The Reason Why Most Planes Don't Fly Over Tibet

You might think that airplanes have the freedom to fly wherever they please, but there are certain limitations. Planes don't fly over Antarctica, for example. But that's a barren landscape without any major cities or tourist destinations, so it makes sense that pilots would rarely need to cross the largest continent in the world. Tibet, on the other hand, has a population of 3.6 million and shares one of the most popular tourist attractions in the world with Nepal: Mount Everest. But this attraction is also one of the reasons pilots tend to avoid flying over the 474,287 square mile area.

Tibet sits on a plateau with an especially treacherous terrain full of mountain ranges, earning the country the fitting nickname of the "roof of the world." There are 1,121 named mountains in the region, including Everest, with an average elevation of 15,000 feet. Everest itself stands at 29,032 feet. Sure, the typical service ceiling for commercial airplanes of 35,000 to 45,000 feet means that they could just fly over the peaks, but it's not as simple as that.

Those mountains are the main culprits for turbulence, making any flight over the region a rocky one. Turbulence occurs when the airflow is disrupted, which both man-made structures and naturally occurring landmarks like mountains can cause. Pressure differentials also disrupt the airflow, so flying higher in less-than-ideal weather can also create an issue.

Passenger planes have their cabins pressurized to make the environment more suitable for their passengers, something the little hole in airplane windows helps with. The aircraft's cabin pressurizes so the passengers feel like they're only at 8,000 feet, even when they're really at 35,000 feet or higher. If planes weren't pressurized, it would be difficult to breathe at higher altitudes due to the thinner air. Without pressurization, the passengers would lose consciousness from hypoxia. If the cabin suddenly depressurizes, the standard procedure is to decrease the plane's altitude to 10,000 feet, where the oxygen is breathable again.

A plane spontaneously depressurizing is admittedly rare, but it does happen. For example, Japan Airlines Flight 123 experienced an explosive decompression at 24,000 feet in 1985. This resulted in a rupture to the plane's fuselage and the loss of its Auxiliary Power Unit (APU), rudder, and vertical stabilizer. Since the average height of the mountains in Tibet is around 15,000 feet, it may not be possible to descend to 10,000 feet if this happens.

That incident was caused by poorly executed repairs, something that could be exacerbated by turbulence. Tibet is a sparsely populated country with few airports, and its rocky terrain doesn't make for the safest of places to land without an airfield. So, unless an aircraft is landing at one of the airports within Tibet's borders, pilots will avoid its treacherous airspace.