Garmin G5 Maintenance Manual page 52

NOTE
It is important that all actions are carried out in the order and at the precise elapsed time as
specified in the prepared test sequence.
6. After the "Begin test sequence" appears, wait approximately five seconds and perform each of the
actions listed in the test sequence table. Refer to APPENDIX D for an example of a test
sequence.
7. When the test sequence is completed, wait approximately five seconds and then select "Done" to
complete the test.
The G5 informs the operator if the installation has passed or failed the magnetometer interference test.
The results displayed indicate the worst case percentage of limit and the time at which it occurred. If the
test passes, no further action is required.
If the test fails, the installation should be considered unreliable until the source of magnetic interference
is identified and remedied. The magnetometer interference test must be repeated until passed. When the
magnetometer interference test fails, record the magnetometer maximum deviation value and its
corresponding timestamp. Compare the corresponding timestamp with the prepared test sequence to
identify which action produced the problem.
Two common reasons for a failed magnetometer interference test are:
1. New equipment is installed in close proximity to the GMU 11 magnetometer.
2. An existing or new electronic device has become grounded through the aircraft structure instead
of via the proper ground wire in a twisted shielded pair, especially if the ground return path
through the aircraft structure passes near the GMU 11.
Garmin G5 Electronic Flight Instrument Part 23 AML STC Maintenance Manual
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190-01112-11
Rev. 7