Density Altitude

Density Altitude

Density altitude is pressure altitude corrected for non-standard temperature. An airplane operating at different airports that, because of temperate and pressure variations have the same density altitude, will perform the same. Density altitude is a nearly direct representation of air density.

Lesson Notes

Air density determines your airplane’s performance. The more dense the air, the better the performance. The less dense, the worse the performance. Density altitude is a way of measuring and comparing air density.

If, for example, the density altitude is 4,000 feet, this indicates that your airplane will perform (regardless of your actual altitude) as if the airplane is at 4,000’ on a standard day. This is because density altitude is based on air density, which changes with temperature and pressure. On hot summer days at sea level, it is not uncommon to see density altitudes in the range of 2,000 to 3,000 feet. On similar days, airports at 7,000 feet may reach density altitudes upwards of 9,000 feet. If you’ve ever flown a low-powered airplane like a Piper Cub or Cessna 150 at 9,000 feet, you understand the performance hit you receive at such low air density. It can quite literally make it impossible to get your airplane off the ground.