A DPO is on watch during a sensitive DP3 drilling operation. DGNSS Unit 1 is showing a stable, clean position trace — exactly as expected in the calm conditions. DGNSS Unit 2 has been showing minor fluctuations. The DPO, reassured by Unit 1, pays less attention to Unit 2 and stops cross-checking the Fanbeam against both DGNSS units. Which human factor is operating, and what is its specific DP risk?

A. The risk is minimal because DGNSS Unit 1 and the Fanbeam are independently powered, removing the common cause failure risk

B. The DPO is correct to focus on the cleanest reference — a stable DGNSS trace is the best available data and should be trusted

C. Confirmation bias — seeking and weighting information that confirms the expected picture (stable position, calm conditions) while discounting or ignoring information that doesn't fit (fluctuating Unit 2). The specific DP risk is that Unit 2's fluctuations may be early signals of a developing fault, a common cause problem, or an actual position excursion that Unit 1 is not yet showing. Stopping cross-checks removes the comparison mechanism that position reference redundancy is built on

D. This is normal reference management — experienced DPOs learn which references are most reliable on their vessel and use them accordingly

A. The concern is only valid if a client representative is present on the bridge during the exceedance

B. The lead DPO is correct — if the vessel has held position every time, the limit was probably set too conservatively and can be informally adjusted upward

C. Repeated limit exceedance without incident is the definition of normalisation of deviance — each incident-free violation makes the next seem safer, eroding the original safety margin without any formal review. The ASOG limit exists because someone calculated the risk; overriding it verbally on the basis that "nothing happened" removes the agreed safety envelope without authorisation

D. The ASOG yellow limit is a guideline, not a hard limit — the DPO has discretion to continue past yellow if conditions feel manageable

A. The DPO should use quiet periods for paperwork — productive use of downtime is more valuable than passive monitoring

B. Boredom is an acceptable state during calm DP watches — the automated system manages everything and the DPO is there as a backup

C. Extended uneventful periods create the highest complacency risk in DP watchkeeping: the DPO's vigilance degrades precisely because nothing has demanded it. When a fault develops — a reference dropout, a thruster fluctuation, a slow position drift — the response time increases because the DPO's attention is elsewhere. Long periods of routine are when the first small signals of developing problems are most likely to be missed

D. The risk is limited to DP Class 1 vessels — DP2 and DP3 systems have sufficient automated monitoring to compensate for reduced DPO attention during quiet periods