The heading indicator (also known as the directional gyro, or DG; sometimes also called the gyrocompass, though usually not in aviation applications) displays the aircraft’s heading with respect to geographical north. Principle of operation is a spinning gyroscope, and is therefore subject to drift errors (called precession) which must be periodically corrected by calibrating the instrument to the magnetic compass.
Features:
- operating voltage: 14 ± 10% V DC
- ambient temperature: -40 – +50 °C
- ambient relative humidity: no more than 95%
- vibration strength: 1.5g
- working range: indicating heading angle within the range of 360°
- accuracy: the drift error is not more than 4°/10 min
- operating current is not more than 0.72A
- rated Rotating speed is 22000 turns per min: it warns when power-off the rotating speed is below 70% of the rate rotating speed
- the insulating resistance between the power and case is not less than 20M?