On Sunday, October 21, 2012 10:03:48 PM UTC-7, Brad wrote:
On Oct 21, 8:28*pm, Ramy wrote:

On Sunday, October 21, 2012 6:52:17 PM UTC-7, wrote:

On Sunday, October 21, 2012 6:41:11 PM UTC-5, Evan Ludeman wrote:



On Oct 21, 7:35*pm, wrote:



On Saturday, October 20, 2012 5:52:55 PM UTC-4, Dave Nadler wrote:



On Saturday, October 20, 2012 5:30:05 PM UTC-4, Don Johnstone wrote:



... I was very uncomfortable with the concept of instructing



pilots to lessen the efficiency of an anti-colision assistance device.



Stealth mode in no way lessens the efficacy of FLARM anti-collision.



It gives you warnings when there is a collision hazard regardless.



Hope that is clear,



Best Regards, Dave



Dave,



it is clear, and while your statement is probably technically accurate, it isn't entirely correct. *Any mode that reduces the pilot's situational awareness also degrades safety to some extent. Stealth mode by definition does exactly that. *The OC fatality scenario is a case where stealth mode might not provide enough warning to assess the situation and take appropriate action, whereas the 'full' mode probably would. *Just my $0.02



Frank (TA)



See pg 19 of the PowerFlarm Dataport Specification for details about



how stealth mode works.



It's he *http://tinyurl.com/8ne9cjx



Stealth mode does not change the anti-collision functionality of



PowerFlarm at all. *You'll get the get the same 25 seconds warning,



which is plenty.



Evan Ludeman / T8



"Plenty" is interesting. Let's all remember, flarm is not a "collision avoidance" device. It is a "collision warning" device. You still have to find the other glider, avoid it, and not run in to anyone else while you're doing that. Don't just bank away from the collision threat, make sure there isn't a new collision threat.



If glider A is a collision threat, glider B is off to your side and not a collision threat, will flarm show glider B in stealth mode? No, I gather. *If you suddenly bank towards glider B to avoid glider A...



And it doesn't always give 25 seconds warning, especially if carbon fuselages are blocking signals. Gliders have collided when both had operating flarm systems. Norway and Uvalde.



A stealth mode is far from obviously a good idea, if it only shows imminent collision threats. *The operation and reliability of such a mode have to be really bulletproof. Which, given power flarm's recent history with range issues, software updates, antenna updates etc., would seem to be something one would want a lot of real world experience with. But how do we get real world experience and find out its actual limitations?



It's interesting how many reports we're getting of pilots who saw collision threats with flarm. But we obviously don't know about the failures until they hit each other. And how do we learn about the failures under stealth mode. Can of worms here.



John Cochrane



I agree with John. I find the situational awareness as important as the collision alert. Also, not sure where the 25 sec came from, but when I was on a head on with another glider at 17K both of us flying above 100 knots TAS, the warning we got was more like 10 seconds, just enough to react and bank away. We never saw each other until we banked away, but luckily we saw each other on flarm radar 5 miles away giving us plenty time to be alerted and be prepared to change course. I sure hope no one will fly in stealth mode.



Ramy



Ramy,



How did you know which direction to bank? I've not flown with the unit

enough to get a feel for what evasive moves to make. So far when I've

been warned I've seen the other aircraft and can react accordingly.



Thanks,

Brad

I should mention that we were also talking to each other on the radio. The whole time we were closing on each other I was waiting to see him but when the collision alert and the audio alarm started showing him at 12 ocklock same altitude I just decided the bank to the right while radioing to him that I am doing so, and he banked to the right as well. This was the first time for both of us to see each other, very eye opening as we both knew there is traffic ahead and were scanning for it yet we couldn't see each other as we were a non moving target. I figured banking right is the standard procedure with head on traffic, if not, it should be the protocol when flarm warns of traffic at 12 oclock. Diving or pulling my not work since both pilots may do the same thing, but both banking right will do the trick.

Ramy