Be Prepared to Deal with the High DA Blues

It's vital for a pilot to know what to expect when the density altitude rises.

Wednesday, January 17, 2024 at 05:03 PM ET

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Many pilots have very little experience with mountain flying, so their familiarity with high density altitude is limited as well. [Adobe Stock]

Key Takeaways:

Density altitude (DA) is pressure altitude corrected for nonstandard temperature and humidity, caused by high elevation, temperature, and/or humidity, and significantly degrades aircraft performance by increasing takeoff distance and reducing climb rates.
Pilots must calculate DA using tools like E6Bs, charts, or online calculators, then meticulously factor it into aircraft performance calculations from the POH/AFM, always applying conservative estimates.
Respecting and understanding DA is crucial for flight safety, as its effects can increase rapidly; pilots should train for these conditions and be prepared to make conservative decisions, including postponing flights.

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In the winter, pilots can get themselves in trouble by not recognizing when MVFR degrades into IFR conditions or when it gets so cold that ice forms on an aircraft in flight. In the summer, it’s high temperatures and high humidity that can rob an aircraft of performance. Yes, I am referring to density altitude—throw in a high-elevation field, and you have the trifecta of variables affecting several phases of flight.

Density altitude robs an aircraft of its performance, and if the pilot isn’t aware density altitude is present, they can run out of runway and options at the same time. You shouldn’t necessarily fear density altitude, but you should respect it, and know what to expect from your airplane.