Why is the current plane still affected by fog, rain and snow?

There are certain conditions for airplane flight. In addition to all the functions of the aircraft itself, there are objective environmental conditions. The specific specifications are stipulated by ICAO.

One of them is that you can't fly in fog, rain and snow. The reason for this is the following：

1, the above weather will affect the visibility of pilots. Although navigation is the main thing, the visual observation of pilots is also very important. For example, there are birds or balloons in front, and the pilot should avoid them, but neither birds nor balloons can be detected by radar.

2. The above weather conditions will cause the aircraft surface to freeze. It takes no more than half an hour for the plane to fly from the ground to an altitude of 8 thousand meters or even 10 thousand meters, and some even take more than ten minutes. In foggy or rainy days, the air contains a lot of condensed water. When the plane takes off from the airport, the condensed water will adhere to the surface of the plane. When the plane is afraid of rising to the sky, because the air temperature in the sky is very low, below 0 degrees, water will freeze and attach to the surface of the plane, and the ice will freeze after absorbing the moisture in the atmosphere, and the ice layer will become thicker and thicker. The reason why an airplane can fly is that its wing shape should keep the original design shape. After icing, the shape of the wing will change to a certain extent, and there is no fixed law to follow this change, so after icing, the control of the aircraft will fail. The plane may lose lift. Although the aircraft has its own deicing or anti-icing system, the system only works in unexpected icing weather conditions, that is, its working capacity is limited and it is impossible to keep it on all the time.

When there is fog, rain and snow on the ground, it is not necessarily the same weather at high altitude. The temperature in the sky is extremely low, and there may be ice particles or ice cubes on it. Planes fly very fast, especially engines. Once these hard ice cubes are inhaled, it may cause the engine to stall and the fuselage to crack. Affect flight safety.

Maybe there are other factors. That's all I can think of.