Have you ever wondered while traveling in an airplane that why do airplanes fly at a height of 30 thousand feet or above? Well, airplanes don’t always fly at such high altitudes. You may have heard the captain of the airplane saying that we have reached the cruising altitude of 36,000 feet before switching off the seat belt sign. Not all but many of you must have thought this question while flying, so do we. That’s why we interviewed a few commercial pilots and asked them the same questions. The findings of these interviews revealed some interesting facts which we are going to present below.[irp]
First, there is always an ideal altitude for flying and the higher is altitude, the air gets thinner. Basically, this is good and bad at the same time. The good thing is that, there is less drag faced by the plane and thus low fuel consumption to hit the same speed. The bad thing is that at higher altitudes, the oxygen is less to combust with fuel thus less power is generated. As a matter of fact, a long climb is required to reach high altitude, which in turn burns more fuel. A smart and efficient pilot always finds a sweet spot from where he or she can fly as fast as possible without burning much fuel.
Secondly, there are also jet routes or in general, we can say them highways in the sky. ATC (Air Traffic Control) uses these jet routes to separate planes by a certain altitude or difference. Generally, this difference is 1000 feet vertically. By using these jet routes, they adjust the air traffic flow. Despite the vast sky, “Traffic Jams” do occur in the sky. When bad weather or thunderstorms build up, ATC is left with only a few suitable crossing points at specific altitudes in hundreds of miles and it depends on ATC to handle all the traffic through these one or two windows.
As there are jet routes in the sky and ATC controls these routes. There are altitudes which are considered as ideal but these ideal altitudes vary from airplane to airplane. Generally, the ideal altitude ranges from 30000 feet to 40000 feet. Almost all airplanes follow this ideal altitude height.
These ideal altitudes are determined to keep in view several factors including flight’s direction, duration, and the turbulence. There are few rules for safe flying. These rules are observed while flying. The rule of Cardinal Direction Altitude states that all commercial airliners traveling towards East, Northeast, Southeast and one degree short of South will fly at odd altitudes like 31000 feet, 33000 feet etc., whereas those airliners flying in all other directions will fly on even altitudes i.e. 32,000 feet to 34,000feet. Air traffic and its altitude are also affected by the CAT or Clear Air Turbulence as well. Whenever any pilot reports any such problem, the ATC uses such information and reports to steer other flights above or below.[irp]
There are Airline dispatchers which are hired by the carrier and they generally work in the headquarters of the company. These dispatchers control the planning and execution of all the flights of their company. They always keep track of the flights that where they are, where they are going, their weight and fuel and allocate them specific routes. Most of all, they calculate an ideal altitude for all flights and request the ATC, who then try to accommodate such requests when they give clearance to the pilot for a takeoff.