Canadian Aviation Regulations

602.136 Subject to sections 602.137 and 602.138, where an aircraft is equipped with radiocommunication equipment, the pilot-in-command shall ensure that

• (a) a listening watch is maintained on the appropriate frequency; and

• (b) where communications are required, communication is established with an air traffic control unit, flight service station or community aerodrome radio station, as applicable, on that appropriate frequency.