GRT Avionics

About a year ago I had to replace my legacy dual AHRS and analog magnetometers with a dual adaptive AHRS and a single digital magnetometer. I've struggled to get an accurate heading readings from the new setup. Am I supposed to be performing the calibration on both display units or just one? I assumed just one, but I'm wondering if perhaps it's supposed to be both?

-John

Usually only one, but you need to make sure both AHRS are showing the same attitude (AHRS Maintenance, Set AHRS #1/#2 Orientation, adjust if necessary), and have the magnetometer orientation data stored (Set Magnetometer #1/#2 Orientation, Magnetometer Roll/Pitch). If both AHRS are wired to one screen, then "Magnetometer #2" means the magnetometer connected to AHRS #2, even though it's the same magnetometer. However, with two display units only the 2nd display may be able to perform these functions on AHRS #2. The orientation data is separate for each AHRS and the magnetometer orientation is stored separately in each AHRS so you have to adjust/calibrate the orientation data for each one. Then make sure they synchronize the magnetometer calibration data. The "Magnetometer Cal Data Sync" page will show whether it understands the magnetometer is shared and the status of the sync between AHRS. On some older AHRS and magnetometers, the system doesn't automatically understand they are shared, so in that case you have to tell the system that each AHRS uses Mag Number 1 in the Cal Data Sync menu.