must be designated by the operator to do this. Where I come from this is interpreted as a Training Captain who is training another person for command. A Line Captain may give the F/O the sector as PF, and he may make most of the decisions on that sector, but he is still the F/O.
The NZ notion of command practice could be something else.
That's exactly how Eagle does it. Any line F/O may receive/conduct command practice under the supervision of any line captain as long as both crew members have completed their 3 month check after initial clearance to line in their respective role. i.e. a new captain (<3mths experience in role) may not supervise command practice, and a new co-pilot (<3mths experience in role) may not receive/log command practice.
The captain does not have to sign each entry in the Co's logbook, because the daily trip record (kept by company) records whether the sector was flown as Command Practice.
S2K