GEN 3.4 Communication services
1 Responsible service
The responsible service for the provision of telecommunication and
navigation facility services in Somalia is the Somali Civil Aviation Authority
(SCAA).
The service is provided in accordance with the
provisions contained in the following ICAO documents:
-
Annex 10 — Aeronautical Telecommunications
-
Doc 8400 — Procedures for Air Navigation Services — ICAO
Abbreviations and Codes (PANS-ABC)
-
Doc 8585 — Designators for Aircraft Operating Agencies,
Aeronautical Authorities and Services
-
Doc 7030 — Regional Supplementary Procedures
-
Doc 7910 — Location Indicators
2 Area of responsibility
Communication services are provided for the entire territory of Somalia
including its territorial waters as well as the airspace over the high seas within the
Mogadishu FIR.
3 Types of service
3.1 Radio navigation services
NIL
3.2 Voice/Data link Services
Voice Service
The aeronautical stations maintain
a continuous watch on their stated frequencies during the published hours of
service unless otherwise notified.
An aircraft should normally
communicate with the air-ground control radio station that exercises control in
the area in which the aircraft is flying. Aircraft should maintain a continuous
watch on the appropriate frequency of the ATS station and should not abandon
watch, except in an emergency, without informing the control radio
station.
Data Link Service
The messages to be transmitted
over the Aeronautical Fixed Service (AFS) are accepted only if:
- they satisfy the requirements of ICAO Annex 10, Vol. II, Chapter 3, 3.3;
- they are prepared in the form specified in ICAO Annex 10;
3.3 Broadcasting service
NIL
4 Requirements and conditions
The requirements of Communication,Navigation and Surveillance and the
general conditions under which the communication services are available for
international use, as well as the requirements for the carriage of radio equipment, are
contained in GEN-1.5.
Additionally, caution is hereby advised due to unreliable Mogadishu FIC HF
communication. Pilots are requested to ensure appropriate mitigation measures including
the use of:
SATCOM INMARSAT CODE:466601
FIC Telephone Numbers-Tel:+25261857390, +2521857391, +2521857392, +2521857393, +252613350047, +252623350047 and or rely via the airline
operations unit or other ACFT or other ATS units as may be applicable.
5 RT procedures at Unmanned Aerodromes
All aircraft operating at, or into, aerodromes which no Air Traffic
Service is provided must broadcast their position and intentions on VHF frequency 127.45
MHz before landing and takeoff.
Initial call when in-bound:
- All stations (name of aerodrome)...x2
- Callsign and type of aircraft
- Direction from which the aircraft is inbound
- EET in minutes to a position in the circuit or overhead
- Any other useful information
- Position at which the next call will be made
In the circuit, overhead or on the
manoeuvring area:
- (a) and (b) above
- Present position
- Intentions of the Pilot in Command
- Position at which the next call will be made. This will normally
be the next position in the circuit or on the manoeuvring area.
Note 1 : An aircraft may not move into the landing area in use without
broadcasting its intention to do so and ensuring that there is no other traffic
which has right-of-way over it in that area.
Note 2 : All aircraft should try to keep the landing area in use as
free as possible. Habits such as doing power checks in that area should be
avoided.
6 Telecommunication Channels
The Aeronautical Fixed service (AFS) is provided in AFTN/AMHS formats for
the exchange of messages and /or digital data between Aeronautical stations and other
specified AMHS addressees having the same or compatible communication
characteristics.The AFS service is supplemented by SITA which acts as a back-up means of
communication when there is system failure. The services conform to ICAO procedures as
detailed in ANNEX 10 Vol II (Aeronautical Communications)
and provided through VSAT (very small aperture terminal) communication. As indicated in
figure 1 below the service is only connected to the rest of the world through Nairobi
communication center. Other domestic connections are yet to be implemented.
The AFTN, AMHS, SITA, E-MAIL and office telephone addresses for
Aeronautical communications (AEROCOM Office) are as stated below;
7 CPDLC AND ADS-C
7.1
General
7.1.1 Data link services is available to FANS1/A equipped
aircraft operating in the Mogadishu FIR.
7.1.2 Controller Pilot Data Link Communications (CPDLC) and
Automatic Dependent Surveillance- Contract (ADS-C) data link applications will be
used to provide services to FANS 1/A equipped aircraft, in both continental and
oceanic area as a secondary means of communication.
7.1.3 Participating CPDLC equipped Aircraft will be
requested by Mogadishu FIC in Somalia to log on HCSM-AFN LOGON address for Mogadishu
FIR.
7.2
CPDLC services to be provided in Mogadishu FIR
7.2.1 CPDLC is implemented in Mogadishu FIR initially to
facilitate provision of flight information services and alerting services, covering;
- Controller to Pilot uplink of traffic information.
- Pilot to controller downlink of position reports and traffic
information requests.
- Free text as a supplement to pre-formatted message
elements.
Note: The use of free text message elements shall
be restricted to non-routine and emergency situations.
- Alerting services and Emergencies
7.3
ADS-C Services to be provided in Mogadishu FIR
7.3.1 ADS-C will be used for the following services;
- Automatic reporting by the aircraft Flight Management System
(FMS) of aircraft position and intent Information.
- The FMS will report the required information in accordance
with parameters selected by ground system.
- Alerting services and Emergencies
7.4
Log on Procedure
- The AFN LOGON address for Mogadishu FIR is HCSM. To avoid
automatic rejection on the LOGON, the flight identification and aircraft
registration used by the pilot in the LOGON process must be identical to the
flight identification and registration filed in the flight plan.
- Standard pre-formatted message elements will be used whenever
possible except for Air Traffic Services provision messages. Free text messages
SHOULD ONLY be used when an appropriate pre- formatted message element does not
exist or to supplement the pre-formatted message element. LOGON request must be
received from the aircraft before any data link connections can be initiated by
the ground system. This is achieved via the ATS Facility Notification (AFN)
LOGON process to be initiated by the pilot in accordance with company
procedures.
- Aircraft requesting data link services inbound to Mogadishu FIR
are required to automatically/ manually LOGON onto HCSM 10 minutes prior to
estimate time for entering the airspace.
- Data link equipped aircraft departing from aerodromes within the
Mogadishu FIR and operating from FL245 and above shall LOGON to HCSM as soon as
possible after departure. Pilots who are unable to establish data link
connection are to inform ATC on HF/SATCOM communications
7.5
CPDLC Application Procedure
- Aircraft having established data link connections will maintain
CPDLC as the secondary means of communication. CPDLC will be used for provision
of Flight information services only and any message sent from Mogadishu FIC
shall not be construed as a clearance.
- When using CPDLC and ADS-C, VHF or HF voice frequencies will be
used as primary communication medium.
- To ensure correct synchronization of messages, controller/pilot
dialogue opened by voice must be closed by voice and dialogue open on CPDLC must
be closed by CPDLC except in emergency.
- Due to inherent integrity checks and a coded reference to any
proceeding related messages contained within CPDLC messages, essential traffic
information issued by CPDLC only the appropriate CPDLC response.
- To avoid potential ambiguity the use of multiple message elements
should be avoided, except when message elements are depending on each
other.
- If multiple essential traffic information requests are contained
in a single down-link message and the controller cannot approve all requests,
the uplink message “ UNABLE” will be sent as a response to the entire message. A
separate message containing a response to those request that can be complied
with, will be sent by the controlled.
- If any ambiguity exists as to the intent of a particular message,
clarification should be sought by voice
- Standard pre-formatted message elements will be used whenever
possible. Free text messages SHOULD ONLY be used when an appropriate
pre-formatted message element does not exist or to supplement the preformatted
message element.
- The use of free text messages shall be for provision of Flight
Information Services especially during the provision of Air Traffic Services.
All ATS provision messages like essential traffic information, climb and descend
requests, shall be made through free text.When CPDLC connection is established,
aircraft will be instructed to transfer from voice to CPDLC. The phraseology
used is: “transfer to Mogadishu FIC on datalink monitor…. (Frequency).
- CPDLC connections will be terminated at the FIR Boundary position
or as requested by the ATS Unit.
- The contact (unit/name) (frequency) message and the END SERVICE
message will be sent as separate messages. The END SERVICE message will be sent
as soon as possible after receipt of the “WILCO” response message to a contact
message.
- Pilots shall ensure that all uplink messages have been responded
to before termination or transfer of CPDLC to another data authority.
- When CPDLC fails and communication reverts to voice, all CPDLC
messages outstanding should be considered not delivered and effort made to
re-commence dialogue by voice (VHF or HF).
7.6
ADS-C Applications
- When a Controller or a Pilot recognizes a failure of a CPDLC
connection, they shall immediately establish voice communication on the
appropriate frequency. Voice communication shall continue to be used as a
primary means until a CPDLC connection has been re-established and the
controller has authorized the return to data link.
- In the event of CPDLC failure, the controller shall immediately
advice all data link connected aircraft of the failure by voice. Instructions
will continue to be issued by voice until the return of data link system. The
return of the system to an operational state will require a new AFN LOGON from
the affected aircraft.
- Planned shutdown of CPDLC ground system shall be notified by
publishing a NOTAM stating the shutdown period and details of voice
communication frequencies to be used.
- In case of ADS-C failure, the controller shall inform pilots of
the failure and CPDLC position reports will be used.
7.7
Emergency Procedures
- Pilots should notify ATC of emergency situations by the most
appropriate means (voice or CPDLC).
- If a CPDLC MAYDAY /PAN message is received, the controller will
immediately acknowledge receipt of the emergency by using the free text message
“ROGER MAYDAY/PAN”.
- Normal emergency procedures shall be followed. Controller may
also attempt to make voice contact with the pilot.
- For ADS-C aircraft, the ATS unit should base the provision of the
alerting service on any missed scheduled report.
- To indicate that it is in a state of emergency or to transmit
other urgent information, an aircraft equipped with ADS-C might operate the
emergency and/or urgency mode as follows:
- Emergency;
- Communication failure;
- Unlawful interference;
- Minimum fuel and; and/or Medical.
7.8 When an ADS-C emergency and/or urgency
report is received, the controller with responsibility for the flight must acknowledge
receipt of the information by the most appropriate means of communication.
7.9 Flight plan
notification Aircraft planning to utilize data link communication
must annotate their ICAO flight plan as follows:
- CPDLC Capability must be notified by inserting the alphanumeric
designator J4 in item 10 field 10a;
- ADS-C capability must be notified by inserting the alphanumeric
designator D1 in item 10 field 10b;
- Aircraft registration must be inserted in item 18 as the ground
system uses the information during the AFN LOGON