13800m

13800m refers to a specific altitude, measured in meters above sea level. This height is significant within the context of aviation and atmospheric science. Commercial airliners typically cruise at altitudes between 10,000m and 12,000m, placing 13,800m well above standard flight paths for passenger aircraft. At such an altitude, the air is considerably thinner, meaning there is less oxygen and atmospheric pressure. This makes sustained human presence without specialized equipment impossible.

The Karman line, often considered the boundary of space, is located at 100 kilometers (100,000m) above sea level. Therefore, 13,800m is well within Earth's atmosphere. Specialized aircraft, such as reconnaissance planes or high-altitude research aircraft, are capable of reaching and operating at altitudes like 13,800m. For example, the U-2 reconnaissance aircraft has been documented flying at altitudes exceeding 21,000m, far surpassing 13,800m. Scientific balloons can also ascend to and operate at these altitudes for atmospheric research. The challenges of operating at 13,800m include the need for pressurized cabins, specialized oxygen systems, and materials that can withstand extreme cold and low pressure.