Loss of DP position caused by incorrect gyro heading
An incident has been reported to IMCA in which a DP Class 2 shuttle tanker lost its position during a DP offtake operation due to sudden and simultaneous loss of all position reference systems. Investigation disclosed that loss of DP position reference systems was directly caused by incorrect gyro heading, corrupting all offset calculations in the DP model.
Root cause of incorrect gyro heading was found to be erroneous GPS signals to all gyros over a short period of time.
A corrective action in the form of more stringent criteria for acceptance of position reference systems into the DP has already been established.
Furthermore the gyro manufacturer is about to upgrade the software to include rejection of erroneous GPS latitude/speed compensation data.
Safety Event
Published: 21 May 2008
Download: 
IMCA SF 09/08
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