Revision A9 29
GRT Avionics Mini-X Installation, Setup & User Manual
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.
It is also possible to orient the airplane to magnetic north using the magnetometer itself. This
technique is more accurate assuming the magnetic disturbances from the airplane are minimal
in the north direction. We recommend using this technique first, performing this calibration,
and then validating the accuracy of the magnetic heading by taxiing the airplane and
comparing the EFIS heading to the GPS ground track (both are displayed on the PFD.
2. After the aircraft is positioned accurately, turn ON the Mini. (If it was already on, then turn it
OFF, and then back ON again) and allow at least 1 minute for the AHRS to fully stabilize.
3. Verify the PFD screen shows “HDG” next to the 3-digit heading display at the top-center of
the screen (indicating good magnetometer communication), and the heading is reasonable
(within about +/- 30 degrees of 360).
4. Access Set Menu > AHRS Maintenance. Scroll to and select Magnetometer Calibration field
on this screen.
5. Press Start soft key. The first question is “Are you sure?” Press YES if you are sure.
6. 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.
7. 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 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.
8. If calibration is successful, the AHRS will re-start itself automatically, and begin using the
corrections. While re-starting, the AHRS will not provide data. This will result in the AHRS data
disappearing from the display unit for about 10 seconds.
9. If calibration is unsuccessful, one of two things will happen. In either case, the calibration
procedure must be repeated.
a. If the airplane is rotated too rapidly, the calibration will not end after the airplane has been
rotated 380 degrees.
