When preparing for a night flight, what should an sUAS pilot be aware of after assembling and conducting a preflight using a bright flashlight or work light?
AOnce adapted to darkness, a person's eyes are relatively immune to bright lights.
BIt takes approximately 30 minutes for a person's eyes to fully adapt to darkness.✓
CThe person should use a flashlight equipped with LED lights to facilitate their night vision.
Why →The human eye requires approximately 30 minutes to fully dark-adapt after bright light exposure. During dark adaptation, rhodopsin (a light-sensitive pigment in rod cells) regenerates. Exposure to bright white light resets this process.
The trap →Once adapted to darkness, eyes are EXTREMELY sensitive to bright lights, which completely resets adaptation. LED flashlights are just as disruptive as incandescent. The LED type doesn't help. Red-light flashlights are the aviation standard.
Field note →Use a red-filtered headlamp for all pre-flight checks at night. Red light has minimal effect on rhodopsin regeneration. Avoid looking at car headlights, phone screens, or any white light in the 30 minutes before a critical night operation.
SOURCE → FAA Aeronautical Information Manual, FAA UAG Sample Question 43CHECKED JUL 16ACS V.A.K8MED