NOPSEMA identifies more loss-of-position incidents

Article published in the Regulator | Issue 2: 2017 

Since 2016, NOPSEMA has been raising concerns with industry about dynamic positioning (DP) systems and the susceptibility of its ‘auto position’ mode to be inadvertently deactivated. This concern originated from an incident in Australian Commonwealth waters where a vessel unintentionally drifted off-location. Although no-one was injured, divers working on the seabed nearby were put at risk.

The investigation into the incident found that the vessel had lost its position because the DP operator placed a notepad on the DP system's console, which inadvertently pressed down on the ‘surge’ button, deactivating the ‘auto position’ mode. NOPSEMA concluded that the incident was a result of human error made possible by a weakness in the design of the DP system. NOPSEMA shared the lessons learned in Safety alert 62, available under the 2016 heading at

NOPSEMA identified two similar incidents in the United States and United Kingdom, also attributed to human error and the design of the DP system. The similarity between these incidents prompted NOPSEMA to publicise the problem in the first issue of the Regulator (available and review historical DP incident data from an industry association. NOPSEMA identified a further 14 incidents resulting in a loss of position, with the first recorded in 2002. Every incident was caused by the inadvertent deactivation of the DP system’s auto position mode. In five cases, it was the placement of a log book or clipboard that inadvertently deactivated the system.

Over the life of a facility, an operator’s risk management processes should identify opportunities to improve existing control measures or implement additional control measures to ensure risks are continually being reduced to a level that is as low as reasonably practicable (ALARP). For example, at a recent facility inspection, NOPSEMA found the operator had added a Perspex guard to the DP console to reduce the likelihood of inadvertent deactivation. NOPSEMA believes this is a useful interim control measure pending manufacturer improvements, and encourages other operators to do the same.

NOPSEMA identifies more loss of position incidents

NOPSEMA would like to remind facility operators of their duty to take all reasonably practicable steps to ensure that any plant, equipment, materials and substances at their facility are safe and without risk to the health and safety of the offshore workforce. Facility operators should ensure the safety management system described in their facility’s safety case provides for the continual and systematic identification of hazards, assessment of risks, and reduction of risks to a level that is ALARP.

We also remind manufacturers that they also have a duty to take all reasonably practicable steps to ensure that the plant is designed and constructed so that, when properly used, it is without risk to the health and safety of the offshore workforce. Manufacturers must carry out the research, testing, and examination necessary to discover and eliminate, or minimise, any risk to health and safety that may arise from the use of the plant.