Which statement about fatigue is consistent with the description?

• A. It increases alertness.
• B. It causes permanent cognitive decline after one incident.
• C. It is a transient state that cannot be reversed.
• D. It is a physiological state that reduces alertness and performance.

Answer: (D)

Fatigue is a physiological state that reduces alertness and performance. It stems from extended wakefulness, inadequate or disrupted sleep, and demanding workloads, and it impairs vigilance, decision-making, and reaction time. This aligns with the statement you’re evaluating because fatigue lowers how alert you are and how well you perform tasks, which is the core effect pilots need to manage. Importantly, fatigue is reversible with adequate rest and recovery, not a permanent change from a single incident. It isn’t something that would increase alertness, nor does it cause permanent cognitive decline after one event, and it isn’t described as an irreversible condition.