SUB-COMMITTEE ON
RADIOCOMMUNICATIONS AND SEARCH
AND RESCUE
4th session
Agenda item 6
COMSAR 4/6/2
14 April 1999
Original: ENGLISH
SATELLITE SERVICES (INMARSAT AND COSPAS-SARSAT)
Shore-to-ship communications during distress
Note by the United States
SUMMARY
Executive summary: The Sub-Committee published COMSAR/Circ. 13 as an interim means for Rescue Coordination Centers to communicate during a SAR operation with a ship whose ship earth station is already in use, but those means should not be considered permanent solutions. This document proposes improved solutions be considered as a long-term solution.
Action to be taken: Paragraph 3
Related documents: COMSAR/Circ.13 COMSAR 2/3/16
Introduction
1 At COMSAR 2, Norway noted the difficulty RCC Stavanger experienced in communicating with the Co-ordinator Surface Search during the Achille Lauro SAR operation, due to the line being busy as a result of the large numbers of calls from the media (COMSAR 2/3/16). At COMSAR 3, the Sub-Committee prepared COMSAR/Circ. 13 addressing the issue, but also agreed this circular be kept under review.
2 COMSAR/Circ. 13 notes that "If the SES is being called from an RCC via another CES from which the ongoing call has been established, then there is no option but wait until the call has cleared and the SES is idle to set up a priority." Noting that most ships would likely carry an Inmarsat-C, it suggests the option of RCC's sending "a Distress priority message in the shore-to-ship direction asking the ship to clear their Inmarsat voice terminal and contact the RCC immediately."
Discussion
3 While the procedure described by COMSAR/Circ. 13 is currently the best solution available, it is an imperfect one, and should not be a permanent one. Options currently available from wireline telephone carriers in managing the same problem during an emergency could be models for SES communications. For example, in an emergency a wireline telephone operator is able to interrupt and join an on-going conversation, and a "call waiting" tone can be transmitted to the telephone user indicating a new call is being made. In the cases of an SES, a shore-to-ship distress priority call could have a unique "call waiting" tone indicating the priority.
