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Transponder pressure relief system failure

Whilst reviewing its test and repair procedures for transponders, a member has reported that a serious flaw was discovered in the pressure relief mechanism in two out of three Kongsberg transponders tested. Such transponders are in common use across marine operations world-wide and it is possible that some could exhibit the same fault whereby internal pressure build-up would not be able to be vented automatically.

It appeared that the pressure relief mechanism was locked in place and would not operate, possibly due to an assembly fault by the manufacturer.

Pending detailed instructions from the manufacturer, the contractor instructed its personnel not to disassemble any such transponders.

Kongsberg has been exploring the matter, relating to the RPT model transponder (which went out of production in 2002) and has now issued a technical bulletin on the subject, a copy of which is attached.

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