Garmin G3X Installation Manual page 166

11. After the complete calibration is finished, a Done button will appear at the bottom of the
display, ensure that a CALIBRATION SUCCESSFUL message appears at the bottom of the
display, press the ENT Key to return to the GSU Status Page.
9.3.7 Site Evaluation of Magnetic Disturbances for Magnetometer Calibration
Procedure
As mentioned in Section 9.3.4, the Magnetometer Calibration Procedure (Calibration Procedure D) must
be carried out at a site that is determined to be free of magnetic disturbances.
Typically, a compass rose is an acceptable location to perform the magnetometer
calibration procedure. However, because not all compass roses are well maintained, even
an existing compass rose should be regularly evaluated using the method described here
to determine if it is free of magnetic disturbances. If evaluation of an existing compass
rose indicates that magnetic disturbances are present, then an alternative location must be
found to perform the Magnetometer Calibration Procedure.
A G3X-equipped airplane can be used to evaluate a candidate site for magnetic disturbances and
determine whether it is a suitable location to perform the magnetometer calibration procedure. The
magnetometer calibration procedure itself contains the logic to simultaneously survey the location for
magnetic cleanliness while it is computing the magnetometer calibration parameters.
The G3X-equipped airplane installation used to evaluate the site must have already completed the
pitch/roll offset compensation procedure (Procedure B). However, prior completion of the Magnetometer
Calibration Procedure (Procedure C) is not required.
In order to evaluate a candidate site, the Magnetometer Calibration Procedure must be performed twice:
once turning clockwise around the site, and once turning counter-clockwise. Both times, the procedure
should be conducted as described in Section 9.3.3 of this document, with the exception of the direction of
turns around the site.
Although Section 9.3.4 indicates that the Magnetometer Calibration Procedure should be
performed by making a series of clockwise turns around the site, the procedure can also
be performed by making counter-clockwise turns for the purpose of evaluating the site
for magnetic disturbances.
Page 9-26
Revision E
NOTE
NOTE
G3X Installation Manual – Post Installation Checkout and Calibration Procedures
190-01115-01