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.
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding [email protected] to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.
IMCA’s store terms and conditions (https://www.imca-int.com/legal-notices/terms/) apply to all downloads from IMCA’s website, including this document.
IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.