Mike Schumann wrote:
How would transponders have "negative" results if mandated for everyone in
aviation? The only argument against transponders is the cost.

The cost is certainly one negative result. A lot of people own machines
for which the cost of instaling a transpoder would make up a significant
fraction of the total value of the aircraft. A lot of owners couldn't
easily absorb such a cost. I don't know if there are other downsides, but
the cost shouldn't simply be dismissed.

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.

It will *help* protect you, but ATC isn't perfect. Mid-air collisions have
occurred between aircraft equipped with transponders and under ATC
control. All things being equal I'd certainly rather have one than not,
but it won't always save you.

--
Michael Ash
Rogue Amoeba Software