Why Do Planes Fly Higher Than Lower?

Planes fly higher for several reasons, primarily to avoid weather phenomena, zero in on fuel efficiency, and maintain passenger safety. High-altitude flights help planes bypass low-altitude turbulence, dispatched by jet engines that perform better at higher elevations. In this article, we explore the detailed reasons behind why planes fly higher than lower.

Thrust and Airspeed Equivalency

In aviation, the wing is a device that converts the kinetic energy produced by engines into lift. When you increase thrust, you gain both airspeed and altitude. This relationship between airspeed and altitude allows pilots to ascend and descend by adjusting their thrust and angle of attack.

During a level flight, the aircraft's lift balances its weight, maintaining a constant airspeed. Consequentially, to descend, one reduces thrust, which keeps the airspeed constant but changes the flight path angle to a descent.

Jet Engine Efficiency at High Altitudes

Jet engines are optimized for high-altitude operations. At higher elevations, the air is thinner, which allows planes to achieve higher speeds and conserve fuel. Additionally, erupting winds aloft can provide beneficial tailwinds, enabling planes to avoid adverse weather conditions and turbulent surfaces.

Important Factors for High-Altitude Flight

Atmospheric Layers and Weather

Airplanes primarily fly in the stratosphere, specifically around 10-12 kilometers (33,000 to 39,000 feet), to avoid dangerous weather conditions such as rain, thunderstorms, and turbulence in the lower troposphere. The stratosphere offers smooth and stable flying conditions.

How Aircraft Fly and Factors Affecting Altitude

Factors such as thrust, drag, lift, and weight all play a role in determining the optimal altitude for a plane. Modern aircraft models can operate at different altitudes, but the weight and drag vary by plane, leading to different ideal heights.

Why Fly So High?

High-altitude flights offer several advantages:

Passing Traffic

Aircraft at high altitudes can avoid low-altitude traffic from other planes, helicopters, and birds. Higher altitudes help pilots avoid potential collision hazards.

Mitigating Crash Risks

Beyond 10,000 meters, aircraft can avoid mountainous regions, reducing the risk of collision with mountains like Mount Everest.

Fuel Efficiency and Cost

Thinner air at high altitudes allows aircraft to travel faster and consume less fuel. This efficiency not only reduces operational costs but also helps in maintaining lower passenger ticket fares.

Managing Climatic Conditions

Since all weather phenomena occur in the troposphere, high-altitude flights help pilots avoid sudden and severe weather changes, ensuring passenger safety.

Avoiding Turbulence

A study by the Flight Safety Foundation and Aviation Safety Network reported around 248 turbulent events worldwide, though the fatality rate is low. Flying at higher altitudes greatly reduces the risk of air turbulence and subsequent hazardous situations.

Conclusion

High-altitude flight is essential for aviation, offering significant benefits in terms of safety, efficiency, and passenger comfort. Understanding the reasons behind flying at higher altitudes helps us appreciate the intricacies of modern air travel. Whether it's to avoid low-altitude turbulence, benefit from jet engine efficiency, or mitigate crash risks, staying high in the sky is a key principle in ensuring smooth and safe air travel.