T o d d P a t t i s t wrote:
Mark Hansen wrote:


The difference, in my opinion, is in who is taking responsibility
for the planning, nav, control, etc. of the flight. In the case where
there are two pilots sharing the duties, is either one really taking
responsibility?


Yes. The pilot acting as PIC takes responsibility.


I know they can decide in advance who will be PIC,
but when you get right down to it, only one person really planned
that flight; only one person really flew it; only one person really
landed, etc.


The FAR's are quite clear. If you are acting as PIC, these
are your responsibilities. You should not accept them
lightly.

A flight has exactly one PIC. That person is the one responsible for
the safe conduct of the flight and is the one that will get sued when
something bad happens. I'm not sure the term "acting PIC" appears in
the FARs -- can someone quote the definition for me?