tt01,
Yes, can do ICUS (which is co-pilot time) or co-pilot on a single pilot aircraft, metro, B1900, B200 it would be required to have two pilots for RPT if more than 10 seats, single pilot aircraft.
As long as your a designated crew member on the flight, you would be a crew member other than the PIC, which is co-pilot.
Could be in a C150 or a 747-400, a second officer in QF will log co-pilot time for the entire flight in the bunk or at the controls, the PIC also logs PIC if at the controls or in the bunk.
