FAA Airline Transport Pilot (ATM)Human Factors and CRMMedium
A pilot flying an overnight cargo flight has been awake since 6:00 a.m. and is now attempting to land at 4:00 a.m. after 22 hours of continuous wakefulness. The primary human factors concern in this scenario is that performance degradation from this level of fatigue is comparable to a blood alcohol concentration of approximately:
- A0.16 percent
- B0.10 percent
- C0.05 percent
- D0.02 percent
Show answer & explanationAnswer & explanation
Correct answer: B. 0.10 percent
Research on sleep deprivation has found that being awake for approximately 17-19 hours produces performance impairment equivalent to a BAC of 0.05%, and 24 hours awake is roughly equivalent to 0.10% BAC. At 22 hours awake, the pilot's impairment is approaching the 0.10% level, exceeding the 0.08% legal driving limit in most states.
Why the other options are wrong
- A. 0.16% would represent an extreme level of impairment beyond what 22 hours of wakefulness typically produces.
- C. 0.05% corresponds to about 17-19 hours awake, less than the 22 hours in this scenario.
- D. 0.02% would correspond to only a few hours of extended wakefulness, far less impairment than 22 hours.
Fatigue and Wakefulness Impairment
Extended wakefulness produces cognitive and motor impairment comparable to alcohol intoxication, a key concept in fatigue risk management for flight crews.
- 17 hours awake ≈ 0.05% BAC impairment
- 24 hours awake ≈ 0.10% BAC impairment
- Circadian low points (0200-0600) worsen fatigue effects
- Fatigue impairs judgment, reaction time, and situational awareness similarly to alcohol
Memory trick: 17 hours awake = one beer buzz (0.05%); 24 hours = legally drunk (0.10%)