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GMDSS Handbook
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Annex - 9-4
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Mob-87
ARTICLE N 39
Mob-87
Operational Procedures for Distress and Safety Communications in the Global Maritime Distress and Safety System (GMDSS)
Section I. General
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N 3106 Mob-87 з 1. Distress and safety communications rely on the use of terrestrial MF, HF and VHF radiocommunications and communications using satellite techniques.
N 3107 Mob-87 з 2. (1) The distress alert (see No. N 3112) shall be sent through a satellite either with absolute priority in general communication channels or on exclusive distress and safety frequencies or, alternatively, on the distress and safety frequencies in the MF, HF and VHF bands using digital selective calling.
N 3108 Mob-87 (2) The distress alert (see No. N 3112) shall be sent only on the authority of the person responsible for the ship, aircraft or other vehicle carrying the mobile station or the mobile earth station.
N 3109 Mob-87 з 3. All stations which receive a distress alert transmitted by digital selective calling shall immediately cease any transmission capable of interfering with distress traffic and shall continue watch until the call has been acknowledged.
N 3110 Mob-87 з 4. Digital selective calling shall be in accordance with the relevant CCIR Recommendations.
Mob-87
Section II. Distress Alerting
N 3111 Mob-87 A. General
N 3112 Mob-87 з 5. (1) The transmission of a distress alert indicates that a mobile unit1 or person2 is in distress and requires immediate assistance. The distress alert is a digital selective call using a distress call format3 in bands used for terrestrial radiocommunication or a distress message format, in which case it is relayed through space stations.
N 3113 Mob-87 (2) The distress alert shall provide4 the identification of the station in distress and its position.
N 3112.1 Mob-87 1) Mobile unit: A ship, aircraft or other vehicle.
N 3112.2 Mob-87 2) In this Article, where the case is of a person in distress, the application of the procedures may require adaptation to meet the needs of the particular circumstances.
N 3112.3 Mob-87 3) The format of distress calls and distress messages shall be in accordance with the relevant CCIR Recommendations.
N 3113.1 Mob-87 4) The distress alert may also contain information regarding the nature of the distress, the type of assistance required, the course and speed of the mobile unit, the time that this information was recorded and any other information which might facilitate rescue.
N 3114 Mob-87 B. Transmission of a Distress Alert
Mob-87 B1. Transmission of a Distress Alert by a Ship Station or a Ship Earth Station
N 3115 Mob-87 з 6. Ship-to-shore distress alerts are used to alert Rescue Co-ordination Centres via coast stations or coast earth stations that a ship is in distress. These alerts are based on the use of transmissions via satellites (from a ship earth station or a satellite EPIRB) and terrestrial services (from ship stations and EPIRBs).
N 3116 Mob-87 з 7. Ship-to-ship distress alerts are used to alert other ships in the vicinity of the ship in distress and are based on the use of digital selective calling in the VHF and MF bands. Additionally, the HF band may be used.
Mob-87 B2. Transmission of a Shore-to-Ship Distress Alert Relay
N 3117 Mob-87 з 8. (1) A station or a Rescue Co-ordination Centre which receives a distress alert shall initiate the transmission of a shore- to-ship distress alert relay addressed, as appropriate, to all ships, to a selected group of ships or to a specific ship by satellite and/ or terrestrial means.
N 3118 Mob-87 (2) The distress alert relay shall contain the identification of the mobile unit in distress, its position and all other information which might facilitate rescue.
Mob-87 B3. Transmission of a Distress Alert by a Station Not Itself in Distress
N 3119 Mob-87 з 9. A station in the mobile or mobile-satellite service which learns that a mobile unit is in distress shall initiate and transmit a distress alert in any of the following cases:
N 3120 Mob-87 a) when the mobile unit in distress is not itself in a position to transmit the distress alert ;
N 3121 Mob-87 b) when the master or person responsible for the mobile unit not in distress or the person responsible for the land station considers that further help is necessary.
N 3122 Mob-87 з 10. A station transmitting a distress alert relay in accordance with Nos. N 3119, N 3120, N 3121 and N 3134 shall indicate that it is not itself in distress.
N 3123 Mob-87 C. Receipt and Acknowledgement of Distress Alerts
Mob-87 C1. Procedure for Acknowledgement of Receipt of Distress Alerts
N 3124 Mob-87 з 11. Acknowledgement by digital selective calling of receipt of a distress alert in the terrestrial services shall be in accordance with relevant CCIR Recommendations;
N 3125 Mob-87 з 12. Acknowledgement through a satellite of receipt of a distress alert from a ship earth station shall be sent immediately (see No. N 3129).
N 3126 Mob-87 з 13. (1) Acknowledgement by radiotelephony of receipt of a distress alert from a ship station or a ship earth station shall be given in the following form:
- the distress signal MAYDAY;
- the call sign or other identification of the station sending the distress message, spoken three times ;
- the words THIS IS (or DE spoken as DELTA ECHO in case of language difficulties);
- the call sign or other identification of the station acknowledging receipt, spoken three times;
- the word RECEIVED (or RRR spoken as ROMEO ROMEO ROMEO in case of language difficulties);
- the distress signal MAYDAY.
N 3127 Mob-87 (2) The acknowledgement by direct-printing telegraphy of receipt of a distress alert from a ship station shall be given in the following form:
- the distress signal MAYDAY;
- the call sign or other identification of the station sending the distress alert ;
- the word DE;
- the call sign or other identification of the station acknowledging receipt of the distress alert ;
- the signal RRR;
- the distress signal MAYDAY .
N 3128 Mob-87 з 14. The acknowledgement by direct-printing telegraphy of receipt of a distress alert from a ship earth station shall be given by the coast earth station receiving the distress alert, by retransmitting the ship station identity of the ship transmitting the distress alert.
Mob-87 C2. Receipt and Acknowledgement of Receipt by a Coast Station, a Coast Earth Station or a Rescue Coordination Centre
N 3129 Mob-87 з 15. Coast stations and appropriate coast earth stations in receipt of distress alerts shall ensure that they are routed as soon as possible to a Rescue Co-ordination Centre. Receipt of a distress alert is to be acknowledged as soon as possible by a coast station, or by a Rescue Co-ordination Centre via a coast station or an appropriate coast earth station.
N 3130 Mob-87 з 16. A coast station using digital selective calling to acknowledge a distress call shall transmit the acknowledgement on the distress calling frequency on which the call was received and should address it to all ships. The acknowledgement shall include the identification of the ship whose distress call is being acknowledged.
Mob-87 C3. Receipt and Acknowledgement of Receipt by a Ship Station or Ship Earth Station
N 3131 Mob-87 з 17. (1) Ship or ship earth stations in receipt of a distress alert shall, as soon as possible, inform the master or person responsible for the ship of the contents of the distress alert.
N 3132 Mob-87 (2) In areas where reliable communications with one or more coast stations are practicable, ship stations in receipt of a distress alert should defer acknowledgement for a short interval so that receipt may be acknowledged by a coast station.
N 3133 Mob-87 з 18. (1) Ship stations operating in areas where reliable communications with a coast station are not practicable which receive a distress alert from a ship station which is, beyond doubt, in their vicinity, shall, as soon as possible and if appropriately equipped, acknowledge receipt and inform a Rescue Co-ordination Centre through a coast station or coast earth station (see No. N 3121).
N 3134 Mob-87 (2) However, a ship station receiving an HF distress alert shall not acknowledge it but shall observe the provisions of Nos. N 3139 to N 3141, and shall, if the alert is not acknowledged by a coast station within 3 minutes, relay the distress alert.
N 3135 Mob-87 з 19. A ship station acknowledging receipt of a distress alert in accordance with No. N 3132 or No. N 3133 should:
N 3136 Mob-87 a) in the first instance, acknowledge receipt of the alert by using radiotelephony on the distress and safety traffic frequency in the band used for the alert:
N 3137 Mob-87 b) if acknowledgement by radiotelephony of the distress alert received on the MF or VHF distress alerting frequency is unsuccessful, acknowledge receipt of the distress alert by responding with a digital selective call on the appropriate frequency.
N 3138 Mob-87 з 20. A ship station in receipt of a shore-to-ship distress alert (see No. N 3117) should establish communication as directed and render such assistance as required and appropriate.
N 3139 Mob-87 D. Preparations for Handling of Distress Traffic
N 3140 Mob-87 з 21. On receipt of a distress alert transmitted by use of digital selective calling techniques, ship stations and coast stations shall set watch on the radiotelephone distress and safety traffic frequency associated with the distress and safety calling frequency on which the distress alert was received.
N 3141 Mob-87 з 22. Coast stations and ship stations with narrow-band direct-printing equipment shall set watch on the narrow-band direct-printing frequency associated with the distress alert signal if it indicates that narrow-band direct-printing is to be used for subsequent distress communications. If practicable, they should additionally set watch on the radiotelephone frequency associated with the distress alert frequency.
Mob-87
Section III. Distress Traffic
N 3142 Mob-87 A. General and Search and Rescue Co-ordinating Communications
N 3143 Mob-87 з 23. Distress traffic consists of all messages relating to the immediate assistance required by the ship in distress, including search and rescue communications and on-scene communications. The distress traffic shall as far as possible be on the frequencies contained in Article N 38.
N 3144 Mob-87 з 24. (1) The distress signal consists of the word MAYDAY , pronounced in radiotelephony as the French expression "m'aider".
N 3145 Mob-87 (2) For distress traffic by radiotelephony, when establishing communications, calls shall be prefixed by the distress signal MAYDAY.
N 3146 Mob-87 з 25. (1) Error correction techniques in accordance with relevant CCIR Recommendations shall be used for distress traffic by direct-printing telegraphy. All messages shall be preceded by at least one carriage return, a line feed signal, a letter shift signal and the distress signal MAYDAY.
N 3147 Mob-87 (2) Distress communications by direct-printing telegraphy should normally be established by the ship in distress and should be in the broadcast (forward error correction) mode. The ARQ mode may subsequently be used when it is advantageous to do so.
N 3148 Mob-87 з 26. (1) The Rescue Co-ordination Centre responsible for con- trolling a search and rescue operation shall also co-ordinate the distress traffic relating to the incident or may appoint another station to do so.
N 3149 Mob-87 (2) The Rescue Co-ordination Centre co-ordinating distress traffic, the unit co-ordinating search and rescue operations1 or the coast station involved may impose silence on stations which interfere with that traffic. This instruction shall be addressed to all stations or to one station only, according to circumstances. In either case, the following shall be used :
N 3149.1 Mob-87 1) In accordance with the International Convention on Mari- time Search and Rescue, 1979, this is the on-scene commander (OSC) or the co-ordinator surface search (CSS).
N 3150 Mob-87 a) in radiotelephony, the signal SEELONCE MAYDAY , pronounced as the French expression "silence m'aider" ;
N 3151 Mob-87 b) in narrow-band direct-printing telegraphy normally using forward-error correcting mode, the signal SILENCE MAYDAY .However, the ARQ mode may be used when it is advantageous to do so
N 3152 Mob-87 з 27. Until they receive the message indicating that normal working may be resumed (see No. N 3154), all stations which are aware of the distress traffic, and which are not taking part in it,. and which are not in distress, are forbidden to transmit on the frequencies in which the distress traffic is taking place.
N 3153 Mob-87 з 28. A station of the mobile service which, while following distress traffic, is able to continue its normal service, may do so when the distress traffic is well established and on condition that it observes the provisions of No. N 3152 and that it does not interfere with distress traffic.
N 3154 Mob-87 з 29. When distress traffic has ceased on frequencies which have been used for distress traffic, the Rescue Co-ordination Centre controlling a search and rescue operation shall initiate a message for transmission on these frequencies indicating that distress traffic has finished.
N 3155 Mob-87 з 30. (1) In radiotelephony, the message referred to In No. N 3154 consists of:
- the distress signal MAYDAY ;
- the call "Hello all stations" or CQ (spoken as CHARLIE QUEBEC) spoken three times;
- the words THIS IS (or DE spoken as DELTA ECHO in the case of language difficulties);
- the call sign or other identification of the station sending the message ;
- the time of handing in of the message ;
- the name and call sign of the mobile station which was in distress ;
- the words SEELONCE FEENEE pronounced as the French words "silence fini".
N 3156 Mob-87 (2) In direct-printing telegraphy, the message referred to in No. N 3154 consists of:
- the distress signal MAYDAY;
- the call CQ ;
- the word DE :
- the call sign or other identification of the station sending the message ;
- the time of handing in of the message ;
- the name and call sign of the mobile station which was in distress; and
- the words SILENCE FINI.
N 3157 Mob-87 B. On-scene communications
N 3158 Mob-87 з 31. (1) On-scene communications are those between the mobile unit in distress and assisting mobile units, and between the mobile units and the unit co-ordinating search and rescue operations1.
N 3159 Mob-87 (2) Control of on-scene communications is the responsibility of the unit co-ordinating search and rescue operations1. Simplex communications shall be used so that all on-scene mobile stations may share relevant information concerning the distress incident. If direct-printing telegraphy is used, it shall be in the forward error-correcting mode.
N 3160 Mob-87 з 32. (1) The preferred frequencies in radiotelephony for on- scene communications are 156.8 MHz and 2 182 kHz. The frequency 2 174.5 kHz may also be used for ship-to-ship on-scene communications using narrow-band direct-printing telegraphy in the forward error correcting mode.
N 3161 Mob-87 (2) In addition to 156.8 MHz and 2 182 kHz, the frequencies 3023 kHz, 4125 kHz, 5680 kHz, 123.1 MHz and 156.3 MHz may be used for ship-to-aircraft on-scene communications.
N 3162 Mob-87 з 33. The selection or designation of on-scene frequencies is the responsibility of the unit co-ordinating search and rescue operations1. Normally, once an on-scene frequency is established. a continuous aural or teleprinter watch is maintained by all participating on-scene mobile units on the selected frequency.
N 3158.1 Mob-87
N 3159.1 Mob-87
N 3162.1 Mob-87		 1) In accordance with the International Convention on Maritime Search and Rescue, 1979, this is the on-scene commander (OSC) or the co-ordinator surface search (CSS).
N 3163 Mob-87 C. Locating and Homing Signals
N 3164 Mob-87 з 34. (1) Locating signals are radio transmissions intended to facilitate the finding of a mobile unit in distress or the location of survivors. These signals include those transmitted by searching units, and those transmitted by the mobile unit in distress, by survival craft, by float-free EPIRBs, by satellite EPIRBs and by search and rescue radar transponders to assist the searching units.
N 3165 Mob-87 (2) Homing signals are those locating signals which are transmitted by mobile units in distress, or by survival craft, for the purpose of providing searching units with a signal that can be used to determine the bearing to the transmitting stations.
N 3166 Mob-87 (3) Locating signals may be transmitted in the following frequency bands : 117.975 -136 MHz; 156- 174 MHz; 406- 406.1 MHz: and 9 200 -9 500 MHz.
N 3167 Mob-87 (4) Locating signals shall be in accordance with the relevant CCIR Recommendations.
N 3168 to N 3195 NOT allocated.
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Radio Officer й 2002 Edition
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