What is air traffic control?

There are two types of delays before a plane takes off, one is caused by the airline, and the other is caused by air traffic control. Airlines' reasons include aircraft turnover, crew lateness, aircraft maintenance, etc. In short, the aircraft or crew did not arrive at the airport on time/enter the take-off preparation state. Air traffic control means that the aircraft meets all other take-off conditions, but the tower does not let it go. There are many reasons for non-release. weather. This is divided into three types: departure airport weather, destination weather, and most importantly, route weather. Bad weather (heavy rain, fog, lightning, strong winds, etc.) is not suitable for takeoff, landing and flying. One cannot fly due to bad weather. Airways are congested. All China’s airspace is managed by the Air Force. The Air Force gives 20% of it to civil aviation (which can be taken back at any time). In this 20% space, some routes are set. There are requirements for the spacing between aircraft on the route, front, rear, left and right. If there are too many planes on the same route, new planes cannot be allowed to fly in, otherwise there will be safety problems. military activities. As mentioned above, 20% of the airspace is given by the Air Force to civil aviation. If the air force is to be used, civil aviation must give way. A typical example is military exercises. Then a no-fly zone will be drawn nearby (usually 300-500 kilometers), all aircraft will be detoured, and the routes will need to be adjusted. Runway problem. The airport runway may be temporarily closed due to maintenance or conditions on the runway (such as a large number of birds). With fewer runways, takeoff and landing capabilities are reduced, but flights are scheduled according to normal conditions, so extra queuing time is required. There is not much you can do if air traffic control occurs (except that Li Gang is on the plane), you can only wait patiently in line. The queue is based on closing the cabin door (this means that the aircraft has the conditions to push out, taxi and then take off). Planes with their doors closed can queue up at the tower, but those whose doors are not closed cannot queue up. So when airlines encounter air traffic control, they don’t really want to keep passengers in the cabin. Because if you are not locked in the cabin, you will never be able to take off. Of course, not all delays are caused by air traffic control, nor does it mean that air traffic control is caused by air traffic control.