# Density Altitude and Calculations MET

Density Altitude, or DADA —1) Altimetry: Density Altitude2) Approaches: Decision Altitude, is **the point in ISAISA —International Standard Atmosphere that replicates the real world density conditions** as you find them on a particular day. So **high DADA —1) Altimetry: Density Altitude2) Approaches: Decision Altitudes are bad**, as the higher you go in ISAISA —International Standard Atmosphere, the lower the density and the worse your aircraft wings and engines will perform.

To get from altitude (technically, pressure altitude) to density altitude, we use the formula $DA = <span data-acronym="PA">PA<span class="definition-text multiple-definitions"><span class="term">PA —</span><span class="definition-variation"><span class="numeral">1)</span> <span class="disambiguation">Approaches</span>: Precision Approach</span><span class="definition-variation"><span class="numeral">2)</span> <span class="disambiguation">Altimetry</span>: Pressure Altitude</span></span></span> + (120 * <span data-acronym="ISA">ISA<span class="definition-text"><span class="term">ISA —</span>International Standard Atmosphere</span></span> Deviation.)$ So if the temperature is higher than ISAISA —International Standard Atmosphere, this reduces the density, which means you have to go higher in ISAISA —International Standard Atmosphere to replicate the conditions, meaning a higher DADA —1) Altimetry: Density Altitude2) Approaches: Decision Altitude.

The only real mistake that can be made (although an easy one) is to get the sign of the ISAISA —International Standard Atmosphere deviation wrong and end up applying the correction the wrong way. This answer will certainly be one of the incorrect options on the exam.