This is what we do at our Club:
What do I log? 1. There has been some discussion recently about what to log when licence holders are flying with FIs. To simplify and standardise matters, if the flight is conducted under the supervision of a FI (such as a Club Check), then the FI is the person who logs the time as Commander (P1C). The other pilot does not. If he/she wishes to log it at logs P1C U/S then the FI should endorse his/her logbook accordingly; if the FI is not content with the way the flight went and is not prepared to endorse the logbook, then the other pilot should log the time as P U/T. Revalidation or Renewal Proficiency Checks (which are only flown with an Authorised Examiner) follow these same guidelines.
What do I log? 2. When 2 qualified licence holders fly together in a Club aircraft, on occasion they may wish to share the flying. However, only 1 will be authorised as ‘Commander’ and that is the person who the Club holds responsible for the safe conduct of the entire flight. If the 2 pilots wish to share the flying, then each may log their own individual P1 time, but the total must be the same as the flight time. The designated Commander should also initial the logbook of the other pilot to confirm that the flight time logged by that pilot was so shared and should be named as Commander in the other pilot’s personal flying logbook.