Wiley Post was an aviation pioneer. He was the first pilot to fly solo around the world, invented the pressurized suit in order to fly at higher altitudes (paving the way for NASA to create the space suit), and is widely credited with discovering the jet stream.

At the age of 26, before he started flying, Wiley Post lost his left eye (and as a result, his depth perception) in an industrial accident. Using the money from the resulting settlement, he bought his first aircraft and began his aviation career. Without this settlement, he never would have been able to buy his first plane. And so, if he had never lost his depth perception, he never would have become a pilot.

So if he can fly just fine without his depth perception, why in the name of Pete is it such a big deal to the FAA that I can't see green?