What is Density Altitude?

April 17, 2019 Monica Devlin Comments

While many of us don't think about density altitude in our everyday lives, it impacts the environment and even how airplanes perform while in the air. With dense air, nitrogen and oxygen are tightly packed together to make the surrounding air heavier than other locations. Air density varies depending on where you're located in the world, but temperature and altitude are two primary factors that influence density altitude.

The Relationship Between Temperature and Altitude

As altitude and temperature increase, density altitude increases along with it. Humidity is also a factor with density altitude, although its effect is much less significant than temperature and altitude. In terms of aviation, density altitude is how the airplane "feels" like it's flying.

For example, airplane acceleration is slow going down the runway on a hot and humid day. The plane also needs to move faster and climbs slower when density altitude is high. With this key knowledge in mind, pilots can make smart decisions when it comes to takeoff, flying, and landing airplanes.

How Thin Air Impacts Airplanes

Thin air at high density altitudes reduces force on the lift because it applies less force on the wings. It also reduces the engine's power because there is less air to mix with fuel. This combination often results in dramatically lower engine performance than in environments without thin air.

When it comes to flying in thin air, one major influencer that will impact airplane performance is horsepower.

Horsepower and Density Altitude

Density altitude is known for reducing horsepower in aircraft engines. For example, a normally-powered airplane will lose 3.5% of its horsepower for every 1,000-foot increase in altitude. This decrease in horsepower will force the pilot to consider the number of people flying in the airplane as well as the amount of gas.

While it's clear that density altitude has a significant impact in the world of aviation, how do you measure it to ensure a stress-free flight experience?

Measuring Density Altitude

Devices such as Kestrel Meters can monitor levels such as temperature and humidity, giving you a better insight into density altitude and any complications that may associate with it. It can prepare you to help make decisions such as:

Flying early in the morning or later in the evening when temperatures are lower.
Ensuring the aircraft's weight is at 90% of the gross maximum weight of flying in high-density altitude conditions.
Don't fill the tank to the top.
Make extra fuel stops.
Take shorter flights.

Fly Safe with Kestrel Weather Meters

By having Kestrel weather trackers on hand, you're sure to enhance your flight experience by having a bird's-eye view of current weather conditions---all at the touch of a finger.

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Monica Devlin