An unassociated failure of one part of a gyro system affected the DP system
- DP Event
- Published on 27 February 2018
- Generated on 9 May 2025
- DPE 01/18
- 2 minute read
Undesired event
The systems connected to the DP system need to be fully understood to avoid failures in one connected part affecting the whole DP system.
Comments
A new Gyro was installed as a replacement but failed to start with first attempt.
Further investigation revealed that the ‘Gyro 2 remote control unit’ located on the forward bridge had a fault, failure of it caused Gyro 2 to shut down. When the ‘Gyro 2 remote control unit’ was disconnected the new Gyro was switched on with no further problems.
After a stabilisation period the Gyro was tested, found operational and the signal to DP reinstated. DP operations were resumed.
In conclusion, the original Gyro 2 was, and remains, healthy.
Considerations
- It can be assumed that good operational activity planning took place and the ASOG indicated a yellow alert to be activated with the loss of one gyro.
- The logic of systems connected to the DP system need to be fully understood so that a failure in one part of a connected system does not affect the DP system.
- With the availability of so many position reference systems, it may be better to use two DGNSS, and keep the other two DGNSS as monitoring.
- It is unclear what the Gyro 2 remote control unit is required for, but it appears to have introduced an additional failure mode of the gyro and should have been identified in the DP FMEA.
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The case studies and observations above have been compiled from information received by IMCA. All vessel, client, and operational data has been removed from the narrative to ensure anonymity. Case studies are not intended as guidance on the safe conduct of operations, but rather to assist vessel managers, DP operators, and technical crew.
IMCA makes every effort to ensure both the accuracy and reliability of the information, but it is not liable for any guidance and/or recommendation and/or statement herein contained.
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