FAA Commercial Pilot Airplane (CAX)Human Factors and ADMMedium

A commercial pilot completed a 13-hour duty day with back-to-back charter flights after getting only 5 hours of sleep the previous night, but reports feeling fully recovered after a normal night's rest. This scenario best describes which type of fatigue?

  1. ASkill fatigue
  2. BAcute fatigue
  3. CCircadian fatigue
  4. DChronic fatigue
Show answer & explanation

Correct answer: B. Acute fatigue

Acute fatigue is short-term tiredness from a single demanding day or reduced sleep that is resolved with a normal period of rest, unlike chronic fatigue, which accumulates over multiple days and is not relieved by one night's sleep.

Why the other options are wrong

  • A. 'Skill fatigue' is not a recognized FAA fatigue category in this context.
  • C. Circadian fatigue relates to disruption of the body's internal clock, such as time-zone or shift changes, not a single sleep-restricted day.
  • D. Chronic fatigue results from repeated sleep debt over multiple days and is not fully resolved by a single rest period.

Acute Fatigue

Normal, everyday tiredness resulting from a busy or sleep-restricted day that is relieved by a sufficient period of sleep or rest.

  • Resolves with one good night's sleep
  • Contrast with chronic fatigue, which accumulates over days and is not easily relieved
  • Impairs judgment, reaction time, and vigilance similarly to alcohol impairment

Memory trick: One bad night, one good sleep fixes acute fatigue.

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