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Pressure / Density Altitude – More / Less Dense – High / Low Temperature Help

Asked by: 1746 views General Aviation, Weather

I haven't yet been able to crack a consistent memory aid for how to remember the specifics of pressure altitude, density altitude, how temperature affects density and high /low temperature vs high/ low elevation....

Anyone have a mnemonic or acronym or phrase to help me with this? Something is just not clicking and for the life of me I can't consistently remember where it's more dense vs less dense, how that relates to density and throw pressure altitude into the mix, the topic as a whole is something I'm struggling to master. Any tips?

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2 Answers



  1. awair on Jul 11, 2022

    There is boldmethod page that describes this well, no mnemonics but good illustrations that help it stick…

    https://www.boldmethod.com/learn-to-fly/performance/density-altitude/

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  2. mjc123 on Dec 18, 2022

    To remember the relationship between temperature and density, it can be helpful to think of the phrase “hot air rises.” Hot air is less dense than cold air, so it will rise in the atmosphere. When the air temperature is high, the density of the air will be lower, resulting in a higher density altitude.
    To remember the relationship between altitude and density, you can think of the phrase “thinner air at higher altitudes.” As you climb higher in the atmosphere, the atmospheric pressure decreases, resulting in less dense air. This means that the density altitude will be higher at higher altitudes.
    One acronym that can help you remember the relationship between these variables is “HALD,” which stands for “Hotter Air Less Dense.” This acronym can help you remember that high temperatures and high altitudes both result in less dense air and therefore higher density altitudes.

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