One of the most important aspects of a safe flight operation is the requirement for crew members to carefully monitor the aircraft's flight path and systems, as well as actively cross-check each other's actions. Humans are not good at monitoring constant situations and, therefore, it is easy to fall behind the aircraft. This is especially true when no deviations are expected to occur, as in the case when monitoring automated systems. This can induce a feeling of automation complacency (too much reliance on the machine) and lead you not to check things as often as you should (hypovigilance).

Hypovigilance is a lack of attention to detail, it is akin to a microsleep which can occur at any time during the flight, especially during periods of monotony, reduction of workload, during simple and repetitive tasks, low lightning, high temperature and constant and monotonous noise.