Why are planes often delayed because of flow control? What is flow control?

Flow control refers to maintaining safe air traffic flow by limiting the number of aircraft entering an air traffic control node per unit time.

That is, planes line up one after another on the tarmac or in the air, waiting for instructions to take off or descend and land. Just like when you check in, for flight safety, you need to queue up for security check one by one.

Generally speaking, "flow control" means routing flow control. Why is there flow control? At present, the number of daily flights in China is about 13000. Some people may say that the sky is high and the clouds are light, and these flights are nothing. In fact, although the sky is vast, the routes are limited, and the routes open to civil aviation are even more limited.

In order to ensure flight safety, the air traffic control department controls the flow of aircraft in the air route or airport with large flight flow to avoid dangerous approach or air collision between aircraft. Or because the airport is busy, the runway is limited, the planes queue to take off or the destination airport is busy, control the originating airport.

Extended data:

Flight delays due to air traffic control:

First of all, civil aviation routes are not open to me, but in limited airspace. At the same time, civil aircraft in the air, like cars on the ground, will be restricted and influenced by many factors.

Civil aircraft take off, land and fly in limited space, limited time and limited conditions. At present, the air traffic in some busy airports is overloaded, and planes often slide on the ground or even wait for a long time to take off.

References:

Official Website of Chengdu Shuangliu International Airport-Flow Control