Mike Schumann wrote:

Having a transponder is not a panacea, in that it will not protect you from
a 172 or other VFR traffic that doesn't happen to see you, either due to a
lack of attention, or due to the inherent difficulty of seeing other
traffic. However, it should protect you from IFR traffic that is under ATC
control.


"Should"?

ATC _may_ give traffic information involving VFR traffic if they have
time. In other circumstances "protection" would come from the fact that
the IFR traffic _may_ have TCAS.

Mandating transponders is only a partial solution. Until every aircraft
also has a collision avoidance system of some type TCAS, PCAS, etc., the
regulatory push for more, and more expensive, equipment will never stop.
And in fact it will not stop until we have positive control of all
aircraft at all times in all places. We do not want to go there.

If the traffic that worries you is likely to have a transponder, then
spend a few hundred bucks and get a PCAS unit so you know where that
traffic is. And whether you add such equipment or not, learn how to scan
visually. It isn't something that comes naturally, even though you think
you are doing a great job. When you operate with a PCAS for a short
time, you will find out how much traffic you've been missing. As always,
we don't know what we don't know.


Jack