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The term ANS (Air Navigation Service) include ATM (Air Traffic Management), CNS (Communication, Navigation and Surveillance), Meteorological Services (MET), Search and Rescue (SAR) and Aeronautical Information Service/Aeronautical Information Management (AIS/AIM). These services are provided to air traffic during all phases of aircraft operations (En-route, Terminal and Aerodrome).

  • ANS comprises of three directorates
    1. Operations Directorate
    2. CNS Engineering Directorate
    3. Flight Calibration Directorate

Communication Operations branch within operations directorate is responsible for Planning and coordination for implementation of procedures of Aeronautical Telecommunication Network (ATN) / ATS Message Handling System, Domestic & International speech circuits, En-route High Frequency Air Ground communication and to coordinate with PTA (Pakistan Telecommunication Association) and FAB (Frequency Allocation Board) for the purpose of licensing and safeguard of Aviation frequencies.

Communication operation branch is primarily providing:
  1. Aeronautical Fixed Service

    The aeronautical fixed service comprises the systems (ATS-MHS) and applications that are used for ground-ground (i.e. point-to-point and/or point-to-multipoint) communications in the international aeronautical telecommunication service.

    The ATS (air traffic services) message handling services (ATS-MHS) application allows ATS messages to be exchanged between service users over the aeronautical telecommunication network (ATN) internet communication service (ICS). The inter-centre communications applications enable the exchange of information between air traffic service units over the aeronautical telecommunication network (ATN) internet communication service (ICS), in support of notification, coordination, transfer of control, flight planning, airspace management and air traffic flow management.

    The following categories of message are handled by the ATS-MHS:

    1. distress messages;
    2. urgency messages;
    3. flight safety messages;
    4. meteorological messages;
    5. flight regularity messages;
    6. aeronautical information services (AIS) messages;
    7. aeronautical administrative messages;
    8. service messages.

    The network architecture of ATS Message Handling System with its International and Domestic Data links and Media are shown in figure below:

  2. Aeronautical Mobile Service

    The aeronautical mobile service comprises High Power HF-R/T (High Frequency-Radiotelephony) equipment reserved for communication relating to the safety and regularity of flight, primarily along national or international civil air routes.

    The aeronautical stations of a radiotelephony network assists each other in accordance with the network principles, in order to provide the air-ground communication service required by the aircraft flying on the air routes for which the network is responsible.

    During its tenure of primary guard, HF-R/T ground station is:

    1. responsible for designating suitable primary and secondary frequencies for its communications with the aircraft;
    2. receive all position reports and handle other messages from and to the aircraft essential to the safe conduct of the flight;
    3. be responsible for the action required in case of failure of communications;
    4. be responsible for transfer of primary guard from one station to the next, normally take place at the time of the traversing of flight information region or control area boundaries, however, where communication conditions so demand, a station may be required to retain primary guard beyond such geographical boundaries or release its guard before the aircraft reaches the boundary.

  3. Aeronautical Broadcasting Service

    The aeronautical broadcasting service comprises VOLMET Broadcasting equipment reserved for transmission of Meteorological information relating to air navigation. Specific time-slots have been allocated to Pakistan for VOLMET Broadcast on designated frequencies.

    Time Slots:

    • Hour + 15 to Hour + 20
    • Hour + 45 to Hour + 50
    • Day Frequency:11387 KHz
    • Night Frequency: 2965 KHz
    • Day/Night Frequency: 6676 KHz
    In addition to above mentioned Services, communication operations branch is also responsible for;
    • transmission of NOTAMs according to ICAO Annex 15 (Aeronautical Information Services).
    • transmission of IOU (Incident Occurrence and Unserviceability) report using SDCPS (Safety Data Collection and Processing System).
    • to carry out the necessary coordination with Frequency Allocation Board (FAB) and Pakistan Telecommunication Authority (PTA) for the purpose of:
      • licensing of Aviation frequencies
      • to ensure Aeronautical Radio Navigation Service continue to work without any interference from other sources
      • and to safeguard Aeronautical Radio Navigation frequencies allocated for aviation use

    Communication Operations branch is also transitioning from present AMHS/AFTN networks towards CRV (Common Aeronautical Virtual Private Network) as per ICAO standards to ensure reliability of the Network and to become the early participant of SWIM (System Wide Information Management) which will complement human-to-human with machine-to-machine communication to improve ATM data distribution and accessibility.

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Copyright Pakistan Civil Aviation Authority - 2019