from USCG district 5 Local Notice to Mariners: NATIONAL TRANSPORTATION SAFETY BOARD ON GPS The National Transportation Safety Board (NTSB) has issued an Urgent Class I Recommendation to the U.S. Coast Guard following the grounding of a cruise ship. The recommendation included a request to advise mariners of the possible safety problems associated with Global Positioning System (GPS) receivers which automatically revert to dead reckoning (DR) tracking when satellite fixes are not received for a period of time. In the case prompting this advisory, it is believed a cruise ship ran aground due to an antenna failure resulting in the loss of satellite signals. This reverted the GPS to use positions based on DR tracking as input to the autopilot. Alarms indicating the receiver was in the DR mode were not heard nor detected visually, which led to a course error of 14 nautical miles. This casualty was preventable by personnel. Vessel operators are advised of this circumstance and are urged to review the design of their bridge systems to identify potential system and operational failure modes that might result in undetected changes to the autopilot function and develop modifications as required. Additionally, bridge officers are reminded not to rely on any single aid to navigation, but to use all navigation resources at hand. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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