Why do passenger planes fly at an altitude of 10,000 meters?

In short - they do not fly at this altitude. At least not always. Even though we very often hear the captain say, “We have reached our cruising altitude of 10,000 meters,” before the seatbelt icon goes off.

So what exactly determines the altitude at which a passenger plane flies? Three pilots of passenger airliners tried to answer this question.

There is an ideal height.

In principle, the higher the plane flies, the thinner the air. This is good and bad at the same time. Good, because drag is reduced and the aircraft needs less fuel. But, on the other hand, oxygen for burning fuel also becomes less, which affects the power. Increasing the height requires a longer lift and higher fuel consumption. Therefore, the pilot wants to find a middle ground, where the plane will fly as fast as possible, but spend the least amount of fuel.

The ideal altitude for all aircraft is different.

Determining the ideal altitude is based on the characteristics of the aircraft, its weight and atmospheric conditions at the time of flight. For most liners, the ideal height is between 9,000 and 12,000 meters.

... And is determined by a number of factors.

These include flight direction, turbulence and flight duration. For example, there is a rule that commercial airliners heading to the northeast, east and southeast fly at odd altitudes (9,000 m, 11,000 m, etc.), while moving in other directions rise to even height.

Airline controllers calculate the ideal altitude for each flight.

Air traffic controllers operate at their headquarters. They control the planning and progress of flights. They track where the planes are, their condition, and also assign each their own route.

There are roads in the sky.

They are called reactive routes, and dispatcher services use them to separate planes at a certain distance or height, regulate their movement and control the flow of traffic.