Calibration Procedure B: Magnetometer Calibration; Figure 5-1. Fixed-Wing And Helicopter Position Examples - Garmin GSU 75 Series Installation Manual

5.5 Calibration Procedure B: Magnetometer Calibration

NOTES
Calibration Procedure A-1 or A-2 must be successfully completed prior to Calibration
Procedure B. If either Calibration Procedure A-1 or A-2 is repeated, then Procedure B
must also be repeated.
Calibration Procedure B 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 5.9.
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°). The aircraft should be positioned to
enable clockwise turning around the compass rose. For fixed-wing aircraft, it is best to offset the aircraft
position to the left (west) of the North/South axis. For helicopters, it is best to position the aircraft in the
center of the compass rose. These positions are depicted in Figure 5-1.

Figure 5-1. Fixed-wing and Helicopter Position Examples

With the aircraft stationary, initiate the GSU 75 AHRS magnetometer calibration procedure as follows:
1. If the MFD and PFD(s) are not both in configuration mode, proceed with Steps 2 through 4. If the
MFD and PFD(s) are already in configuration mode, skip ahead to Step 5.
2. Enter the configuration mode by holding the ENTER key on each display while applying power.
Release the ENTER key when the words INITIALIZING SYSTEM are displayed on each display.
3. On the PFD, turn the FMS large knob clockwise until the GSU Page Group is selected.
4. At the GSU Page Group, turn the small FMS to display the GSU/GMU Calibration page.
190-01639-00
Rev. 6
The document reference is online, please check the correspondence between the online documentation and the printed version.
GSU 75 ADAHRS Installation Manual
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