International Standard Atmosphere(ISA)
Definition
A model atmosphere used for aircraft performance calculations. At sea level: 15 degrees C, 29.92 inHg, and temperature decreases at 2 degrees C per 1000 feet. ISA deviation affects aircraft performance.
Why International Standard Atmosphere Matters for Pilots
Weather concepts like International Standard Atmosphere appear frequently on both FAA and EASA knowledge exams. More importantly, understanding International Standard Atmosphere helps pilots make sound go/no-go decisions and avoid hazardous conditions in flight. Weather-related accidents remain a leading cause of general aviation incidents.
Exam Tip
This concept is commonly tested in meteorology-related questions on FAA and EASA exams. Make sure you can explain International Standard Atmosphere in your own words for the oral exam. Practice applying this concept to real-world scenarios, not just memorizing the definition.
Related Terms
Density Altitude
Pressure altitude corrected for non-standard temperature. It represents the alti...
Pressure Altitude
The indicated altitude when the altimeter is set to 29.92 inHg (1013.25 hPa). Us...
Temperature Lapse Rate
The rate at which air temperature decreases with altitude. The standard lapse ra...
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