Two notes ride with the model. First, diagnosis deserves its double-check: a faulty diagnosis solves the wrong problem perfectly, so confirmation from the other crew member (or a deliberate, calm re-check when alone) belongs at the very first stage. Second, the model has a fast path: SOPs and rule-based behaviour reduce the amount of decision-making crews must do at all — the procedure is a decision made in advance, in an office, with all the time in the world.
Risk, commitment and time
Risk splits into two categories the exam asks by name. External (objective) risk is the risk of an accident in the current situation if nothing is changed. Internal (subjective) risk is the crew's own inability to implement a solution, through lack of know-how or lack of time to apply it — and it increases linearly as the deadline approaches. A risk factor is anything that increases the likelihood of an accident, and a proper assessment weighs both the amount of risk and its probability.
Commitment is the degree of commitment to a chosen solution: the point of no return, past which the decision spends itself whether right or wrong. Its relationship with time pressure is the strategy heart of the lesson: contrary to instinct, a crew can usually make time in the air: convert the approach into a go-around, take a hold, delay the take-off, reduce speed, divert. And when time genuinely cannot be made (an emergency at take-off or landing, close to the ground), the only effective solution is a decision prepared in advance: thorough flight preparation and briefings before every high-risk phase, accepting the residual hazard of an error of commission: a prepared response committed to the wrong event. Commercial considerations deserve suspicion here, because fuel and schedule quietly self-impose time limits that safety never asked for.
Bias: the tilted scales
Humans are poor probability assessors, and the syllabus wants the tilt described. Rare but pleasant outcomes are overestimated (the entire lottery industry rests on it); well-published negative events are overestimated too (fatal accidents), while unglamorous ones are underestimated (the airprox, the slow disease). Framing is the deepest tilt: offered two losses, people choose the risky loss over the certain one — the certain loss of turning back (late, embarrassed) against the gamble of pressing on, and press-on-itis has filled accident reports with the results. Framed as two gains, the bias reverses toward the sure thing, which offers the counter: reframe the choice (the certainty of keeping everyone alive versus the possibility of arriving on time) and the scales tilt toward wisdom. Add confirmation bias (countered by deliberately hunting for falsifying information) and saliency bias (the loud, bright, recent cue dominates while the vital quiet one is missed) and the catalogue the previous lessons kept meeting is complete.
The remaining error sources in an individual's decision mechanism: overconfidence, which breeds complacency and the deterioration effect (often blamed for the accident peak among pilots of 1,000 to 3,000 hours, past the humility of inexperience and short of wisdom), fatigue and overload, and denial — the refusal to confront the real situation, wearing its six familiar coats: procrastination, rationalization, hope and desires, refusal to admit, status and reputation, refusal to review. The mechanism's limits complete the picture: attention (funnelled under stress, so inputs are curtailed), stress itself, and lack of experience, which slows diagnosis because no pattern library exists yet to match the cues against.
High workload, short time
Procedures that demand much in little time (the go-around above all) expose attention's two failure directions at once. Dispersion scatters attention across the simultaneous demands (power, pitch, configuration, radio, navigation) until none is done well; channelised attention funnels onto a single compelling cue while the rest of the procedure starves. Both are stress's signature on the single-channel processor, and the counter is the one the whole module has been building: a briefed, rehearsed, rule-based response, prepared when time was cheap, so that execution needs the channel less exactly when the channel has least to give.
The group in the loop
A multi-crew decision is usually better than the average individual's decision (consultation is a genuine asset), but it is seldom better than the ablest member's, and the group adds distortions of its own. Conformity presses the doubter to agree with the room; status makes the senior voice persuasive regardless of correctness. The one the syllabus names is the risky shift: a group's decision tends to be riskier than the average of its members' private judgements, for two reasons: responsibility diffuses (blame shared is blame diluted), and high-risk individuals tend to dominate, persuasive and leadership-shaped, tilting the room their way. A crew culture that prizes boldness compounds it. The wider machinery of groups, leadership and authority gradients is the next module's subject; here the lesson is narrower: know that the room can tilt you, and audit a group consensus as sceptically as a private hunch.