To protect your eyesight at night, which of the following should you use?

Using a red aviation flashlight at night is optimal for protecting your eyesight because red light is less disruptive to your night vision. The human eye is more sensitive to blue and white light, which can cause temporary blindness or discomfort when transitioning from darkness to light. This adaptation process can take significant time, impairing visibility and performance. A red light helps to preserve your night vision while still providing enough illumination for necessary tasks and navigation, allowing you to see without compromising your ability to detect other lights and objects in the dark.

In contrast, a bright white flashlight can severely hinder night vision and cause the eyes to adjust slowly back to darkness. A regular reading light, being similar to white light, presents the same issues as a bright flashlight. Choosing no light at all may be appropriate in certain situations, but it can also lead to greater risks of accidents during critical phases of flight, as you may not be able to see important instruments or visual cues around you. Therefore, using a red aviation flashlight strikes a balance between visibility and maintaining adequate night vision.