1
The reserve course system consists of three units, course gyro (AC driven), course amplifier and course indicator.

2
The course gyro, which is placed in the aircraft's fin, consists of a gyro supported by two gimbals, the wave gimbal and the course gimbal.

3
The gyro is basically set and monitored by a magnetic detector (course finder) which senses the direction of the earth's magnetic field.

4
The detector emits a voltage that varies with the angular deviation from the compass line. The voltage is amplified and applied to the turning motor course which causes the gyro to precede. This continues until the gyro's heading gimbal is aligned with compass north, when the voltage from the detector ceases. In this way, the gyro is monitored so that the course gimbal is always aligned with compass north.

5
A prerequisite for the gyro to show the correct course is that the wave gimbal is always in the horizontal plane. This is taken care of by an electrolytic pendulum which senses the deviations of the wave gimbal from the horizontal plane. If there is a deviation, a voltage is generated which is amplified and applied to the rotary motor wave, which in turn causes the gyro to precede so that the deviation ceases.

6
Through the processes described above, the gyro is monitored in course and yaw, so that the course gimbal is always aligned with compass north, regardless of the aircraft's movements.

7
On the heading gimbal there is a heading solenoid that emits a voltage that is dependent on the angle difference between the heading gimbal and the gyro stand (the longitudinal axis of the aircraft). Voltage is applied to the rate indicator's torque generator, which in turn turns the rate pointer.

8
The course indicator basically consists of an electric element on the rotor shaft of which the course indicator is attached. The pointer indicates the heading angle against a fixed scale. The course scale has graduation marks every tenth degree and numbers every thirty degrees.

9
On the lower left part of the indicator there is a push button for quick stabilization of the gyro. When this momentary is pressed, the gyro is set at a speed of 60°/min at the same time as a light in the push button lights up as an indication that rapid stabilization is in progress. The longest time for rapid stabilization is 3 min. In connection with the start of the plant (generator or BRAGG connection), however, if the button is kept pressed all the time, such an adjustment of the gyro is obtained that the course error after about 30 sec is less than 5°.