The PIC of an aircraft shall ensure that before the aircraft approaches or enters an advisory airspace—
(a) two-way radio communication with the responsible ATSU is established on the designated radio frequency;
(b) if such communication is not possible, two-way radio communication is established with any ATSU which is capable of relaying messages to and from the responsible ATSU; or
(c) if such communication is not possible, broadcasts are made on the designated radio frequency giving information on the aircraft’s intention to enter the airspace, and such PIC shall ensure that, while the aircraft is within the advisory airspace and until it departs therefrom, a continuous radio watch is maintained on the designated radio frequency and that—
(i) such further two-way radio communication as the responsible ATSU may require, is established with any other ATSU which is capable of relaying messages to and from such responsible ATSU;
(ii) if such communication is not possible, such further two-way radio communication is established with any other ATSU which is capable of relaying messages to and from the responsible ATSU, as such responsible ATSU may require; or
(iii) if such communication is not possible, broadcasts are made on the designated radio frequency giving information on passing reporting points and when leaving the airspace concerned: Provided that—
(aa) an aircraft maintaining a Selcal watch while operating within an advisory route in the Johannesburg flight information region and whose Selcal call-sign has been communicated to the Johannesburg flight information centre, shall be deemed to be maintaining a continuous radio watch; and
(bb) in the case of a radio failure, a flight for which an air traffic service flight plan was filed and activated by an ATSU on receipt of a departure time, may continue in advisory airspace if the communication failure procedures specified in technical standard 91.06.16 of Document SA-CATS 91 are complied with.