Commercial airplanes typically fly at an altitude of around 35,000 feet in order to strike a balance between operating costs and fuel efficiency.
Most commercial airplanes fly at an altitude of approximately 35,000 feet, which is equivalent to about 6.62 miles (10,600 meters) above the ground. This is quite impressive, considering that the top of a skyscraper is already considered tall!
Now, you might wonder why airplanes can’t just fly a few hundred meters above the ground, as long as they clear any obstacles like communication towers and skylines.
Well, the altitude at which airplanes fly is not randomly chosen. There are specific reasons why planes fly at certain heights in the sky. Let’s delve into the science behind why airplanes fly at high altitudes.
Air Resistance and Fuel Efficiency
One of the main reasons why commercial airplanes fly at high altitudes is because of air resistance. As the plane goes higher above the ground, the atmosphere becomes thinner, resulting in less resistance on the plane’s movement.
Flying at higher altitudes reduces air resistance for commercial airplanes. (Photo Credit: Pxhere)
The concept is quite simple—the more air molecules the plane has to navigate through, the more energy it requires, which leads to higher fuel consumption and operating costs. Moreover, the high altitude is extremely cold, around -55°C, which helps improve the efficiency of jet engines.
Cruising Altitude: The Optimal Level
Due to reduced resistance at higher altitudes, commercial airplanes can travel forward with minimal fuel usage. The typical cruising altitude for commercial airplanes ranges between 32,000 and 38,000 feet, with the optimal level being around 35,000 feet, commonly known as the cruising altitude.
A balance between operating costs and fuel efficiency is achieved at approximately 35,000 feet, which is why commercial airplanes usually fly at this altitude.
While commercial airplanes can ascend to 42,000 feet, surpassing that level can be risky. The air becomes too thin for the airplane to fly optimally, and there is a scarcity of oxygen, which hampers the functioning of fuel engine systems.
In 2004, the crash of Pinnacle airline flight 3701 occurred when the pilots flew the aircraft at altitudes higher than recommended. The plane lost control and crashed into a highway near Jefferson City after surpassing 41,000 feet.
Crash of Pinnacle airline flight 3701 in 2004 (Photo Credit: Aeroprints/Wikimedia Commons)
Avoidance Of Weather-related Events Like Thunderstorms
One of the main reasons why commercial airlines fly at an altitude of 6.6 miles is to avoid clouds and weather-related events such as thunderstorms. By flying at this height, they are able to have more stable air and minimize the risk of turbulence. If planes have to fly through clouds or storms, it can cause discomfort to passengers and even panic. However, pilots are trained to handle such situations and are expected to report them to air traffic control for assistance and advice.
For airlines, providing a smooth and comfortable flight experience to passengers is crucial.
Clearing Obstacles
Another reason why planes fly at higher altitudes is to avoid obstacles such as towers, buildings, and other structures on the ground. It is unsafe and impossible to navigate through these obstacles while flying a plane. The altitude at which planes fly is determined by the terrain, which can be significantly higher above sea level than the runway. Therefore, planes climb to an appropriate altitude to stay clear of any ground structures.
In most aviation authorities around the world, it is prohibited for commercial airplanes to fly below 1,000 feet unless there is an emergency. This rule is in place for safety and environmental reasons, including noise reduction. Commercial airplanes are known to be loud and noisy, especially when close to an airport.
At around 35,000 feet, airplanes reach the border between the troposphere and stratosphere. This region is relatively free of birds, insects, and microbes, reducing the risk of bird strikes.
Miracle On The Hudson
There have been numerous cases of bird strikes on airplanes, but one that gained significant attention is the US Airways Flight 1549 incident. On January 15, 2009, an Airbus 320 was struck by a flock of birds, causing both engines to fail. The pilot had to make an emergency landing in the Hudson River as there was concern about reaching an airport or a safe place nearby. Miraculously, the plane remained afloat, allowing for successful rescue operations and evacuation of all passengers. This incident became known as the Miracle on the Hudson. To learn more about bird strikes and how flying at higher altitudes can help prevent such incidents, watch our video below.
Airplane Safety Margin
Imagine yourself as the pilot of a commercial jet, flying just a mile above the ground, when suddenly something goes wrong. The plane starts descending rapidly, and you know that the problem can be fixed, but there’s not enough time to do so. In that moment, you would wish for more time…
Being at a higher altitude gives you that extra time to think, calculate, and take the necessary actions to ensure the safety of your passengers.
Private Jets and Helicopters
So far, we have discussed the advantages of commercial airplanes flying at high altitudes, such as reduced air resistance and fewer bird encounters. But what about private planes and helicopters? Well, private jets typically use a piston-powered single engine, similar to a car engine. This type of engine is designed for shorter distances and is not powerful enough to reach the same altitudes as commercial aircraft.
According to aviation experts, most private planes have a maximum altitude limit of 15,000 feet.
Besides the limitation of the engine, there’s another risk associated with flying at higher altitudes in these types of aircraft. As they ascend, the oxygen levels decrease, leading to hypoxia, which is a condition where tissues don’t receive enough oxygen. This can be life-threatening for both the pilot and the passengers.
Now, let’s talk about helicopters. They have a completely different design, using rotating blades instead of wings. As a result, their maximum altitude is usually below 10,000 feet.
Now you understand why commercial planes fly at an altitude of approximately 6.6 miles. Flying at this height provides optimal air pressure, a suitable environment, and most importantly, a safety margin for pilots in case of emergencies!