"Bill Daniels" wrote in message news:sofkc.273
2, If one of these represents a collision danger, the device should give a
bearing. The device need only determine that the target is at or near the
same altitude, the distance is closing and the relative bearing is nearly
constant. If there is only 1% chance of an actual collision, that would get
my undivided attention.

And that's the part that really scares me! It's is far to easy to
focus on a known threat to the total exclusion of searching for the
unknown threats. I've seen far too many airplane drivers place full
reliance on ATC traffic calls and more recently on TCAS advisories.
As glider pilots we face the same problem when joining thermals. It's
far too easy to narrow one's scan to all the known traffic, to plan
the entry based on that knowledge, and then to be surprised by another
glider that could have been seen with a wider scan.

Collision warning devices can increase safety if all gliders have them
and they are working. When only a few gliders are equipped there
could be a reduction in safety.


Andy