Garmin G900X Installation And Maintenance Manual page 466

C.2.3 GMA 1347 Testing
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.
C.2.3.1 Intercom System (ICS) Check
1. Plug in headsets at each ICS position.
2. Ensure that the MAN SQ key is off (no light).
3. Adjust volume for each position and verify that the ICS is working properly.
4. Check Pilot and Copilot ICS positions for isolation and proper operation of volume and squelch
controls.
C.2.3.2 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.
1. Select the audio source corresponding to each installed avionics unit (i.e. NAV1, NAV2, COM1,
COM2) and check for audio over the headsets.
C.2.3.3 Failsafe Operational Check
1. Turn the GMA 1347 off by pulling the appropriate circuit breaker. This directs all COM 1 phone
audio, MIC audio and MIC key to the pilot's position.
2. 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 through the PFD/MFD
volume control. Verify proper operation of COM 1 using the failsafe operation.
3. Close the appropriate circuit breaker to continue testing.
Page C-22
Revision D
G900X/G950 Installation and Maintenance Manual – PICP & Warranty Registration
190-00719-00