Maintenance - Garmin G3X Installation Manual

11.8 Maintenance

Per Part 43 Appendix E, paragraph (b)(2), Garmin specifies a test procedure equivalent to part 43
Appendix E, paragraph (b)(1) with two exceptions. The tests of sub-paragraph (iv)(Friction) and (vi)
(Barometric Scale Error) are not applicable because the digital outputs of the GSU 73 are not susceptible to
these types of errors.
A GSU 73 Field Calibration Tool can be used to adjust the calibration of GSU 73 units that have failed the
14 CFR Part 43 Appendix E tests due to altitude drift. Please contact a local Garmin dealer for more
information.
The GSU 73 utilizes an Earth magnetic field model which is updated once every five years. This IGRF
(International Geomagnetic Reference Field) update is expected to be available from Garmin by July 1 of
2015 and every five years thereafter, so long as the GSU 73 remains a Garmin –supported product. The
IGRF model is automatically updated with a GDU 37X software update. Alternatively, the IGRF model
can be updated by the end user via the Garmin website (www.garmin.com), it is not necessary to return the
GSU 73 to Garmin for this update. Otherwise maintenance of the GSU 73 is 'on condition' only.
G3X Installation Manual - GSU 73 Installation 190-01115-01
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