"If the weather is fine,

This is really difficult to answer. I learned to stand on the ground before. When the weather is clear and there are no obstacles, we can see 12 miles away, and then the horizon.

But when we fly, the weather is different because there is no reference object, because the refraction of air humidity makes us see different distances.

One of our buddies said that when he flew to Xi 'an, he saw the Qinling Mountains more than 200 kilometers away. I didn't see it that far, but at night, I saw the beacon lights at the airport 50 nautical miles away, and the visibility was excellent. But the lights are particularly bright. But if the reference object is very small, I may not see it for several kilometers.

If it is really good enough, it can see farther than 200 kilometers in a rational state.

But in general, the visibility is greater than 10sm, which means it is very good weather. So if you want to see far, you can only rely on luck. ..

By the way, haha, I was also curious just now. I looked around and saw an academic emperor say that in an absolutely ideal state, if you count the refraction of 30 thousand inches, you can see about 500 kilometers from the ground. ..