FAA Ground School Practice Test

Why is it important to avoid bright lights before a nighttime flight?

1. To improve focus on navigation aids

2. To allow the eyes to adjust for night vision

3. To prevent fatigue during the flight

4. To enhance the clarity of charts

The correct answer is: To allow the eyes to adjust for night vision

Avoiding bright lights before a nighttime flight is important because it allows the eyes to adjust for optimal night vision. Human eyes require time to adapt to low-light conditions, a process that can take 20 to 30 minutes. When exposed to bright lights, such as those from screens or other sources, this adaptation is disrupted, making it more difficult to see in the dark. Proper night vision is crucial for detecting other aircraft, understanding the terrain, and interpreting navigational aids under low-light conditions. While improving focus on navigation aids, preventing fatigue, and enhancing clarity of charts are all considerations in nighttime flying, they do not directly relate to the physiological adaptation of the eyes to darkness, which is fundamental for safe nighttime navigation. Optimal night vision is a critical factor that enhances overall situational awareness and safety during nighttime operations.