Originally Posted by
number_6
IPC is South America (100% sure of that). The PPT question has come up and I recall that there was a big problem with PPT (other than no service westward from PPT). Perhaps IPC-PPT was considered an ocean crossing; or it may have been the "no surface crossing of the pacific or atlantic ocean" rule (which meant you could not buy a separate non-oneworld ticket to "cross" the pacific), requiring return to SCL. Definitely some rule that made PPT very unattractive (but rules have changed so you'll have to research the current situation further, just be wary of initial findings).
PPT is unattractive because it is classed as SWP not South America. As the only OW flight from PPT is PPT-IPC-SCL and you cannot backtrack between continents then you are forced to have a surface segment PPT-somewhere in SWP or vv, on a xONEx. On Global Explorer (the OW mileage based RTW) the problem does not arise because TN is one of the allowed non-OW airlines on that fare. TN flies PPT-SYD or AKL.