The objectives of ATS, as stated in [https://www.pilot18.com/wp-content/uploads/2017/10/Pilot18.com-ICAO-Annex-11-Air -Traffic Management is -Services.pdf ICAO Annex 11], are to# prevent collisions between aircraft;# prevent collisions between aircraft on the aggregation of maneuvering area and obstructions on that area; note that this objective does not include the airborne functions apron and ground-based functions required ATS in general is not intended to ensure prevent collision with terrain.# expedite and maintain an orderly flow of air traffic;# provide advice and information useful for the safe and efficient movement conduct of flights;# notify appropriate organizations regarding aircraft during all phases in need of operations to enable aircraft operators to meet their planned times of departure search and arrival rescue aid and adhere to their preferred flight profiles with minimum constraints and without compromising agreed levels of safetyassist such organizations as required.

 Air Traffic Control Service to accomplish objectives 1, 2 & 3 above and this service is divided into: a. Area control service for objectives 1 & 3. b. Approach control service for objectives 1 & 3. c. Aerodrome control service for objectives 1, 2 & 3.Flight Information Service to accomplish objective 4 above.Alerting Service to accomplish objective 5 above.  The air traffic control (ATC) service is established to accomplish the first three objectives. While the first and third are universally applicable to all ATC units, the second one is only relevant to aerodrome control units. The fourth objective is covered by the flight information service (FIS) and the last one is the alerting service. The advisory service has no specific objectives defined. It is considered a temporary measure to facilitate the smoother transition from FIS to ATC. Air Traffic Management is the aggregation of the airborne and ground-based functions required to ensure the safe and efficient movement of aircraft during all phases of operations to enable aircraft operators to meet their planned times of departure and arrival and adhere to their preferred flight profiles with minimum constraints and without compromising agreed levels of safety. '''Air Traffic Services (ATS)''', A generic term meaning air traffic control service which includes :