Directional Gyro (DG) is a navigation instrument that provides information about the heading or direction of the aircraft based on the gyroscopic principle.

Unlike magnetic compasses that are susceptible to disturbances from the earth's magnetic field and unstable aircraft movements, DG provides a more stable and accurate heading.

​Directional Gyro Indicator

The main problem is that this instrument has no inclination to find the Earth's magnetic north, so it must be manually adjusted to match the magnetic compass every 15 minutes while the aircraft is in straight and level flight.