Why do Jet Airplanes Fly at High Altitudes?


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High Altitudes and the Atmospheric Conditions

Most of the weather phenomenon occurs in the troposphere, the atmospheric layer closest to the surface of the earth. The average height of the troposphere is taken as 36000ft, however it does vary depending on the region from which it is being measured (polar, equatorial) and temperature of the atmosphere. Water vapor is heavily concentrated within this layer in the form of clouds, precipitation, steam, etc.

An Airbus A380 cruising at/about 40,000ft! Photo Credit: Angus MacRae

Flight above the troposphere helps avoid a considerable amount of weather phenomenon (thunderstorms and heavy rain clouds). Similarly, an aircraft in flight at high altitudes would have a higher chance of avoiding turbulence, icing conditions (due to lower water vapor concentration at high altitudes) and wind shear.

Hence flight at higher altitudes is relatively more efficient than low altitude flying and more safe with regards to weather phenomenon. Operators compromise the lack of oxygen and pressurization requirements at high altitudes for more efficient flights. Instead, the air is pressurized through a fail safe system for comfortable flight at higher flight altitudes, as per the FAA regulations.


Aviation Theory Centre. Meteorology and Navigation. (1999).

Aviation Theory Centre. Aeroplane General Knowledge and Aerodynamics. (2004).

Oxford Aviation Services. Joint Aviation Authorities Airline Transport Pilot’s License Theoretical Knowledge Manual. (2001). Accessed January 30, 2012.

NASA Glenn Research Center. Density Effects on Aerodynamic Forces. Accessed January 30, 2012.

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