Does anyone know any details of the history of logging PIC vs. serving
as PIC. I assume at one point you logged PIC anytime you served as PIC
and that the FAA changed it for some reason. Does anyonw know..
1) When did this change happen
2) What prompted it?

I'm thinking about writting a "logging PIC vs serving as PIC" article
for our club and am looking for some historical understanding.
-robert, CFI