Decision Simulator

Ali Ka — Challenging the Pilot, River Thames

Ali Ka
Chemical tanker, 129.5m · River Thames, Canvey Island, England · 25 October 2022
Source: MAIB 6/2024

3Decision Points 0Possible Outcomes Avg. Play Time

The Situation

You are the master of the chemical tanker Ali Ka, departing Oikos 1 jetty on the River Thames in the dark, pre-dawn hours. No tug is available for the move — booked elsewhere — and the pilot is visibly concerned about the falling tide, pushing to get underway before the window closes. You've already raised the lack of a tug once; the pilot reassured you and the plan continues.

The Lesson

Raising a concern once and accepting reassurance isn't the same as resolving it. PACE exists precisely because the interpersonal cost of a first probe is low — the real test is whether you're willing to escalate to Challenge or Emergency when reassurance doesn't actually address the risk.

Human Element

Pilot fatigue was the probable initiating factor, but the MAIB's own Human Factors lens on this case names the real contributing failure as an authority gradient: the bridge team did not challenge the pilot's developing approach plan. The master raised concerns about the tug — real, on the record — but never escalated past reassurance-seeking into a formal PACE-style challenge once the manoeuvre was already underway and deteriorating.

Try the First Decision

0400: no tug has been found, the tide is falling faster than planned, and the pilot is now visibly hurrying preparations. You've already asked once about the tug and been reassured. What do you do?

A. PROBE again, directly: "Given no tug and the tide still dropping, are we still comfortable with this plan?" — and wait for a real answer, not just reassurance
B. Accept the pilot's earlier reassurance and let the departure proceed as planned

This is a preview — the full scenario branches from here based on what you choose, with real consequences and a debrief at the end.

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