Accidents involving degraded performance due to density altitude continue to plague pilots. The precise effects of temperature upon pressure altitude and related corrections are applied by all pilots, but the one additional ingredient in the mix that affects density altitude, namely humidity, is largely ignored. What are the approximate respective altitude corrections, in feet, for humid air at 100% relative humidity when the air temperature is 50 °F, 70 °F, 90 °F, and 100 °F ?
- 15 feet, 30 feet, 45 feet, 60 feet
- 80 feet, 120 feet, 160 feet, 200 feet
- 1.5 feet, 6.5 feet, 30 feet, 130 feet
- 350 feet, 740 feet, 1400 feet, 2500 feet
Answer : Believe it or not it’s choice D, the worst of them. There are formulas to calculate it, as well as some good online calculators. For further reading, try:
https://www.beaufort.usmc.mil/weather/density_altitude_calculator.htm
http://www.faa.gov/AVR/afs/news/archive/MarchApril2004/Humidity.htm
