← All explained questions · Supplemental · XI — Night Operations
How long does it typically take for the eyes to fully dark-adapt for night flight?
Choices
✓ Approximately 30 minutes.correct
Full dark adaptation takes about 30 minutes. Even a brief exposure to bright white light (cockpit lights, flashlight, lightning) can destroy adaptation and require restarting the 30-minute clock. This is why pilots use red or low-intensity white light in the cockpit at night.
About 5 minutes.
5 minutes is far too short — only initial pupil dilation has occurred.
Less than 1 minute.
Dark adaptation is not instantaneous.
Up to 2 hours.
Adaptation completes around 30 min, not 2 hours.
Why
Full dark adaptation takes about 30 minutes. Even a brief exposure to bright white light (cockpit lights, flashlight, lightning) can destroy adaptation and require restarting the 30-minute clock. This is why pilots use red or low-intensity white light in the cockpit at night.
FAA source: PHAK Ch 17, AIM 8-1-6; PHAK Chapter 17 — Aeromedical Factors; AIM 8-1-6 Vision in Flightbrowse the reference library →
Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.