Garmin Diamond DA40, Maintenance Manual

Page: 101 / 156

G1000/DA 40 System Maintenance Manual Page 7-7
190-00303-03 Revision 6
7.2.3 GMA 1347 Test
Except for marker beacon operation, an in-aircraft checkout may be performed in the aircraft with known
good microphone, headset, and speaker.
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.
5. Press the PA key. Verify that microphone audio is heard over the speaker 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.
1. Select the audio source corresponding to each installed avionics unit (i.e. NAV1, NAV2, COM1,
COM2) and check for audio over the headsets.
2. Press the SPKR key and verify that the selected audio is heard over the speaker.
Failsafe Operation Check:
1. Turn the GMA 1347 off by pulling the AUDIO 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 AUDIO circuit breaker to continue testing.
Marker Beacon Test:
Figure 7-3. Marker Beacon Symbology
Using a ramp tester, simulate the outer marker, middle marker and inner marker signals by following the
test equipment manufacturer’s instructions. Verify that each marker audio signal is present over the
headphones and speaker.
Verify that the outer, middle, and inner annunciations appear on the PFD when the corresponding signal
is applied. Marker beacon annunciations appear at the upper left corner of the altitude indicator on the
PFD (Figure 7-3). Operate the MKR MUTE key on the GMA 1347 and ensure that the audio signal is
muted.
If no other service is to be performed, continue to the return-to-service checks in Section 8.