Originally Posted by IO540
Q1: is it legal, in UK airspace?
Q2: can the P1 pilot log it and, if so, what as?
The pilot who is appropriately rated for the conditions ("P2 seat pilot") must act as pilot-in-command for the flight. He should log it as such.
The other pilot ("P1 seat pilot") is not "acting as a member of the flight crew required by or under [the ANO] to be carried in an aircraft". I therefore cannot see a requirement for him to hold a flight-crew licence.
Part 61.51 allows pilot-in command time to be logged when a pilot
(i) Is the sole manipulator of the controls of an aircraft for which the pilot is rated;
and instrument time when he
operates the aircraft solely by reference to instruments under actual or simulated instrument flight conditions.
The "P1 seat pilot" should therefore log time accordingly, as required by the FAA.