On Tuesday, December 22, 2015 at 2:15:16 PM UTC-8, wrote:
SNIP Not trying to be difficult but I must be missing something. If they're that close to you (i.e., within 2 km), they're visible even with Stealth..


From the Flarm documents, V6.0 page 19 (maybe this has changed?):

"Targets with enabled “Stealth Mode” are only displayed.... if they meet at least one of the following requirements:

- target is a threat

- target is within 100m horizontal and 50m vertical
- target is within 2000m horizontal and 300m vertical and within ±45° of own flight track."

So the guys going your way - the ones ND is going to pull up sharply into - you don't even know are there. They aren't a threat because they are paralleling your course. Even if they are close enough to appear, their relative altitude is intentionally wrong.

Now I am going to repeat for the 20th time or so, I don't believe Flarm is a huge increase in safety. It is a big sky and most accidents are spin/stall, not head on. I don't even call my Flarm an anti-collision device, I call it an in-flight entertainment system. But certainly beyond a doubt, it improves situational awareness always, and particularly in the scenario described. On The White Mountains and the Sierra convergence lines, I don't think there have been any head-ons than I can recall. Its a big sky. But plenty of people have had to change their underwear at the end of the day, I can assure you. It was enough of a concern that a rather elaborate procedure was devised in the area, reserving a radio frequency and involving reporting points etc., all of which seemed pretty ineffective, while non-stealth FLARM pretty much solves the problem completely and with no distraction.