Which pressure operates the Airspeed Indicator in the Cessna 172?

The airspeed indicator in the Cessna 172 operates using both static pressure and dynamic pressure. The design of the airspeed indicator uses a diaphragm that responds to these two types of pressure.

Static pressure is the atmospheric pressure surrounding the aircraft, which is measured from static ports located on the aircraft's fuselage. This pressure is essential for providing a reference point.

Dynamic pressure, on the other hand, is created by the airflow over the aircraft as it moves through the air. It is derived from the difference between total pressure (which includes both static and dynamic pressures) and static pressure. This dynamic pressure is what allows the airspeed indicator to display the aircraft's speed through the air, as it reflects how much air is impacting the aircraft.

Combining both static and dynamic pressures enables the airspeed indicator to give an accurate reading of the aircraft’s airspeed. This dual operation is crucial for flight operations, as it allows pilots to understand their performance and make necessary adjustments.