Hi wiggy,
Thanks for your input - do you have any sort of reference for that information? Or does anyone else?
I've talked to some guys who log every hour regardless of role - 'because they are a required crew member' etc, even if they're augmenting and on a rest period. Some others do the same as you have said, but treat the operating FO the same as the operating captain - so the FO logs rest time too on an operating sector. Some others just log the time at the controls, whatever their role.
I'm not sure whether this issue is actually specified by ICAO/EASA, as it is a separate issue to the FTL limitations. Anyone know?