How is the speed of a plane calculated when it’s on its cruising altitude?

Question

How is the speed of a plane calculated when it’s on its cruising altitude?

In: 8

Answer 1

There are multiple speeds.

There’s indicated airspeed, which is the speed on your dials.

There’s calibrated airspeed, which corrects for .. you guessed it. Instrument calibration.

There’s equivalent airspeed, which is calibrated airspeed plus math because air does funny things when you go *really fast*.

Then there’s true airspeed, which is equivalent airspeed corrected for temperature and altitude.

All the “airspeeds” measure your speed through the air. The air is usually also moving.

Then there’s ground speed, which is your true airspeed adjusted for the movement of the mass of air you’re flying in. It measures… your speed over the ground.