Specific Sizes And Colors
Besides that, the cables that zigzag across these areas must be marked with visibility marker balls. Otherwise, as planes descend, their pilots may not see the lines ahead of them. The FAA guidelines also specify why the balls should be available in specific sizes and colors.
Specific Sizes And Colors
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Extra Large Spheres
The spheres that you see above lakes, rivers, and canyons are extra-large, as you may have guessed. In fact, the FAA requires that they be at least 36 inches wide. However, for power lines less than 50 feet in height, the smaller markers – 20-inch balls – are deemed adequate. The scaled-down versions can also be found at the end of airport runways.
Extra Large Spheres