【正文】 and ? ? Atsea maintenance (ASM). 2022 April GMDSS Services – Lecture 1 92/93 s 。 and ? ? Atsea maintenance (ASM). 2022 April GMDSS Services – Lecture 1 91/93 On ships trading in areas A3 and A4, this availability shall be ensured by using a bination of at least two of the following methods: ? ? Duplication of equipment (DOE)。 and ? ? Atsea maintenance (ASM). 2022 April GMDSS Services – Lecture 1 90/93 Ships trading in areas Al and A2, shall ensure this availability by using at least one of the following methods: ? ? Duplication of equipment (DOE)。 ? b) for stations on board ships which sail within the range of VHF coast stations, taking into account the provisions of SOLAS: a holder of a firstor second – class radio electronic certificate or a general operator’s certificate (GOC) or a restricted operator’s certificate (ROC)(2) 2022 April GMDSS Services – Lecture 1 88/93 Means of Ensuring Availability of Ship Station Equipment ? The SOLAS Convention requires that each country shall ensure that the radio equipment is maintained to provide the availability of those nine functions detailed above. 2022 April GMDSS Services – Lecture 1 89/93 3 maintenance methods: ? ? Duplication of equipment (DOE)。 ? The GMDSS provides facilities for all types of mercial and personal munications. GMDSS radio operators need to know how to make telephone and telex calls to shipping agents, port authorities, the public telephone work etc. through mercial telemunication works. 2022 April GMDSS Services – Lecture 1 82/93 transmission and reception of bridgetobridge munications。 RescueUnit that will then have the means to locate the distressed raft or vessel. 2022 April GMDSS Services – Lecture 1 77/93 2022 April GMDSS Services – Lecture 1 78/93 transmission and reception of maritime safety information ( MSI )。 ? “ On scene munications” are short to medium range munications (generally via VHF or MF) carried out during the course of a search and rescue operation (between ship in distress and SAR units or between SAR units). For this purpose, ships must be able to municate with aircraft, as well as with other ships, using the dedicated GMDSS frequencies for voice and NBDP distress munications. 2022 April GMDSS Services – Lecture 1 75/93 transmission and reception of signals for locating。 ? A ship in distress can alert other ships in the vicinity by sending a DSC distress alert on VHF and MF, simultaneously if desired, and follow it up with a distress (MAYDAY) voice message on Channel 16 or 2182 kHz. Note that HF DSC is for longrange work and is intended primarily for alerting the shorebased authorities, especially if there are no ships in the vicinity. 2022 April GMDSS Services – Lecture 1 68/93 transmission and reception of search and rescue coordinatingmunications。 2022 April GMDSS Services – Lecture 1 65/93 ? Details for each individual ship are to be found on its Safety Radio Certificate. On a Sea Area A1 ship, for example ( which always remains within DSC range of a shore VHF station) the primary means would be the VHF DSC, and the secondary means could be an EPIRB. In the case of a Sea Area A4 ship, the primary means would have to be HF DSC and the secondary means a 406 MHz EPIRB. 2022 April GMDSS Services – Lecture 1 66/93 reception of shoretoship distress alerts。 North and South, but excludes A1 and/or A2 designated areas 2022 April GMDSS Services – Lecture 1 58/93 2022 April GMDSS Services – Lecture 1 59/93 Sea Area A4 ? An area outside sea areas A1, A2 and A3. This is essentially the polar regions, north and south of about 70186。 Indian Ocean Region (IOR)。 Search and Rescue Radar Transponder