Question 1

During a routine watch, the DPO notices the DGNSS and Fanbeam are starting to show a small but growing divergence — well within the ASOG green limit. Rather than waiting for an alarm, the DPO quietly increases monitoring frequency, briefs the relieving watch on the trend, and the divergence resolves on its own an hour later as a satellite geometry issue clears. How should this event be treated?

Accepted Answer

As a positive resilience event worth recording and discussing — the DPO anticipated a developing issue before it triggered any alarm or limit, monitored it actively, and communicated it forward; this proactive behaviour is exactly what should be reinforced and is genuine safety performance, not "nothing happened" This is a textbook Safety-II "averted issue" — the DPO's anticipation and monitoring prevented a developing situation from ever reaching a limit. A Safety-I lens would record nothing because no rule was broken; a Safety-II lens recognises and reinforces the proactive behaviour that made the non-event possible, which is exactly the kind of practice an assessor wants to see a candidate articulate.

Question 2

What is the fundamental difference in focus between a Safety-I approach and a Safety-II approach to DP operations?

Accepted Answer

Safety-I focuses on identifying and eliminating causes of things going wrong, defining safety as the absence of incidents; Safety-II focuses on understanding how things usually go right despite variability, defining safety as the presence of the capacity to adapt and succeed under varying conditions Safety-I (the traditional model) reacts to failure — find the cause, eliminate it, count incidents as the measure of safety. Safety-II (Hollnagel) recognises that most days nothing goes wrong because people and systems continuously adapt to everyday variability — and argues that understanding and supporting that adaptive capacity is at least as valuable as counting failures.

Question 3

What is meant by the distinction between "work-as-imagined" and "work-as-done" in a DP context, and why does it matter?

Accepted Answer

"Work-as-imagined" is what procedures, checklists, and management assume happens; "work-as-done" is what actually happens on watch, including the informal adaptations crew make to handle real conditions — gaps between the two are where unrecognised risk and unrecognised good practice both hide Procedures are written for an idealised, generalised scenario. Real watches involve constant small adaptations — workarounds for known quirks, informal checks, local knowledge — that the procedure never captured. Recognising this gap is central to Safety-II: the adaptations are often exactly what is keeping things safe, not a deviation to be punished.