Autopilot U/S then 2 pilots required by CASA = co-pilot time.
Any other "single pilot" aircraft no co-pilot time loggable.
In the case of customer requirement for 2 pilots then only PIC logs time while both log duty time. [same if they answered phone or refueled airdraft etc.]
If command pilot is an instructor then dual may be possible - but on a charter training MAY not be possible!
