High altitude

The average elevation of Tibet is over 4,500 meters (14,800 feet), which means that the air density is much lower than at lower altitudes. At high altitudes, the air is thinner, which makes it more difficult for planes to fly, particularly in terms of maintaining their altitude and speed.

The reason for this difficulty lies in the way that planes generate lift. Planes generate lift through the use of their wings, which are designed to create an area of low pressure above the wing and high pressure below it. This pressure differential generates the lift that keeps the plane in the air. However, this process is dependent on the density of the air. At higher altitudes, the air is less dense, and there is less air available to generate lift. This means that planes need to fly faster to generate the same amount of lift, which can be challenging for the engines and the navigation systems of the plane.

Additionally, the low air density at high altitudes means that the air is less able to dissipate heat, which can cause issues with the engine cooling systems. In extreme cases, the engines may even fail, which could be catastrophic for the plane and its passengers.