Gyroscopic Instruments

Overview

• Gyroscopic instruments: Attitude Indicator, Heading Indicator, Turn Coordinator.
• Rely on gyroscopes to function.
• Driven by air suction or electricity.
• Provide information such as pitch, bank, yaw, and heading.

Gyroscope Principles

• Rigidity in Space: Gyro remains in a fixed position in the plane it spins.
• Precession: Gyro reacts 90 degrees ahead in the direction of force, can cause errors (e.g., drift).
• Corrections for precession errors are available.
• Gyros must spin at high speed, powered by air or electricity.

Power Sources

• Attitude and Heading Indicators: Typically air-powered.
• Turn Coordinator: Typically powered by electricity.
• Different power sources are used for safety redundancy.

Attitude Indicator

• Indicates aircraft orientation relative to Earth.
• Displays pitch (fore and aft tilt) and bank (side-to-side tilt).
• Useful in poor visibility or at night.
• Features artificial horizon and miniature airplane.
• Degrees of bank and pitch marked in increments.
• Gyro spins around the vertical axis; connected to the instrument display.
• Errors may occur if the pitch/bank is excessive or if vacuum is insufficient.

Heading Indicator

• Displays heading based on a 360-degree azimuth (5-degree increments).
• Requires realignment at the start of flights using the magnetic compass.
• Can drift due to friction and precession; needs periodic realignment.
• Gyro oriented on the horizontal axis.

Turn Coordinator

• Indicates rate and quality of turns; backup for bank information.
• Miniature airplane displays rate of turn.
• Inclinometer shows aircraft coordination with a ball inside a kerosene tube.
  • Slip: Not enough rudder for the bank.
  • Skid: Too much rudder for the bank.
• "Step on the ball" technique to correct slips/skids.
• Typically powered by electricity.
• Red flag indicates power failure.
• Gimbal is tilted 30 degrees for additional roll rate measurement.