Adahrs And Magnetometer Ground Checks - Garmin G3X Touch Maintenance Manual

8.11.2 EIS Engine Run-Up Check
Always follow engine startup procedures as described in the Aircraft POH.
CAUTION
If the engine indications are not within operating specifications shortly after starting, IMMEDIATELY shut
down the engine and troubleshoot the problem. Failure to do so may cause engine damage.
Obtain an optical tachometer to monitor propeller RPM.
1. Place the aircraft in an open and clear area appropriate for an extended engine run-up.
2. Follow the engine start-up procedure as outlined in the aircraft POH. Adhere to the required
observations immediately following the start such as oil pressure within 30 seconds.
3. Verify the EIS RPM gauge(s) match the optical tachometer reading +/- 50 RPM.
4. Allow the engine to warm up and oil temperature to increase to at least 100°F.
5. Verify the alternator load meter (if installed) and battery charge/discharge ammeter (if installed)
indicate a positive load.
6. Perform individual magneto checks as specified by the aircraft POH. If the RPM does not drop as
expected when switching from both magnetos to one, the P-lead, ignition switch wiring, or
magneto timing is incorrect. Discontinue the test immediately and repair the ignition system.
7. Verify all EIS readings are consistent with normal operation performance in accordance with
aircraft type design, engine type design, and/or aircraft POH/AFM.
8. Verify all installed sensors and fittings are free of leaks.

8.12 ADAHRS and Magnetometer Ground Checks

This section contains the ground checks that may be performed on the magnetometer for ADAHRS
aspects of the G3X system.
8.12.1 Altimeter Check
The GDU 4X0 altitude displays must be verified per Title 14 CFR 91.411 and 14 CFR Part 43 Appendix
E, with the following exception to 14 CFR Part 43 Appendix E, paragraph (b)(1):

The tests of sub-paragraphs (iv) (Friction) and (vi) (Barometric Scale Error) are not applicable
because the digital outputs of the GSU 25D are not susceptible to these types of errors.
This procedure is recommended when the GSU 25D is removed and reinstalled/replaced or the pitot and
static system connections are disturbed.
8.12.2 Pitot-Static and Airspeed Tape Settings Checks
The following section verifies the correct operation of the GDU 4X0 altitude and airspeed display
functions. These tests require the use of a Calibrated Air data test set. When using a Calibrated Air data
test set, only simulate normal aircraft operating conditions, as defined in the aircraft Type Data
(POH/AFM) or other approved STC to avoid component damage.
Airspeeds above Vne should not be checked.
The aircraft or instrument manufacturer's data should be referenced for tolerances for this test where
available.
1. Connect the calibrated air data test set to the aircraft.
2. Apply power to the aircraft.
3. Verify all self-tests pass on the main startup screen.
4. Using the air data test set, increase the airspeed until the PFD airspeed tape pointer is at the
bottom of the white band (Vs0).
5. Verify that the pitot and static pressure settings used on the test set match what is displayed on
the GDU.
Maintenance Manual
G3X Touch EFIS Part 23 AML STC
Page 98
190-02472-02
Revision 2