Mach Number Explained: What It Is and Why Pilots Use It
Pilot Institute
JULY 11, 2025
When you reach around 36,000 feet (11,000 m) near the tropopause, the temperature stabilizes at around -56.5 °C. That’s the speed your airspeed indicator shows based on ram air pressure in the pitot tube. For most aircraft with highly cambered wings or thick profiles, airflow accelerates over the top of the wing.
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