A person's flight time as a flight engineer is:
(a) if the person is a flight engineer--the duration of a flight during which the person performs the duties of a flight engineer; and
(b) if the person is a flight engineer instructor--the duration of a flight during which the person exercises the privileges of his or her flight engineer instructor rating; and
(c) if the person is a flight engineer examiner--the duration of a flight during which the person exercises the privileges of his or her flight engineer examiner rating; and
(d) if the person is the holder of a cruise relief flight engineer type rating--any time spent performing the duties of a flight engineer during flight.