Magnetometer Interference Test Sequence Example - Garmin GDU 370 Installation Manual

Table 8-4. Magnetometer Interference Test Sequence Example
Elapsed Time Since Start
of Test (min:secs)
0:00
0:10
0:20
0:30
0:40
0:50
1:00
1:20
1:40
1:50
2:00
2:10
2:20
2:30
2:40
2:50
3:00
3:10
3:20
3:30
3:40
3:50
4:00
4:10
4:20
4:30
4:40
4:50
5:00
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 three magnetometer maximum deviation values and their
corresponding timestamps. A maximum deviation value greater than 5.0 milliGauss in either the X or Y
axes, or greater than 8.0 milligauss in the Z axis indicates a problem that must be resolved. Compare the
corresponding timestamps with the prepared test sequence to identify which action produced the problem.
Contact Garmin for assistance in resolving the problem.
Two common reasons for a failed magnetometer interference test are:
1) New equipment is installed in close proximity to the GMU 44 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.
G3X Installation Manual – Post Installation Checkout and Calibration Procedures
190-01115-01
Test begins
Aileron full right
Aileron full left
Aileron level
Flaps down
Flaps up
Landing gear up
Landing gear down
Speed brake up
Speed brake down
Navigation lights on
Navigation lights off
Landing lights on
Landing lights off
Taxi lights on
Taxi lights off
Landing + Taxi lights on
Landing + Taxi lights off
Strobes on
Strobes off
Recognition lights on
Recognition lights off
Turn on all wing-tip lights simultaneously (typically will include
navigation lights, recognition lights and strobe)
Turn off all wing-tip lights simultaneously
Beacon on
Beacon off
Pitot heat on
Pitot heat off
End of test
NOTE
Action
Page 8-23
Revision A