Paragraph 6 Simulated instrument flight
An aircraft shall not be flown in simulated instrument flight conditions unless:
the aircraft is fitted with dual controls which are functioning properly;
an additional pilot (in this rule called a “safety pilot”) is carried in a second control seat of the aircraft for the purpose of rendering such assistance as may be necessary to the pilot flying the aircraft; and
if the safety pilot’s field of vision is not adequate both forward and to each side of the aircraft, a third person, being a competent observer, occupies a position in the aircraft which from his field of vision makes good the deficiencies in that of the safety pilot, and from which he can readily communicate with the safety pilot.
For the purposes of this rule the expression “simulated instrument flight” means a flight during which mechanical or optical devices are used in order to reduce the field of vision or the range of visibility from the cockpit of the aircraft.