In the sky, planes fly at altitudes different from each other. And for a lot of different reasons too, like the weight of the plane, the distance it has to travel or the weather.
If you’ve been on a plane before, you may have been surprised not to hear the captain always announce the samecruising. This is because the altitude at which an airplane flies depends on many factors. And first of all, the type of plane you boarded. Thus, jet airliners generally fly higher than turboprop airliners. On average between 30,000 and 40,000 feet, or between 9,200 and 12,200 meters above sea level for the former and between 17,000 and 25,000 feet, or between 5,100 and 7,100 meters for the latter. Private jets can fly higher, up to 51,000 feet, or 15,500 meters.
But why go so high? To get away from the reliefs, pass over theand ? Yes, but mainly for reasons of density of . The higher in altitude, the less the air in fact opposes to the plane and the more efficient the engines. The plane and will be able to fly faster. However, be careful, planes cannot climb indefinitely. And the cruising altitude which will be finally chosen will result from a clever compromise between various constraints.
Many constraints to take into account
Thus the distance to be covered can influence the. A plane that only has half an hour to fly in the air will indeed have no interest in trying to fly too high. Otherwise, he would hardly have time to reach his landing before he would have to descend to prepare for his landing.
Propeller planes, on the other hand, are slower. They don’t have thenecessary for high altitude flight. Another factor to consider: the weight of the device. A large carrier filled with fuel, in fact, will not be able to exceed 30,000 feet at the start of the course.
Thealso influences the choice of a cruising altitude. We will preferably look for from that will push the plane. And we will avoid , the and others by adapting its flight altitude.
Fighter planes and other peculiarities
Thewhich are much faster than airliners fly a notch higher. At around 65,000 feet for the F15, over 78,000 feet for the MIG-31 or even around 98,000 feet for the X-2 for example.
Finally, note that some regulations also constrain flight altitudes. Thus towns and gatherings of people cannot be overflown at a height of less than 1,000 feet. Pilots flying withoutapproved aeronautics – so-called VFR flights as visual flight rules (visual flight) – are not permitted above 11,500 feet. In addition, they must position themselves at altitudes corresponding to flight levels (FL) ending in 5. Knowing that 11,500 feet correspond to FL115. IFR flights – as instrument flight rules or instrument flight – must be positioned at FL ending in 0. And the semicircular rule is that planes flying west cannot fly at the same altitudes, FL even if we consider only the first two digits, as planes flying east, FL odd if we always consider only the first two digits.