1496 INTERNATIONAL AGREEMENTS OTHER THAN TREATIES [55 STAT. c) that there be provided adequate frequencies for local aeronautical communications at route terminals and intermediate airports. d) that it be permitted, in the meantime, to continue the use of the frequencies 5692.5, 5405, 3082.5, 2870 and 1638 kc which are actually assigned to aircraft and aeronautical stations on the Inter-American route. IX AIR-GROUND COMMUNICATIONS Considering: 1.- that it is essential to institute a security organization (which may involve coordination between various agencies, both govern- ment and non-government in nature) comprising services for radio-communication, radio-guidance, traffic control and the safe-guarding of aircraft; 2.- that it will result in confusion if a multiplicity of ground aero- nautical stations at one time take on the responsibility of com- munications concerning the security of a given aircraft, and that this will also result in radio disturbances; 3.- that under certain conditions it may be difficult to keep watch simultaneously on more than one radio frequency on board aircraft; 4.- that it is necessary to economize in the number of frequencies employed and in their use; it is recommended: a) that each of the various air traffic lanes which can be considered as constituting an Inter-American air route, in the sense in which this expression is defined for the distribution of the radio frequencies in the General Radio Regulations of Cairo, be divided into sectors of control, each sector being allocated to a station serving such route; b) that, in principle, the boundary of a sector of control is the middle of the distance separating the station to which such sector is allocated, from the station controlling the following sector of the same lane; c) that, for a given flight, the exact point where the transfer of com- munications control from one station to the next will be effected is determined by an agreement between the ground stations concerned, and the aircraft. X POINT-TO-POINT COMMUNICATIONS OF THE AERONAUTICAL SERVICES Considering: 1.- that the establishment of sectors of control might necessitate the employment of a rapid and adequate fixed communications service between control stations;
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