Heading indicator
（重定向自Directional Gyro）
![A heading indicator in a small aircraft.](/Images/godic/202501/09/C172_heading_indicator5406.jpg")
The heading indicator (also called an HI) is a flight instrument used in an aircraft to inform the pilot of the aircraft's heading. It is sometimes referred to by its older names, the directional gyro or DG, and also (UK usage) direction indicator or DI.