Final answer:
The heading indicator is an instrument used in aviation to display the aircraft's heading. It operates based on the principles of gyroscopic stability and precession and is powered by either a mechanical vacuum system or an electric system.
Step-by-step explanation:
The heading indicator is an instrument used in aviation to display the aircraft's heading. It operates based on the principles of gyroscopic stability and precession. The instrument contains a gyroscope that spins at a high speed and remains oriented in space regardless of the motion of the aircraft. This allows the instrument to accurately indicate the heading.
In terms of power, the heading indicator is typically powered by either a mechanical vacuum system or an electric system. In mechanical systems, the gyroscope is driven by a vacuum pump, while in electric systems, the gyroscope is driven by an electric motor.