- What is a high density altitude?
- Density altitude above 8,000 ft is generally considered high. At a 5,000 ft elevation airport on a 35C day, density altitude can exceed 9,000 ft - meaning your aircraft performs as if it were at 9,000 ft even though you are at 5,000 ft. Takeoff roll increases and climb rate decreases significantly.
- How do you calculate pressure altitude?
- Pressure altitude = field elevation + (29.92 - altimeter setting) x 1,000. With QNH 29.62 at a 5,000 ft airport, pressure altitude is 5,300 ft. Set 29.92 in the altimeter window and it reads pressure altitude directly. This calculator shows it alongside density altitude.
- How does temperature affect density altitude?
- Every 10C rise in temperature increases density altitude by roughly 600-700 ft above the pressure altitude. Hot summer days at high-elevation airports can produce density altitudes that exceed the aircraft's service ceiling or eliminate the safety margin for obstacle clearance.