The truth about Flarm Stealth and Competition definition...

On Monday, January 4, 2016 at 3:16:36 PM UTC-8, XC wrote:
You need a better tactical display. No one I know tracks gliders for 4 minutes. You take a one second glance at the display and notice that there are 4 gliders the direction you are headed. A minute later another one second glance shows that one has headed off so there are still three. 2 minutes later another 1 second glance confirms that the 3 gliders are now pretty close, headed the opposite direction, and you should be looking for them that direction. You opt to alter course slightly right. A minute later a one second glance shows that your course alteration put the 3 other gliders safely to your left with no possibility of a conflict or Flarm alert. Situational awareness is only useful if you use it. You now have 4 seconds total heads down time spent over 4 minutes to completely eliminate any conflict with 4 other gliders with no other tactical benefit.

I am not believing you when you say you are looking at your display 4 seconds out of every 4 minutes.

The level one warnings begin to go off 13-18 seconds before a collision would happen. They are independent of the any stealth mode setting. That's a long time to make the small flight path adjustment necessary to avoid another glider. They are really pretty good but not perfect. Layer on top of that 2 km radius (going to 5 km now) and plus or minus 300 meters and you have all the situational awareness that is necessary.

The ongoing overstatements about degraded safety are folks who want to use open FLARM tactically (or, for the fun/learning of watching what others are doing.) Let's talk about that if you want to but let's not continue turn that into a safety argument.

XC

You may believe as you like. I probably look at the display somewhat less than 1 second/minute on average. My point is to look at and assess every glider on the display takes very little time, no more than one second, on a good display. Perhaps you have a poor one.

The 13 - 18 seconds you talk about is under ideal conditions. This is provably not the case in all situations. I have played around with friends to see just how close we can get before getting a warning and it is damn close under some circumstances. 2-3 seconds from potential impact. Come fly with me and I will prove it. These are not obscure situations, but ones you might easily find yourself in through a loss of situational awareness. This is why I concur with others who say that the situational awareness aspect is 80% of the value.

In stealth mode (and I assume the vaporware competition mode, but who knows?) you DO NOT get all of the situational data within 2, or 5 km. Read the spec. Altitude, track, and speed are not available until you get a collision warning. ID is not available ever. You literally do not know if a glider is coming or going.

I have been quite up front in saying that I want to use Flarm as an entertainment and educational tool. It's tactical use is quite limited (I have tried), and while it is a great safety tool, it protects against only a very rare event. I would say instead that the ongoing comments about heads down time is being made by those with a religious argument against Flarm technology who want to perpetuate the current status quo of tactics without objective reason. Let's not turn that into a safety argument.

One change that would make me and some others happier, is to make stealth non-reciprocal. That is, if you are flying in stealth it works as it does now, but if I am not I see everything. Since stealth is implemented on the receiving side, this would be easy to do and as risk free as a firmware change can get. In a Flarm and stealth mandated contest, you can still check to see if anybody in the contest cheated from the IGC file. But you would not be affecting everyone in the area, who may not even know a competition is going on.

On Monday, January 4, 2016 at 11:01:47 AM UTC-8, XC wrote:

Is there really a benefit of tracking a glider on your FLARM display for 4 minutes? Take a situation where there are 4 other gliders in your proximity. Keeping track of them all continuously with FLARM is a lot of heads down time. A lot of the gliders are more than 1000 feet difference in altitude and are no collision threat. Having all that displayed clutters the important info so is really only of tactical benefit.


I think 4 minutes was meant as part of a general visual scan rather than continuously fixating on the display. A scan that returns to the display within about 1/2 the lead time you'd expect to have for a target seems reasonable. If you only scan at the maximum lead-time a target can sneak in pretty close before you pick it up.

Four minutes of situational awareness lead time means scanning every minute or two. One minute of lead time means scanning every 30 seconds and 10 seconds of lead time would require you to have your head down pretty much continuously if you were concerned about nasty surprises. If you want to just wait for a target to become a collision threat and react to the collision alarm then by definition maintaining situational awareness to prevent conflicts is not part of your approach.

Because the "wait for the alarm to go off" makes some of us uncomfortable - the OODA loop is just too long with Flarm alarms in some cases - we prefer to keep track of aircraft in a bigger envelope before they get to alarm mode. Doing that is easier if you don't have to keep going back to the display to see what's new. For instance, I scan more frequently running cloud streets and convergence lines - particularly if I know there is traffic likely ahead because of an out and back course configuration, etc. I know that converging traffic can come up in a hurry and I want to be ahead of it if I can.

9B

On Monday, January 4, 2016 at 2:12:01 PM UTC-8, Andy Blackburn wrote:
SNIP
Because the "wait for the alarm to go off" makes some of us uncomfortable -

I'll go further than that. In my experience a Flarm warning means someone is really close. In my opinion an unexpected flarm warning means you screwed the pooch. Luck or Flarm saved your ass and his. You should really consider changing how you fly. One part of that might be turning off stealth mode and taking a glance at a good tactical display once in awhile.