Garmin G1000 Maintenance Manual page 196

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GMA Testing
If unit is removed or replaced the following tests are recommended:
Intercom System (ICS) Check
Except for marker beacon operation, an in-aircraft checkout may be performed in the aircraft on
the ramp with known good microphone, headset, and speaker.
Plug in headsets at each ICS position.
1. Ensure that the MAN SQ button is off (no light).
2. Adjust volume for each position and verify that the ICS is working properly.
3. Check Pilot and Copilot ICS positions for isolation and proper operation of volume and
squelch controls.
4. Press the PA key. Verify that microphone audio is heard over the passengers headsets when
the Push-To-Talk (PTT) key is pressed.
Transceiver Operational Check
Perform a ramp test radio check by exercising the installed transceivers, microphone,
microphone key and audio over the headphones and speaker. Verify that communications are
clear and PTT operation is correct for each pilot position.
Select the audio source corresponding to each installed avionics unit (i.e. NAV1, NAV2, COM1,
COM2) and check for audio over the headsets.
• Press the SPKR key and verify that the selected audio is heard over the speaker.
Failsafe Operation Check
GMA 1347D #1:
Turn the GMA 1347D #1 off by pulling the GMA 1347D #1 circuit breaker. This directs all
COM 1 phone audio, MIC audio and MIC key to the pilot's position.
1. Check the failsafe operation by exercising the COM 1 microphone, microphone key and
audio over the headphones. All volume control for the COM audio should be made through
the PFD volume control. Verify proper operation of COM 1 using the failsafe operation.
2. Close the GMA 1347D #1 circuit breaker to continue testing.
GMA 1347D #2:
Turn the GMA 1347D #2 off by pulling the GMA 1347D #2 circuit breaker. This directs all
COM 2 phone audio, MIC audio and MIC key to the co-pilot's position.
1. Check the failsafe operation by exercising the COM 2 microphone, microphone key and
audio over the headphones. All volume control for the COM audio should be made through
the PFD volume control. Verify proper operation of COM 2 using the failsafe operation.
2. Close the GMA 1347D #2 circuit breaker to continue testing.
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G1000 System Maintenance Manual
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