Carriage of a flight engineer

Where a flight engineer is required by the terms of the certificate of airworthiness to be carried in an aircraft and a separate flight engineer’s station is incorporated in the design of the aircraft a flight engineer, qualified under the terms of his licence to act in that capacity in the aircraft, shall be carried and assigned for duties only at the said station unless the operating crew includes a person, licensed for flight duties in another capacity and being also the holder of the appropriate flight engineer’s licence who could, without interference with his normal duties, carry out satisfactorily the duties also of flight engineer, in which case that person may act in the capacity of