On Tuesday, March 27, 2012 12:04:13 AM UTC-4, Mike Schumann wrote:
Why the hostility to any suggestion of using ADS-B as a collision avoidance technology? ... It is clearly possible to extend the functionality of these applications to intelligently provide warnings of potential collision threats. This is what FLARM does. It is also what TCAS does. Neither of these systems have a monopoly on this functionality.

You're missing some important points:

(1) ADS-B messages, whether via UAT or 1090, contain
only a current position and velocity vector. This is
quite different from FLARM, which broadcasts the expected
position over the next 20 seconds, taking into account
type of aircraft and recent history.

Why do we care ? Because if you have the detailed
info (for example, think about a glider circling),
you can be more precise about when there is really
a collision hazard. Without this info, you need to
use a big bubble, and you'll get lots of false
alarms for gliders maneuvering close together.

Works great for powered aircraft that don't want
to be close together, and generally fly straight.
Not helpful for gliders !

(2-27) Reread Darryl's posts carefully ;-)

Hope that helps,
Best Regards, Dave