What do you need to know about Pressure Altitude and Density Altitude on the FAA Private Pilot Knowledge Test? Visit https://flightinsight.teachable.com/p... to learn more!

The air we fly in is never the same. The density is affected by altitude, air pressure, temperature, and humidity. We need an easy way to compare different conditions on different days so we can predict how well the airplane will perform.

This is what the International Standard Atmosphere is all about. It's a fantasy land, where the pressure and temperature are always the same no matter what.

In this fantasy land, the conditions are always:
Sea Level Pressure: 29.92 inches of Mercury
Temperature: 15°C at Sea Level
Lapse Rate: Temp drops 2°C for every 1000' of altitude

So Pressure Altitude is the altitude we'd be flying at in this fantasy land if we were experiencing a certain pressure. Density Altitude takes it a step further and gives us the altitude we'd be at in fantasy land under a given pressure AND temperature.

Pressure Altitude vs Density Altitude | Private Pilot Knowledge Test | FlightInsight