Garmin G1000 NXi Supplemental Maintenance Manual

Also see for G1000 NXi: Cockpit reference guide Pilot's guide Cockpit reference guide Reference guide Pilot's guide

Contents

G1000 Supplemental Maintenance Manual Page 7-36Textron Nav III Series Revision 3190-02128-04Compass Rose Evaluation of Magnetic Disturbances for MagnetometerCalibration Procedure (Optional)NOTEThe Magnetometer Calibration Procedure that follows in Section 7.10.3(Calibration Procedure B) must be carried out at a site that isdetermined to be free of magnetic disturbances. If it is unsure whetherthe site is ‘clean’, the technician should verify that the site is ‘clean’ byfollowing the guidance provided in Section 7.10.2. The technician mayskip Section 7.10.2 if the site condition is acceptable.Typically, a compass rose is an acceptable location to perform themagnetometer calibration procedure. However, because not allcompass roses are well maintained, even an existing compass roseshould be regularly evaluated using the method described here todetermine if it is free of magnetic disturbances. If evaluation of anexisting compass rose indicates that magnetic disturbances arepresent, then an alternative location must be found to perform theMagnetometer Calibration Procedure.A G1000-equipped airplane that has completed the pitch/roll offset compensation procedure(Procedure A-1, Section 7.10.1) can be used to evaluate a candidate site for magneticdisturbances and determine whether it is a suitable location to perform the magnetometercalibration procedure. The magnetometer calibration procedure itself contains the logic tosimultaneously survey the location for magnetic cleanliness while it is computing themagnetometer calibration parameters.In order to evaluate a candidate site, the Magnetometer Calibration Procedure must beperformed twice: once turning clockwise around the site, and once turning counter-clockwise.Both times, the procedure should be conducted as described in Section 7.10.3 of thisdocument, with the exception of the direction of turns around the site.NOTEAlthough Section 7.10.3 indicates that the Magnetometer CalibrationProcedure should be performed by making a series of clockwise turnsaround the site, the procedure can also be performed by makingcounter-clockwise turns for the purpose of evaluating the site formagnetic disturbances.If the PFD displays the “CALIBRATION SUCCESSFUL / SITE IS CLEAN” message uponcompletion of the Magnetometer Calibration Procedure in each clockwise and counter-clockwise direction, then the candidate site is sufficiently free of magnetic disturbances and isacceptable for performing the Magnetometer Calibration Procedure. It is important to obtainsuccessful result in both the clockwise and counter-clockwise directions to ensure that themagnetometer sweeps over a large enough area at the candidate site.If the PFD displays either the “MAG FIELD AT SITE NOT UNIFORM” or “MAG FIELD AT SITEDIFFERS FROM IGRF MODEL” message upon completion of the Magnetometer CalibrationProcedure in either of the two directions, then the site contains magnetic disturbances that aretoo large.