(1) In the case of a multi-crew aircraft—
(a) each crew member shall be at his or her assigned station or seat, properly secured by all seat belts and shoulder harnesses provided, during take-off and landing and whenever deemed necessary by the PIC in the interests of aviation safety: Provided that the shoulder harness of a flight crew member not occupying a pilot seat may be unfastened if it interferes with the performance of his or her duties, but the seat belt must remain fastened;
(b) each crew member shall keep his or her seat belt fastened while at his or her assigned station, during phases of the flight, other than the phases referred to in paragraph (a);
(c) each flight crew member required to be on flight deck duty, shall be at his or her assigned station, during take-off and landing;
(d) all flight crew members on flight deck duty shall remain at their assigned stations during all phases of the flight other than the phases referred to in subparagraph (c): Provided that—
(i) a flight crew member may leave his or her assigned station, in the course of the performance of his or her duties with regard to the operation of the aircraft or for physiological needs; and
(ii) at least one suitably qualified pilot remains at the controls of the aircraft at all times; and
(e) the PIC or, where applicable, the operator shall ensure that flight and, if applicable, cabin crew members do not perform any activities during critical phases of the flight other than those required for the safe operation of the aircraft.
(2) In the case of a single-pilot aircraft, the PIC shall, during all phases of the flight, remain at the controls of the aircraft.