Question 1

Under what circumstances is it appropriate to inhibit or suppress a DP alarm?

Accepted Answer

Inhibition is appropriate when a known, documented condition is temporarily causing a nuisance alarm that cannot be corrected immediately (e.g. a reference system offline for planned maintenance) — it must be recorded in the DP log, reviewed regularly, and re-enabled as soon as the condition is resolved Inhibiting a nuisance alarm from a known, documented fault is operationally legitimate when properly managed — but only with a clear rationale, a log entry, and active monitoring that the inhibited condition does not change. Uninhibited inhibit practices (suppressing an alarm and forgetting about it) create exactly the conditions where a critical state change goes undetected.

Question 2

How are alarms typically categorised in a DP alarm management system, and what does each category indicate?

Accepted Answer

High-priority (Category 1): requires immediate action — position-critical failure or imminent risk; Medium-priority (Category 2): requires prompt attention — reference degraded, thruster fault; Low-priority (Category 3): advisory — condition monitor, early warning. Each category drives a different urgency of response DP systems typically implement a three-tier alarm hierarchy: Category 1 (or equivalent) requires immediate DPO response to prevent position loss; Category 2 alerts the DPO to degraded conditions; Category 3 provides advisory information. The hierarchy allows the DPO to prioritise attention correctly under stress.

Question 3

What is alarm flooding and why is it particularly dangerous in a DP context?

Accepted Answer

Alarm flooding occurs when multiple alarms activate simultaneously or in rapid succession, overwhelming the operator's ability to diagnose the root cause — in DP, this can mask the critical alarm that actually predicts position loss, causing the DPO to miss the most important signal among the noise Multiple investigations into DP incidents and marine accidents have cited alarm flooding as a human factors contributor — when every alarm demands attention simultaneously, cognitive overload leads to important alarms being missed, suppressed without being read, or buried under lower-priority warnings. IMO MSC-FAL.1/Circ.3 specifically addresses alarm management design to reduce flooding.