First, an adapter is mounted onto the fuselage and the CA-320A or CA-321A attached and secured to it. A quality test is performed which verifies the state of the local magnetic field.
Next, the CA-320A or CA-321A laser is aligned with the Laser Template, which has been placed at a specified datum point on the fuselage. The CA-320A or CA-321A is then secured to prevent further movement and the function switch is set to COMPASS. The technician may now read magnetic headings on the CA-320B or CA-321B.