Fatigue and the IMSAFE Checklist
Why pilot fitness matters as much as aircraft fitness, and a simple self-assessment before every flight.
A legal, airworthy aircraft is only half of a safe flight — the pilot must be fit too. Fatigue in particular degrades judgement, reaction time and attention much like alcohol, and it's easy to underestimate.
IMSAFE
Run this personal pre-flight checklist on yourself:
- I — Illness: Am I sick? Even a cold affects the sinuses and ears.
- M — Medication: Am I taking anything that could impair me? Many over-the-counter drugs are disqualifying.
- S — Stress: Work, family or financial pressure that will distract me?
- A — Alcohol: "Eight hours bottle to throttle" is the legal minimum (and below 0.04%); the effects last longer.
- F — Fatigue: Am I rested? Acute and cumulative fatigue both impair performance.
- E — Emotion / Eating: Am I emotionally ready, hydrated and fed?
Fatigue specifically
Fatigue narrows attention, slows decisions and makes you more likely to accept risk. The dangerous part is that a tired pilot is poor at judging their own impairment. The only real fix is rest — not caffeine. If IMSAFE turns up a problem, the safe answer is often to delay or cancel. The flight will wait.
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*Reference and training only — not for navigation. Always consult the current AIM, FAR/AIM, your aircraft’s POH/AFM and a certificated flight instructor.*