On the surface, the rule is deceptively simple: if the runway can’t be seen, abandon the approach. But it is a rule that doesn’t account for the spectre of temptation. Cloud is a visual siren, beckoning pilots to come a little closer, promising them the comforting view of their destination if they surrender their sense of caution.

Taking the path of least resistance is a human trait. For crews to resist such a lure – at the point of greatest vulnerability, when journey’s end is tantalisingly ­within reach – takes extraordinary discipline.

That it snares experienced and inexperienced pilots flying aircraft from presidential transports to flag-carriers to budget operators, proves that no-one is completely immune to the risk – especially if the source of ­psychological ­pressure is external as well as internal. The decision-altitude rule is maddening in its absolute unambiguity. On the scale of automation ­feasibility, ­discerning whether a runway is visible or not is a task far better suited to the human pilot than a machine. The irony is that, having made the correct determination, the human is more likely to fail to act on it.

Solving this problem requires a mind-shift. Executing a missed approach at the decision height, and even diverting, needs to become a more attractive option than persisting with a bad approach. As the situation stands, the possibility of avoiding a serious accident simply isn’t attractive enough.

Source: Flight International