GRT Avionics, Inc.
May 2019
Sport SX Install. Manual
26
Rev. A
2. When the final instrument and magnetometer orientations are set, check the
uncorrected Magnetic Heading and then perform the Fine Magnetometer
Calibration, described in sections
5-11: Check the Uncorrected Magnetic
Heading
and
5-12: Fine Magnetometer Calibration Procedure
.
5-11: Check the Uncorrected Magnetic Heading
While the calibration procedure can remove errors as large as 127°, accuracy is improved
if the location chosen for the magnetometer requires corrections of less than 30°.
To check the accuracy of the uncorrected magnetic heading:
1. Scroll to Magnetometer Calibration on the AHRS Maintenance page and select it.
2. While on this page, rotate the airplane 360°. A red graph will appear on this page
showing the calculated errors.
If errors greater than 30° are observed, refer to the previous sections,
5-8: Setting AHRS
Orientation
and
5-9: Magnetometer Location Validation
, to ensure that the AHRS is
properly oriented and that the magnetometer is mounted in a valid location.
5-12: Fine 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.
*NOTE:
Before performing this procedure, be sure that the AHRS orientation and
magnetometer orientation have been set. If these are not performed, the magnetometer
calibration will produce inaccurate magnetic heading readings.
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
