Maintenance Manual 190-02472-02G3X Touch EFIS Part 23 AML STC Revision 2Page 1005. Calculate the heading errors by subtracting the displayed (B) value from the actual (A) value foreach of the headings in Table 8-3.6. If all calculated heading errors displayed on the PFD are at or within +/-10° from the surveyedheading, the installation is acceptable, and no further work is required to correct the GMU 11installation.7. If a Heading Error (A-B) is greater than +/- 10°, calculate the average error by adding all errorsand dividing by 12. This is the angle by which the GMU 11 must be physically rotated to correctthe installation.8. Modify the installation to rotate the GMU 11 by the amount calculated in the previous step. Whenlooking down at the GMU 11, rotate clockwise for positive values, and counterclockwise fornegative values.9. After physically correcting the GMU 11 installation, repeat the procedures in Sections 0 and8.12.3.Table 8-3 – Heading Verification – ADAHRS CheckHeading (A) Displayed ADAHRSHeading (B)Heading Error (A-B) Standby CompassHeading360° (North)30°60°90°(East)120°150°180°(South)210°240°270°(West)300°330°8.13 Garmin GFC 500 AutopilotFor aircraft equipped with Garmin GFC 500 autopilot system, perform interface checkout of the autopilotin accordance with procedures outlined in GFC 500 Part 23 AML STC Installation Manual 190-02291-00.8.14 Non-Garmin Autopilot InterfaceBefore proceeding with the autopilot interface tests, verify the PFD has been properly configured for theautopilot (and flight director, if applicable) that is installed. For configuration instructions referenceAppendix B.5. and the G3X Touch EFIS Part 23 AML STC Installation Manual (190-02472-01). Onlythose interfaces which are directly affected by the G3X Touch STC are covered by this manual; if anyother autopilot modifications were performed, they are outside the scope of this STC and must bechecked in accordance with the autopilot installation manual.WARNINGIt is important that the PFD be properly configured in order to prevent damage to the autopilot computer.
