Principles of Gyroscopic Instruments

Three of the six primary flight instruments use gyroscopes to provide pilots with critical flight information about the airplane's attitude, heading, and rate of turn.

Rigidity in Space and Precession

Gyroscopes work like spinning tops. They have two properties—rigidity in space and precession—that make them useful in flight instruments.The attitude indicator and heading indicator are based on a gyro's rigidity in space. Because a gyro resists being tipped over, it can provide a stable reference to the real horizon or to a specific direction.

The turn coordinator uses precession to display information about the direction and rate of turn.

Gyro Power

In most light airplanes, an engine-driven vacuum pump spins the gyros in the attitude indicator and the heading indicator. To provide a backup if the vacuum fails, the turn coordinator usually has a gyro spun by an electric motor.

TIP: To test your ability to fly after one or more instruments fail, you can hide certain instruments or make them unreliable. For more information, see the topic "Setting Instrument Options" in the Using Flight Simulator section of Pilot's Help.