Composite Nav Calibration; Backup Battery Test - Garmin GI 275 Installation Manual

5.7.3

Composite NAV Calibration

If a Composite NAV connection is interfaced to a GI 275, the displays must be calibrated to each
individual NAV radio using the following procedure:
1. Power on the GI 275 in Configuration mode and then power on NAV1.
2. Navigate to the Analog NAV Calibration page (Calibration/Test → Analog NAV).
3. Touch the Localizer button.
4. Use an appropriate NAV tester to generate a localizer signal with 0.155 DDM left or right, and
tune the NAV radio to the test frequency.
5. Touch the Calibrate button and then the OK button.
6. Wait for the calibration to complete (approximately 6 seconds) and touch the OK button.
7. Verify that the DDM readout is 0.155 ± 0.010.
8. If the DDM readout is not within the specified value, adjust the Gain value manually so that the
readout is 0.155 ± 0.010 DDM.
9. Touch the Back button and then the VOR button.
10. Use a NAV radio tester to generate a 0° FROM radial VOR signal, and tune the NAV radio(s) to
the test frequency.
11. Press the Calibrate button and then the OK button.
5.7.4

Backup Battery Test

This procedure will analyze the voltage and discharge qualities of the installed backup battery. The
procedure is required to be completed when a backup battery is installed in the system. A fault indication
message will be displayed in Normal mode until this procedure is completed. The Backup Battery Test
page will only be available if a backup battery is configured on the Battery page (refer to Section 5.5.8).
NOTE
The Battery Rundown Test may take up to 150 minutes to complete and is reported in UTC.
To complete the Backup Battery Test, complete the following steps:
1. Power on each GI 275 with an installed backup battery in Configuration mode.
2. Navigate to the Backup Battery Test page (Calibration/Test → Backup Battery Test).
3. Touch the Before Test Checklist button.
4. Verify that "Discharging" is not displayed under Battery State.
5. Touch the Test Date button and enter the current date.
6. Complete the on-screen checklist. Touch each checklist item once completed. Once all checklist
items have a green check mark, touch the Back button.
7. Touch the Start Test button and follow the on-screen commands.
8. The GI 275 will power off automatically when the test is complete.
9. Power on the GI 275(s) in Configuration mode and verify a PASS was achieved by navigating to
the Backup Battery Test page and touching the Test Results button and then the Rundown Test
Results button.
10. For aircraft that are approved for flight over 25,000 feet, a rundown time of at least 60 minutes is
required to be considered a PASS. For aircraft that are only approved for flight at 25,000 feet or
less, a rundown time of at least 30 minutes is required to be considered a PASS.
190-02246-10
Rev. 11
GI 275 Part 23 AML STC Installation Manual
Page 5-78