How many kilometers is the flight from Xining to Guangzhou?

Under normal circumstances, the flight distance from Xining to Guangzhou is about 2200KM.

Although the data in this field has been published in recent years, it has not reached a casual level, and it is still relatively conservative in China. However, since it is data that can be made public, it is still possible to simply popularize science.

1 Importance of air route

It may be different from what most people think. The seemingly empty blue sky is not how you want to fly. Any aircraft (except toy planes played by children) has all kinds of strict rules in the sky that are beyond ordinary people's imagination. It can be said that the route in the sky is far more complicated than the road on the ground. The biggest difference from everyone's imagination is that it is definitely not a straight line. Although we all know that the straight line between two points is the closest, for various reasons, the plane completed its flight according to the strictly stipulated route and waypoint. Otherwise, everyone will fly in a straight line or according to their own wishes, and the sky will be completely out of order. Therefore, in the air, aircraft should walk on the route in strict accordance with the requirements of airspace controllers.

2 Definition of air route

For a better understanding, we can regard each route as an invisible expressway. The distance after taking off from the airport runway can be regarded as the ramp of expressway, that is, the process of accelerating the integration into expressway, also known as the departure route. When the speed, altitude and heading all reach the relevant specified values, then the plane will officially enter expressway. For example, an airplane needs different "expressway" to get from point A to point B. And every turning place is a waypoint, and we can regard it as an overpass. Different expressway connect here, and then go to the next expressway through this overpass. Finally, after a series of actions, we arrive near the destination, slow down, adjust the course and reduce the altitude in turn, leave expressway, enter the ramp of the destination airport, that is, the approach line, and finally reach a destination.

3 Xining-Guangzhou route

Although the linear distance from Xining Airport to Guangzhou Airport is only about 1820KM. But in fact, the actual route from Xining to Guangzhou is about 2200KM. According to the setting of the route along the way, we can see that Xining did not fly directly to the southeast after taking off and entering the route, because there was no route over Xining in this direction. Then you need to fly east and south according to the existing route, reaching the airspace near Lanzhou, which is equivalent to reaching the first "overpass", then adjusting the course, entering the next "expressway" to fly to Guyuan, and so on. Finally, after several constant adjustments, it arrived in Guangzhou. (The straight line in the picture below is the theoretical straight line distance between the two airports, and the winding is the normal flight route of civil aviation. Of course, this artificial map measurement is not very accurate, mainly for better understanding. The actual flight distance may be shorter, probably less than 2200KM. )

Why can the route only be approximate, but not accurate?

First of all, because the actual distance of each flight may be different, such as the approach/departure route (mainly affected by the wind direction, climate and flight flow of the local airport), the detour caused by weather/flow factors in the route, and so on.

Secondly, there is another thing that will affect the flight distance to the greatest extent, and that is the rotation of the earth. As we all know, our earth rotates from west to east, with the North Pole counterclockwise and the South Pole clockwise. So for flying, if it flies from west to east, it is equivalent to the same direction as the earth's rotation. In other words, the plane is chasing the earth, so although there is no obvious difference as a ground reference system, the actual flight distance in the air has become longer. On the other hand, if you fly from east to west, it is equivalent to the opposite direction of the earth's rotation. Although the distance from the ground will remain relatively unchanged, the distance of flying in the air will actually become shorter. This is why airspeed and ground speed have different concepts in flight. Therefore, especially in the east or west direction, there will be obvious differences in flight time between departure and return, because the length of the route is relatively "changing". Of course, for the northwest-southeast route from Xining to Guangzhou, which is not too far away, the influence of the earth's rotation on the route distance can be basically ignored. The east-west routes across time zones, such as Urumqi-Beijing, will have a great impact on the distance and flight time.