Which device produces a bright patch visible from the air?

• A. Strobe light
• B. Dye marker use
• C. Signal mirror use
• D. Whistle purpose

Answer: (B)

When a search aircraft needs to spot someone on the water, a bright, high-contrast visual cue on the surface is most effective. A dye marker is designed to create a colored patch on the water that stands out from the blue of the sea, making it easy to see from above in daylight. This directly satisfies the goal of a “bright patch visible from the air.”

Strobe lights can be seen from the air, especially at night or in poor visibility, but they rely on power and lighting conditions, and they don’t create a lasting patch on the water’s surface. A signal mirror reflects sunlight toward an observer, which requires the sun, correct angle, and direct line of sight, and it doesn’t produce a surface patch. A whistle is audible but provides no visual cue that would help an aircraft locate you.

So the dye marker’s colored patch on the water is the most reliable visual signal for air search.