What is the required physiological night rest duration?

• A. 8 hours
• B. 12 hours
• C. 6 hours
• D. 10 hours

Answer: (D)

The idea behind this question is how long a pilot should be given to sleep at night to recover from fatigue and be ready for the next duty. The recommended physiological night rest duration is 10 hours. This longer rest window helps ensure you have enough time not just to fall asleep, but to complete several full sleep cycles and achieve high-quality restorative sleep. It also provides a comfortable buffer for potential delays, awakenings, or pre-sleep routines, so you wake up rested rather than sleep-deprived.

Eight hours can be enough for many people, but in aviation fatigue planning, a 10-hour window is favored to account for irregular schedules and circadian challenges, increasing the likelihood of meeting actual sleep needs. Six hours is generally insufficient for full recovery, and twelve hours tends to be more time than necessary, tying up schedule time without added benefit.