GM1 ATS.TR.105(b) Divisions of the air traffic services

AIR TRAFFIC ADVISORY SERVICE

(a)     The air traffic advisory service within airspace class F should be provided with the objective of making information on collision hazards more effective than it would be in the mere flight information service provision.

(b)     The air traffic advisory service may be provided to aircraft conducting instrument flight rules (IFR) flights in advisory airspace or on advisory routes (class F airspace), specified by the State concerned.

(c)      Air traffic advisory service does not afford the degree of safety and cannot assume the same responsibilities as air traffic control service in respect of the avoidance of collisions, since information regarding the disposition of traffic in the area concerned available to the unit providing air traffic advisory service may be incomplete.

(d)     The efficiency of air traffic advisory service will depend largely on the procedures and practices in use. Its establishment in line with the organisation, procedures and equipment of area control service, taking into account the basic differences of the two services, will help to ensure a high degree of efficiency and promote uniformity in the various provisions of air traffic advisory service. For example, exchange of information by the units concerned on the progress of an aircraft from one advisory area into an adjacent control area or terminal control area (TMA), and vice versa, will help to relieve pilots from repeating details of their flight plans already filed; also, use of standard ATC phraseology, preceded by the verbs ‘suggest’ or ‘advise’, will facilitate the pilot’s understanding of air traffic advisory service intelligence.

(e)     Air traffic services units providing air traffic advisory service:

(1)     advise the aircraft to depart at the time specified and to cruise at the levels indicated in the flight plan if they do not foresee any conflict with other known traffic;

(2)     suggest to aircraft a course of action by which a potential hazard may be avoided, giving priority to an aircraft already in advisory airspace over other aircraft desiring to enter such advisory airspace; and

(3)     pass on to aircraft traffic information comprising the same information as that prescribed for area control service.

(f)      The criteria used as a basis for action under points (e)(2) and (e)(3) should be at least those laid down for aircraft operating in controlled airspace and should take into account the limitations inherent in the provision of air traffic advisory service, navigation facilities and air-ground communications prevailing in the region.