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Revision A5
HXr Installation Manual GRT Avionics
If errors of greater than 30 degrees are observed, see section 4.3 to troubleshoot.
4.5 Magnetometer Calibration Procedure
The magnetometer must be calibrated before the first flight of the aircraft. Magnetometer
calibration is required to achieve accurate magnetic heading readings. This calibration corrects for
errors induced by magnetic disturbances local to the sensor, such as ferrous metal objects.
NOTE: The AHRS will not allow magnetometer calibration to be initiated if the airspeed is greater
than 50 mph to prevent inadvertent selection while in flight. If calibration is successful, the existing
calibration data (if any) will be replaced with the new corrections.
The Magnetometer Calibration page will help guide you through this procedure with its on-screen
menus and prompts.
1. Point the aircraft to magnetic north, in an area without magnetic disturbances, such as a
compass rose.
A simple means of pointing the airplane toward magnetic north is to taxi the airplane slowly
and use the GPS ground track to determine when you are taxiing in a magnetic north direction.
Make small corrections to the direction of travel of the airplane, and continue to taxi for several
seconds for the GPS to accurately determine your ground track. The GPS cannot determine
your track unless you are moving.
2. After the aircraft is positioned accurately, turn ON the EFIS. (If it was already on, then turn it
OFF, and then back ON again.)
3. Allow at least 1 minute for the AHRS to fully stabilize.
4. Press the MORE soft key, then the SET MENU soft key. Scroll to and select AHRS Maintenance.
Scroll to and select Magnetometer Calibration field on this screen.
5. Press Start soft key.
6. The first question is “Are you sure?” Press YES if you are sure.
7. Verify the airplane is still pointed to magnetic north. Answer the question “Are the aircraft,
AHRS, and magnetometer pointing to magnetic north?” with YES. A message will appear at
the bottom of the screen indicating the system is waiting for the gyros to stabilize.
8. As soon as the message “Calibration in Progress” is displayed (within 15 seconds), rotate the
aircraft 360 degrees plus 20 degrees in a counter-clockwise manner (initially towards west).
The airplane does not need to be rotated in place, but simply pulled or taxied in a circle. The
airplane must be rotated completely through 360 degrees, plus an additional 20 degrees past
magnetic north, within 3 minutes after initiating the calibration. The airplane should be rotated
slowly, such that it takes approximately 60 seconds for the complete rotation.