Despite the successful deployment of new direction-finding equipment, there are still some problems with the 406-MHz EPIRB—most notably, false alarms.
- Since 2004, more than 96% of 406-MHz EPIRB activations in the United States were from false or unknown causes.
- Since 2004, 45% of 406-MHz EPIRB activations were from either unregistered EPIRBs or from EPIRBs with obsolete registration information, which delays Coast Guard response.
- The Coast Guard spends 20 to 50 aircraft hours monthly (costing $200,000 to $700,000 dollars) on sorties for false EPIRB activations.
The design of some 406-MHz EPIRBs contributes to a high number of false activations. For example, one model is manufactured so that it can be installed backwards. If installed incorrectly, the model activates upon getting wet. Also, some EPIRBs are manufactured with loose bracket straps that allow moisture to unintentionally activate the EPIRB.
While some poorly designed EPIRBs are slowly being phased out of service, the remaining 406-MHz EPIRBs in the field (over 220,000 U.S.-registered) will continue to waste Coast Guard time and effort until they are properly installed and registered with current contact information.
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Full article is available at http://www.uscg.mil/proceedings/winter2009.
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