Tibet has always been regarded as a "no-go area in the air", because of the thin air, complex climate and other reasons, even if the way to Tibet can reduce the flight distance, most of the flights will choose to go around, do not dare to easily Tibet into the route.
But in fact, a check of Tibetan airports can reveal that there are civil airports in many areas of Tibet such as Gongga and Linzhi. Among them, the highest altitude Ali Kunsha airport, but also just built in the altitude of 4274 meters, the aircraft thought to fly more than four thousand meters above sea level is also no problem at all, but why most flights did not choose the Tibet route?
Aircraft navigation must take into account the altitude of the area through which the route passes. The average altitude of civil airliners is between 6,000-12,600 meters, while the average altitude of the Tibetan region has exceeded 4,000 meters, excluding the highest 8,848 meters of Mount Everest, the height of the 7-8,000-meter peaks are also as many as several dozen.
In Tibet, there is also the historically famous "Hump Route". It was an air transport route opened by the United States to transport supplies from India to China during World War II, during which pilots had to fly over the Himalayas.
Until the end of World War II, the U.S. Army lost more than 1,500 aircraft and nearly 3,000 outstanding pilots, a loss rate of more than 80%, while Chinese airlines also lost 168 pilots, a loss rate of more than 50%. Therefore, this route was also known as the "death route".
Even in today's more advanced flight technology, civil airliners wanting to fly safely in the Tibetan alpine group must fly to an altitude of more than 10,000 meters. Although many aircraft can reach this height, but it does not mean that there is no risk of collision at 10,000 meters.
In 1992, a Pakistani flight with 167 passengers on board was passing through the Himalayas when it crashed into a mountain range because it was flying too low, killing all the people on board.
In the Tibetan region, high mountains gather and the terrain is complex. If the crew cannot judge and avoid the high mountains in time, an accident can easily happen, so even if there is only a one in ten million chance of impact, the crew should never take the risk.
Complex turbulence at high altitude in Tibet
The terrain structure of the surface, the air flow also has a great impact on the complex terrain, the air flow is extremely unstable, it is easy to trigger turbulence. To use an analogy, if the aircraft is a moving car, then turbulence is the mud puddles on the road, the larger the mud puddles, the more dangerous the car driving, but turbulence can be much more dangerous than the obstacles on the road.
How dangerous is it for an aircraft to encounter turbulence?
In May 2022, a civilian airliner flying from Mumbai to Durgapur, West Bengal, was less than 200 km from its destination airport when it encountered sudden weather extremes. The aircraft entered turbulence and began to lurch severely. The crew immediately instructed passengers to return to their seats and fasten their seat belts to reduce casualties from the lurch.
However, under the strong turbulence, the plane's airspeed suddenly dropped by about 100 knots and then rose again, causing the passengers and crew inside to lose gravity and take off into the air before being heavily thrown back into position. Oxygen masks were automatically ejected and cabin luggage fell during the violent bumps, injuring many passengers. In just a few minutes, the cabin became a mess, and at least 14 passengers and three crew members were injured in the incident.
Fortunately, the plane eventually landed at the destination airport without incident, while in 1996, a British airliner that encountered turbulence was tragically involved in a plane crash that killed 124 people.
Flight accidents caused by turbulence occur from time to time, and modern techniques have been researched that can effectively avoid strong turbulence, but turbulence is still difficult to predict because the atmospheric structure has become very complex due to the many mountain ranges in Tibet and the large drop between peaks.
Moreover, turbulence has an interfering effect on light, sound and electromagnetic waves, and stronger turbulence, which can directly block the aircraft from the ground. If only a short period of turbulence will not have much effect, and soon resume normal flight, but if the airflow is difficult to calm down for a long time, then the aircraft will face a greater risk of accidents.
Polar flights are prone to fuel freezing
Aircraft do not fly as high as possible. Flying at too high an altitude can cause the aircraft to freeze in fuel.
Aircraft flight is the need for fuel, as the flight altitude rises, the temperature and air pressure will gradually drop, once encountered minus 47 ℃, at this time, the aircraft fuel will be like water, the phenomenon of icing.
In 2008, a flight from Beijing to London, England, crashed directly onto the airport runway while landing at an altitude that was almost touching the ground. The cause of this tragedy was that the plane was crossing over Siberia when the low temperature of -20℃ caused the fuel system to freeze, plus the pilot's mishandling, the engine suddenly lost power and there was no way to give normal power output, so the plane was forced to land on its belly.
The low temperature of minus 20 ℃, it has happened the fuel system freezing, and the Tibetan plateau year-round snow, glaciers are widespread, the average temperature throughout the year has been as low as minus 40 ℃. As we mentioned earlier, if an aircraft is to fly over Tibet, which has an average altitude of 4,000 meters, then the flight altitude must be higher than 10,000 meters, and when the aircraft flies at a higher altitude, the temperature will also decrease. This increases the likelihood of fuel freezing in aircraft flying over the Tibetan plateau.
In order to alleviate the fuel icing problem, pilots generally choose to lower their altitude, but if they choose to lower their altitude, they increase the risk of crashing into the mountain, which completely puts the pilots in a dilemma, and whichever one they choose, there is an extremely high risk.
In the event of an accidental aircraft failure, it will be difficult to save yourself
On the one hand, although the Tibetan land is wide, but there are few alternate airports, if the plane needs to emergency landing, the probability is that even the airport is not found.
Moreover, considering the high altitude and thin air in Tibet, the power performance of the aircraft will be reduced accordingly, and the runway distance for aircraft take-off and landing should be longer than the normal airport runway. At present, the runway of Tibet airport, except for Linzhi Milin Airport which is 3000 meters, the runway of the rest of the airport is above 4000 meters.
If a sudden accident, the aircraft can not find the nearest airport to land, then the only choice is to land on flat terrain or water, but in Tibet there are no such conditions, even outside the airport to find a long enough to land the runway is not possible.
On the other hand, if an aircraft encounters an accident, it needs to save itself by adjusting its flight altitude, changing its flight path and other measures. In the high and mixed mountain ranges of Tibet, either lowering its altitude or temporarily changing its course is a great risk to take.
The importance of Tibet flights
Of course, the distribution of airports in Tibet is by no means ornamental, with the development of tourism, many people will also choose to travel to Tibet, by air is the fastest way, 2022 Lhasa Gongga Airport flights and gradually increased to nearly 50 more, it can be seen, there are still some airlines in the case of ensuring safety, will choose to set up flights to Tibet.
Moreover, the Tibetan aircraft also serve as air transport maintenance. In addition to tourism, Tibet also transports melons, fruits and vegetables, yak meat, matsutake mushrooms and other products outward, and air transportation can not only ensure the freshness of food, but also transport the products directly to more distant cities such as Beijing and Xiamen. It can be seen that Tibet airline also exists an important value and is one of the important links to help Tibet's economy take off at a high speed.
At present, modern technology is fully capable of flying over Tibet, and airlines try to avoid flying over Tibet not because Tibet cannot be flown, but to ensure the safety of passengers and crew and to minimize safety risks.