Aircraft Alignment - Garmin GDU 370 Installation Manual

8.3.3 Calibration Procedure C: Magnetometer Calibration
Calibration Procedure B must be successfully completed prior to Calibration
Procedure C.
Calibration Procedure C must be carried out at a location that is determined to be free of
magnetic disturbances, such as a compass rose. Attempting to carry out this maneuver on
a typical ramp area will not yield a successful calibration. The accuracy of the AHRS
cannot be guaranteed if this calibration is not performed at a magnetically clean location.
A method for evaluating the magnetic disturbances at a candidate site is described in
Section 8.3.7.
Taxi the aircraft to a site that has been determined to be free of magnetic disturbances. Ensure that there
are no nearby magnetic materials on or near the perimeter of the site. If unavoidable, maneuver the
aircraft to keep the magnetometer from passing within twenty feet (6.1 meters) of such objects.
Additionally ensure that vehicles or other aircraft are an adequate distance [forty feet (12.2 meters)] away
from the aircraft under test.
At the site, align the aircraft to a heading of magnetic north (±5°). It is best to offset the aircraft position
to the left (west) of the North/South axis to allow turning clockwise around the site as indicated in Figure
8-2.
With the aircraft stationary, initiate the GSU 73 AHRS magnetometer calibration procedure as follows:
1. Enter configuration mode by holding down the left-hand softkey while powering on the GDU
37X (if needed).
2. Use the FMS Joystick to select the GSU Page (if needed).
Page 8-10
Revision A
NOTE
NOTE
Figure 8-2 – Aircraft Alignment
G3X Installation Manual – Post Installation Checkout and Calibration Procedures
190-01115-01