace TCAS II in *any* way. Not a single FAA regulation currently or proposed allows for replacement of TCAS II mandatory carriage with any ADS-B product.
>
> TCAS II is not being discarded/abandoned for anything, including ADS-B anything. There is no technology that uses ADS-B for active collision avoidance similar to TCAS available as any RTCA standard and so nothing that can be build and no research projects that could be turned into such a standards any time soon. So at best anything based on ADS-B would likely be decades away. I have now idea where you are getting this 15 miles from. The ADS-B ground services hockey-puck diameter? That really has no direct relevance to TCAS. It is a stopgap layered on a complex dual-link mess.
>
> TCAS II version 7.1 (the current standard) makes use of ADS-B In data to reduce the activeTCAS II transponder interrogation rates and provide better long range tracking of targets (esp. without excessive RF congestion). These systems do not use ADS-B data to issue an RA, that is all determined by active TCAS II to transponder interrogation. One of the specific advantages of Change 7.1 ADS-B integration is improved long range (much longer than 15nm you mention) traffic display... which in USA Class A airspace they will be able to rely on every aircraft being quipped with after 2020.
>
> So not a single thing you stated is correct.

I should have said, "ADS-B is being incorporated into TCAS to make up for its shortcomings". According to reports, TCAS IV was abandon in favor of ADS-B enhancements. A couple of the main enhancements in question being accurate position, vector and ID information, precisely the things stealth advocates want to suppress. Whether we are talking about TCAS or ADS-B or ADS-B enhanced TCAS, there is not even a suggestion that the FAA thinks 5 seconds is adequate for anything but a last ditch panic maneuver.

There is a parallel in shipping collision avoidance, which depended on automated radar tracking aids for many years. This has been replaced in less than a decade by a GPS based digital network operated on VHF. No one I know wants to go back as it is far superior to radar tracking. In all of these systems, situational awareness is considered the first line of defense against collision, and automated warnings intended as a stop gap to cover cases where situational awareness was lost.

Charlie M. (UH & 002 owner/pilot)

January 10th 16, 06:50 PM

On Sunday, January 10, 2016 at 1:00:09 PM UTC-5, jfitch wrote:
> On Saturday, January 9, 2016 at 11:54:33 PM UTC-8, Darryl Ramm wrote:
> > On Saturday, January 9, 2016 at 11:07:04 PM UTC-8, jfitch wrote:
> > > On Saturday, January 9, 2016 at 5:47:04 PM UTC-8, XC wrote:
> > > > On Saturday, January 9, 2016 at 7:30:48 PM UTC-5, jfitch wrote:
> > > > > On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
> > > > > <SNIP>>Let's make sure these numbers are based on some evidence.
> > > > >
> > > > > Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.
> > > > >
> > > > > The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.
> > > >
> > > > More details about TCAS for comparison:
> > > >
> > > > 5 sec. is the maximum expected reaction time for a warning or RA. That is with the autopilot engaged and the pilot not actively engaged on the flight controls. The anticipated reaction time to reverse, increase or decrease vertical speed once the pilot is flying the machine is 2.5 sec.
> > > >
> > > > "Initial vertical speed reaction to a RA is expected within 5 seconds; maneuvering G forces should be similar to those felt when responding to an ATC clearance to climb or defend "immediately" (+/- 0.25 G change in load factor)." That doesn't sound too panicked.
> > > >
> > > > The TCAS display is selectable Above/Norm/Below. My company recommends normal in all phases of flight which gives +/- 2700 ft on the display. This is for aircraft capable of climbing or descending 6000 ft/min. "Above" can be selected in the climb which would give a view of aircraft 7000 ft above and 2700 ft below.
> > > >
> > > > Now this is a different system, I understand, but my point is that it is not cross referenced continuously as a source of SA. Rather, it is an alert system that provides traffic advisories (TA) as aircraft are getting to be a factor ("Traffic") and resolution advisories (RA) ("Traffic, Climb/Descend)"when action is required by the pilot. The audio alerts and warnings have priority and have been determined to be more effective than the instrument panel display for collision avoidance.
> > > >
> > > > Similarly, displaying all traffic on FLARM at these greater distances and relative altitudes is not required for SA or collision avoidance. In fact, spending too much time looking down at the display may be contrary to safety. Again, this discussion goes beyond collision avoidance and gets into pilots wanting to track other gliders for tactical reasons.
> > > >
> > > > XC
> > >
> > > In searching for the best anti collision system, few people hold out TCAS as the ideal. I have heard much more criticism of it than praise, the latter usually confined to "it's better than nothing". This is why the regulators and industry worldwide are moving as fast as they possibly can towards ADS-B, a system much more like Flarm. Before we decide that the metrics of TCAS are ideal or even adequate, we should ask why that system is being discarded in favor of one that shows all aircraft within 15 miles, all the time: position, altitude, and tail number. Going by that metric, the FAA has already decided that 15 miles range is the right answer. Even at 1000 mph closing speed, 15 miles gives over 50 seconds warning. I propose 50 seconds is the best supported number.
> >
> > Oh what a pile of utter nonsense. TCAS II *is* the gold standard in collision avoidance. ADS-B does not replace TCAS II in *any* way. Not a single FAA regulation currently or proposed allows for replacement of TCAS II mandatory carriage with any ADS-B product.
> >
> > TCAS II is not being discarded/abandoned for anything, including ADS-B anything. There is no technology that uses ADS-B for active collision avoidance similar to TCAS available as any RTCA standard and so nothing that can be build and no research projects that could be turned into such a standards any time soon. So at best anything based on ADS-B would likely be decades away. I have now idea where you are getting this 15 miles from. The ADS-B ground services hockey-puck diameter? That really has no direct relevance to TCAS. It is a stopgap layered on a complex dual-link mess.
> >
> > TCAS II version 7.1 (the current standard) makes use of ADS-B In data to reduce the activeTCAS II transponder interrogation rates and provide better long range tracking of targets (esp. without excessive RF congestion). These systems do not use ADS-B data to issue an RA, that is all determined by active TCAS II to transponder interrogation. One of the specific advantages of Change 7.1 ADS-B integration is improved long range (much longer than 15nm you mention) traffic display... which in USA Class A airspace they will be able to rely on every aircraft being quipped with after 2020.
> >
> > So not a single thing you stated is correct.
>
> I should have said, "ADS-B is being incorporated into TCAS to make up for its shortcomings". According to reports, TCAS IV was abandon in favor of ADS-B enhancements. A couple of the main enhancements in question being accurate position, vector and ID information, precisely the things stealth advocates want to suppress. Whether we are talking about TCAS or ADS-B or ADS-B enhanced TCAS, there is not even a suggestion that the FAA thinks 5 seconds is adequate for anything but a last ditch panic maneuver.
>
> There is a parallel in shipping collision avoidance, which depended on automated radar tracking aids for many years. This has been replaced in less than a decade by a GPS based digital network operated on VHF. No one I know wants to go back as it is far superior to radar tracking. In all of these systems, situational awareness is considered the first line of defense against collision, and automated warnings intended as a stop gap to cover cases where situational awareness was lost.

While I "mostly read" these discussions, I would like to say that the FAA is looking at mostly commercial traffic (when writing rules for distance & timing of TCAS/etc.) where you have 250KTS for each aircraft (500KTS closure, below 10K') and more speed higher.
Rarely do you have sailplanes doing 250KTS closure, let alone airspeed (maybe opposing ridge runs, western US big cloud streets), thus what the FAA is looking for in collision avoidance is just, "a wee bit different" than what sailplanes are looking for.

Granted, more time is better, more heads up time is better, basically we seem to have a "****ing contest" going on but since I'm not a current US contest pilot, I sorta just sit back and watch what is going on (so I have an idea on what to expect down the road).

If I could vote on a rule for "what to do with Flarm in a US contest", I would likely vote to:
-Reduce our range to 5KM (likely proposed US RC idea)
-Squash contest ID & "rate of climb" outside of 5KM
-Keep full info within 5KM to aid in collision avoidance per whatever Flarm can provide (yes, there will be cases that even the best algorithm gets befuddled....)

I'm speaking for myself, I'm NOT speaking for anyone else, nor do I have outside input to the US RC.

PS, I also understand that potential upcoming US FAA rules may make some of this moot, even current US contest pilots (with certified installed equipment) may make this whole discussion rather moot.
I also ask myself, "Why do some push their Flarm agenda so hard, do they want to change the sport today rather than wait until the FAA does it for them?!?!".

I don't know although I have my own ideas I won't really share.

January 10th 16, 09:03 PM

> Then point out all the time values not just the ones that seem to support your stance on stealth. TCAS Non threat traffic more than 6 miles away can be displayed to well over 40 miles away. Proximity intruder traffic less than 6 miles away fill in the diamond display(visual no audio) to get your attention and provide situation awareness to prevent surprise TA and RA alerts. Traffic Alerts (TA) for potential collisions will happen from 20-48 seconds to closest point of approach(collision) with a visual change to yellow diamond and audio "Traffic Traffic" Under normal conditions a TA will proceed an RA by 15 seconds which prepares the pilots for any required RA avoidance maneuver while giving time to acquire the target visually if possible. Resolution Advisories (RA) which TCAS deems an imminent collision threat with a time of closest approach of 15-35 seconds warns with a red diamond visual cue and audio avoidance commands (Climb Climb Climb, Monitor Vertical speed etc...) as well as the required vertical speed required for the 5 second maneuver you posted.
>
>
> TCAS uses these multiple steps of awareness from well over 40 miles away to try and prevent surprise RAs as well as to give crews the time required to scan visually for the traffic. I also find it very hard to believe there have been many instant RAs without the targets going through the normal threat scales of non threat, proximity, TA, RA, Clear of Conflict or at least some of them. Does it happen yes but it is not the norm.
>
> To suggest that your eyes are inside looking at the TCAS only because you are IFR is misleading. It gives you the fastest way of locating the direction and altitude of the potential collision traffic so you can then start looking visually for the traffic if your not in clouds. No one using TCAS gets a pop up TA and starts randomly visually scanning the sky hoping to see the traffic. It takes much longer than looking at the TCAS visual display for a split second to find out where the traffic is then back outside to find it visually.
>
> This is exactly the same method that FLARM uses with a scaled response to traffic threats as they get closer and are deemed a threat. Both TCAS and FLARM allow much better situational awareness of traffic. I would argue that FLARM stealth mode is exactly like the pop up surprise TCAS RA example you used. It should never happen as there is only 5 seconds to respond. TCAS users get the advantage of a computer giving an immediately calculated escape maneuver. FLARM users only have seconds to find the traffic visually to find out what to do.

Sorry to not have done my homework better. The 5 seconds reaction time from holding a cup of coffee to change in vertical speed is the one give in our book at work. It is 2.5 sec with a little bit more G (+/- 0.35 G) to increase, decrease or reverse vertical speed. I didn't have any of those other numbers ready when I posted last night. The reaction times can be inferred as the "get moving" time. Add seconds as necessary to make the extra decisions needed for FLARM. How many more do you need? 10 sec?

TCAS II is a different system with a different criteria for what is "close".. To find this you have to get beyond the seconds and look at the protected distances which are also part of the equation. They apply when aircraft are closing slowly.

5000-10000 ft MSL TA= 0.75 nm or 850 ft vertical, RA = 0.55 nm or 600 ft vertical
10000-20000 ft MSL TA= 1.00 nm or 850 ft vertical, RA = 0.80 nm or 600 ft vertical

So you have to read between the lines a little, granted, but the above distances can be used to explain what TCAS thinks is a close call. The warnings are designed so the aircraft never gets any closer than this.

I think (I hope) we can agree that gliders routinely fly together inside of these distances without creating a bad situation. The times involved would logically be different.

A couple of other points to make about TCAS. Our display range is 6 or 12 nm. It routinely is set to show aircraft +/- 2700 ft. So all the tracking stuff is going on behind the scene and yes, TA's and RA's outside of those distances are show. But proximate traffic is not show beyond 12 nm on our installation.

XC

smfidler

January 11th 16, 01:39 PM

This discussion tells me that we are, at best, still defining requirements. We should absolutely have not adopted (or run a test) contest in stealth. This is reckless and irresponsible. We have absolutely no idea what we are doing. We have absolutely no idea what Flarms average performance is.

We need to stop this child's play.

[email protected]

January 11th 16, 05:59 PM

On Monday, January 11, 2016 at 8:39:11 AM UTC-5, smfidler wrote:
> This discussion tells me that we are, at best, still defining requirements. We should absolutely have not adopted (or run a test) contest in stealth. This is reckless and irresponsible. We have absolutely no idea what we are doing. We have absolutely no idea what Flarms average performance is.
>
> We need to stop this child's play.

Based upon the express request of the originator above,you are on the wrong thread.
UH

smfidler

January 11th 16, 09:10 PM

OK I'll stop it here. ;-)

Jonathan St. Cloud

January 11th 16, 09:31 PM

On Monday, January 11, 2016 at 1:10:30 PM UTC-8, smfidler wrote:
> OK I'll stop it here. ;-)

Oh thank goodness, finally. So just to recap... we all decided to forgo this silliness of a nonexistent "stealth mode, the RC is going to mandate Flarm for all contests and we can polish up the tech vs No tech debate, next time something fun and useful comes along.

Charlie M. (UH & 002 owner/pilot)

January 11th 16, 10:20 PM

Some decided it, I didn't......

Again, while it may become a moot point down the road (due to FAA rules changes/exemptions), I feel we should limit "some new tech" until we find a "happy meeting ground" between tech and what we are trying to measure during a "soaring contest".

If the SSA rules we should do "team flying with ground crew info so we can compete on the worlds level", then most of this discussion is dead... "Que the dead horse beating".

Until then, we in the US follow the US rules, "full open Flarm" seems to go beyond this.
That's my take, waiting to see what happens next.

I've already cast my vote in this thread.

Andrzej Kobus

January 11th 16, 10:27 PM

On Monday, January 11, 2016 at 4:31:44 PM UTC-5, Jonathan St. Cloud wrote:
> On Monday, January 11, 2016 at 1:10:30 PM UTC-8, smfidler wrote:
> > OK I'll stop it here. ;-)
>
> Oh thank goodness, finally. So just to recap... we all decided to forgo this silliness of a nonexistent "stealth mode, the RC is going to mandate Flarm for all contests and we can polish up the tech vs No tech debate, next time something fun and useful comes along.

Jonathan, was this really necessary?

At minimum, I think we got some good test cases to work with and some scenarios to consider. I hope this dialog continuous into the future and whatever comes out of it can be acceptable to us all.

Complexity of this topic is high and different players (e.g. IGC, UK guys, and us) might have different requirements. It would be interesting to hear what folks at Flarm, who created the algorithms, wrote and tested the code, are comfortable implementing considering it is their product.

One thing is certain, we all want PowerFlarm to succeed as anti-collision avoidance system.

I have to admit, despite the fact that I was fairly critical of Flarm while we were going through PF growing pains in USA I would not imagine flying without it.

We have snow on the ground in NH. I miss the collision alerts :)

Andrzej

Charlie M. (UH & 002 owner/pilot)

January 11th 16, 10:41 PM

On Monday, January 11, 2016 at 5:27:26 PM UTC-5, Andrzej Kobus wrote:
> On Monday, January 11, 2016 at 4:31:44 PM UTC-5, Jonathan St. Cloud wrote:
> > On Monday, January 11, 2016 at 1:10:30 PM UTC-8, smfidler wrote:
> > > OK I'll stop it here. ;-)
> >
> > Oh thank goodness, finally. So just to recap... we all decided to forgo this silliness of a nonexistent "stealth mode, the RC is going to mandate Flarm for all contests and we can polish up the tech vs No tech debate, next time something fun and useful comes along.
>
> Jonathan, was this really necessary?
>
> At minimum, I think we got some good test cases to work with and some scenarios to consider. I hope this dialog continuous into the future and whatever comes out of it can be acceptable to us all.
>
> Complexity of this topic is high and different players (e.g. IGC, UK guys, and us) might have different requirements. It would be interesting to hear what folks at Flarm, who created the algorithms, wrote and tested the code, are comfortable implementing considering it is their product.
>
> One thing is certain, we all want PowerFlarm to succeed as anti-collision avoidance system.
>
> I have to admit, despite the fact that I was fairly critical of Flarm while we were going through PF growing pains in USA I would not imagine flying without it.
>
> We have snow on the ground in NH. I miss the collision alerts :)
>
> Andrzej

I give you "Two thumbs up" for risking yourself and making this thread. It has "flame war" written all over it.
As I stated before, I put in my "basic vote" which aligns with what you're proposing.

Since I'm not a "current US comp pilot", I have no say in what the US RC does/recommends.
I will still state my views as I feel they merit.

Yes, I like the added visibility that Flarm gives us (says the guy that could tell what brand gear door tape was on the glider that just passed over his head in a contest because the other pilot was fixated to others and not me going into a thermal....).
I don't want to give an advantage "outside of eyeballs & reading the local weather" to those that can afford the money & time to stack the deck in their favor.

Yes (yet again), FAA mandates down the road and ADS-x equipment currently installed may make this a moot point, but please, let's not just, "Go blindly down the road because it's easier" mentality.

Nuff said.