What is IAS?
Indicated Air Speed. The speed indicated on the airspeed indicator. Affected by altitude, and errors in the instruments. Instrument error is different in every aircraft.
what is CAS
Calibrated airspeed. Converted from IAS from a chart.
What is TAS
True airspeed. The actual velocity of the airplane. Derived by correcting for the difference in air density of the aircraft relative to the pressure at sea level. TAS will increase the higher the aircraft is relative to sea level. TAS will only equal IAS at sea level, and it is always higher.
What is GS
Ground speed. An aircraft’s speed over ground. Calculated by adding the tailwind to or subtracting the headwind from the TAS. GPS can give GS.
Why is airspeed critical?
Ensuring enough airflow over the wings to prevent stalling the aircraft or overstressing the airframe
How do aircraft’s measure speed?
Pitot-static system that measures the total air pressure the aircraft experiences and compares that to a static air pressure sensor on the aircraft. The difference in pressure can indicate the IAS (indicated airspeed)
What is a pitot tube?
It measures total air pressure, it’s hollow tubes that face in the direction of travel
What’s a static port
Static ports measure the static pressure of an aircraft’s environment. Holes on the surface of an airplanes fuselage that are parallel to airflow an aircraft experiences when flying.
